Northwest Natural Holding Co

1. ORGANIZATION AND PRINCIPLES OF CONSOLIDATION

The accompanying consolidated financial statements represent the respective, consolidated financial results of NW Holdings and NW Natural and all respective companies that each registrant directly or indirectly controls, either through majority ownership or otherwise. This is a combined report of NW Holdings and NW Natural, which includes separate consolidated financial statements for each registrant.

NW Natural's regulated natural gas distribution activities are reported in the natural gas distribution (NGD) segment. The NGD segment is NW Natural's core operating business and serves residential, commercial, and industrial customers in Oregon and southwest Washington. The NGD segment is the only reportable segment for NW Holdings and NW Natural. All other activities, water, wastewater and water services businesses, and other investments are aggregated and reported as other at their respective registrant.

NW Holdings and NW Natural consolidate all entities in which they have a controlling financial interest. Investments in corporate joint ventures and partnerships that NW Holdings does not directly or indirectly control, and for which it is not the primary beneficiary, include NNG Financial's investment in Kelso-Beaver Pipeline and NWN Water's investment in Avion Water Company, Inc., which are accounted for under the equity method. NW Natural RNG Holding Company, LLC holds investments in Lexington Renewable Energy, LLC and Dakota City Renewable Energy LLC, which are also accounted for under the equity method. See Note 13 for activity related to equity method investments. NW Holdings and its direct and indirect subsidiaries are collectively referred to herein as NW Holdings, and NW Natural and its direct and indirect subsidiaries are collectively referred to herein as NW Natural. The consolidated financial statements of NW Holdings and NW Natural are presented after elimination of all intercompany balances and transactions.

Notes to the consolidated financial statements reflect the activity of continuing operations for both NW Holdings and NW Natural for all periods presented, unless otherwise noted. Certain reclassifications have been made to conform prior period information to the current presentation. The reclassifications did not have a material effect on our consolidated financial statements.

2. SIGNIFICANT ACCOUNTING POLICIES

Use of Estimates

The preparation of financial statements in conformity with generally accepted accounting principles in the United States of America (U.S. GAAP) requires management to make estimates and assumptions that affect reported amounts in the consolidated financial statements and accompanying notes. Actual amounts could differ from those estimates, and changes would most likely be reported in future periods. Management believes the estimates and assumptions used are reasonable.

Industry Regulation

NW Holdings' principal business is to operate as a holding company for NW Natural and its other subsidiaries. NW Natural's principal business is the distribution of natural gas, which is regulated by the OPUC and WUTC. NW Natural also has natural gas storage services, which are regulated by the FERC, and to a certain extent by the OPUC and WUTC. Additionally, certain of NW Holdings' subsidiaries own water businesses, which are regulated by the public utility commission in the state in which the water utility is located, which is currently Oregon, Washington, Idaho, Texas and Arizona. Wastewater businesses, to the extent they are regulated, are generally regulated by the public utility commissions in the state in which the wastewater utility is located, which is currently Texas and Arizona. Accounting records and practices of the regulated businesses conform to the requirements and uniform system of accounts prescribed by these regulatory authorities in accordance with U.S. GAAP. The businesses in which customer rates are regulated have approved cost-based rates which are intended to allow such businesses to earn a reasonable return on invested capital.

In applying regulatory accounting principles, NW Holdings and NW Natural capitalize or defer certain costs and revenues as regulatory assets and liabilities pursuant to orders of the applicable state public utility commission, which provide for the recovery of revenues or expenses from, or refunds to, utility customers in future periods, including a return or a carrying charge in certain cases.

Amounts NW Natural deferred as regulatory assets and liabilities were as follows:

(1)Unrealized gains or losses on derivatives are non-cash items and, therefore, do not earn a rate of return or a carrying charge. These amounts are recoverable through natural gas distribution rates as part of the annual Purchased Gas Adjustment (PGA) mechanism when realized at settlement.

(2)Refer to the Environmental Cost Deferral and Recovery table in Note 17 for a description of environmental costs.

(3)This deferral represents the margin adjustment resulting from differences between actual and expected volumes.

(4)Balance represents deferred net periodic benefit costs as approved by the OPUC.

(5)Balances consist of deferrals and amortizations under approved regulatory mechanisms and typically earn a rate of return or carrying charge.

(6)Balance represents excess deferred income tax benefits subject to regulatory flow-through. See Note 11.

(7)Estimated costs of removal on certain regulated properties are collected through rates. See "Accounting Policies—Plant, Property, and Accrued Asset Removal Costs" below.

The amortization period for NW Natural's regulatory assets and liabilities ranges from less than one year to an indeterminable period. Regulatory deferrals for gas costs payable are generally amortized over 12 months beginning each November 1 following the gas contract year during which the deferred gas costs are recorded. Similarly, most other regulatory deferred accounts are amortized over 12 months. However, certain regulatory account balances, such as income taxes, environmental costs, pension liabilities, and accrued asset removal costs, are large and tend to be amortized over longer periods once NW Natural has agreed upon an amortization period with the respective regulatory agency.

We believe all costs incurred and deferred at December 31, 2023 are prudent. All regulatory assets are reviewed annually for recoverability, or more often if circumstances warrant. If we should determine that all or a portion of these regulatory assets no longer meet the criteria for continued application of regulatory accounting, then NW Holdings and NW Natural would be required to write-off the net unrecoverable balances in the period such determination is made.

Regulatory interest income of $6.5 million and $7.0 million and regulatory interest expense of $2.9 million and $2.0 million was recognized within other income (expense), net for the years ended December 31, 2023 and 2022, respectively.

Environmental Regulatory Accounting

See Note 17 for information about the SRRM and OPUC orders regarding implementation.

New Accounting Standards

NW Natural and NW Holdings consider the applicability and impact of all accounting standards updates (ASUs) issued by the Financial Accounting Standards Board (FASB). ASUs not listed below were assessed and determined to be either not applicable or are expected to have minimal impact on consolidated financial position or results of operations.

Recently Issued Accounting Pronouncements

JOINT VENTURE FORMATIONS. In August 2023, the FASB issued ASU 2023-05, which requires a joint venture to initially measure all contributions received upon its formation at fair value. The standard is effective for all joint venture entities with a formation date on or after January 1, 2025, with early adoption permitted. The adoption of this standard is not anticipated to have a material impact on our results of operations, liquidity or capital resources.

SEGMENT REPORTING. In November 2023, the FASB issued ASU 2023-07, which requires additional disclosures about significant segment expenses. The disclosures are required beginning with our annual report for the year ending December 31, 2024. The adoption of this standard is not anticipated to have a material impact on our results of operations, liquidity or capital resources.

IMPROVEMENTS TO INCOME TAX DISCLOSURES. In December 2023, the FASB issued ASU 2023-09, which requires additional disclosures about income taxes. The disclosures are required beginning with our annual report for the year ending December 31, 2025. The adoption of this standard is not anticipated to have a material impact on our results of operations, liquidity or capital resources.

Recent Securities and Exchange Commission (SEC) Final Rules

RECOVERY OF ERRONEOUSLY AWARDED COMPENSATION. In October 2022, the SEC adopted the final rule under SEC Release No. 33-11126, Listing Standards for Recovery of Erroneously Awarded Compensation, which directs the national securities exchanges and associations that list securities to establish listing standards requiring each issuer to develop and implement a clawback policy to recoup incentive-based compensation erroneously awarded to executive officers. The policy is included as an exhibit to our annual report for the year ending December 31, 2023.

INSIDER TRADING ARRANGEMENTS. In December 2022, the SEC adopted the final rule under SEC Release No. 33-11138, Insider Trading Arrangements and Related Disclosures, which requires new disclosures regarding insider trading policies and procedures, the use of certain insider trading plans and director and executive compensation regarding equity compensation awards made close in time to disclosure of material nonpublic information. The policy will be included as an exhibit to our annual report for the year ending December 31, 2024.

CYBERSECURITY DISCLOSURES. In July 2023, the SEC issued a final rule under SEC Release No. 33-11216, Cybersecurity Risk Management, Strategy, Governance, and Incident Disclosure, which requires new disclosures regarding material cybersecurity incidents and require periodic disclosures about registrant's processes to assess, identify, and manage material cybersecurity risks, management's role in assessing and managing material cybersecurity risks, and the board of directors' oversight of cybersecurity risks. The disclosures were required beginning with our annual report for the year ending December 31, 2023.

Accounting Policies

The accounting policies discussed below apply to both NW Holdings and NW Natural.

Plant, Property, and Accrued Asset Removal Costs

Plant and property are stated at cost, including capitalized labor, materials, and overhead. In accordance with regulatory accounting standards, the cost of acquiring and constructing long-lived plant and property generally includes an allowance for funds used during construction (AFUDC) or capitalized interest. AFUDC represents the regulatory financing cost incurred when debt and equity funds are used for construction (see “AFUDC” below). When constructed assets are subject to market-based rates rather than cost-based rates, the financing costs incurred during construction are included in capitalized interest in accordance with U.S. GAAP, not as regulatory financing costs under AFUDC.

In accordance with long-standing regulatory treatment, our depreciation rates consist of three components: one based on the average service life of the asset, a second based on the estimated salvage value of the asset, and a third based on the asset’s estimated cost of removal. We collect, through rates, the estimated cost of removal on certain regulated properties through depreciation expense, with a corresponding offset to accumulated depreciation. These removal costs are non-legal obligations as defined by regulatory accounting guidance. Therefore, we have included these costs as non-current regulatory liabilities rather than as accumulated depreciation on our consolidated balance sheets. In the rate setting process, the liability for removal costs is treated as a reduction to the net rate base on which the NGD business has the opportunity to earn its allowed rate of return.

The costs of NGD plant retired or otherwise disposed of are removed from NGD plant and charged to accumulated depreciation for recovery or refund through future rates. Gains from the sale of regulated assets are generally deferred and refunded to customers. For assets not related to NGD, we record a gain or loss upon the disposal of the property, and the gain or loss is recorded in operating income or loss in the consolidated statements of comprehensive income.

The provision for depreciation of NGD property, plant, and equipment is recorded under the group method on a straight-line basis with rates computed in accordance with depreciation studies approved by regulatory authorities. The weighted-average depreciation rate for NGD assets in service was approximately 3.0% for 2023, 2022 and 2021, reflecting the approximate weighted-average economic life of the property. This includes 2023 weighted-average depreciation rates for the following asset categories:2.5% for transmission and distribution plant,2.2% for gas storage facilities,6.7% for general plant, and 5.3% for intangible and other fixed assets.

AFUDC. Certain additions to NGD plant include AFUDC, which represents the net cost of debt and equity funds used during construction. AFUDC is calculated using actual interest rates for debt and authorized rates for ROE, if applicable. If short-term debt balances are less than the total balance of construction work in progress, then a composite AFUDC rate is used to represent interest on all debt funds, shown as a reduction to interest charges, and on ROE funds, shown as other income. While cash is not immediately recognized from recording AFUDC, it is realized in future years through rate recovery resulting from the higher NGD cost of service. Our composite AFUDC rate was 7.5% in 2023,2.8% in 2022, and 0.7% in 2021.

IMPAIRMENT OF LONG-LIVED ASSETS. We review the carrying value of long-lived assets whenever events or changes in circumstances indicate the carrying amount of the assets may not be recoverable. Factors that would necessitate an impairment assessment of long-lived assets include a significant adverse change in the extent or manner in which the asset is used, a significant adverse change in legal factors or business climate that could affect the value of the asset, or a significant decline in the observable market value or expected future cash flows of the asset, among others.

When such factors are present, we assess the recoverability by determining whether the carrying value of the asset will be recovered through expected future cash flows. An asset is determined to be impaired when the carrying value of the asset exceeds the expected undiscounted future cash flows from the use and eventual disposition of the asset. If an impairment is indicated, we record an impairment loss for the difference between the carrying value and the fair value of the long-lived assets. Fair value is estimated using appropriate valuation methodologies, which may include an estimate of discounted cash flows.

Cash and Cash Equivalents

Cash and cash equivalents include cash on hand plus highly liquid investment accounts with original maturity dates of three months or less. These investments are readily convertible to cash with fair value approximating cost.

At December 31, 2023, NW Holdings had outstanding checks of $7.5 million, substantially all of which is recorded at NW Natural, and at December 31, 2022, NW Holdings had $5.8 million outstanding checks. These balances are included in accounts payable in the NW Holdings and NW Natural balance sheets.

Restricted Cash

Restricted cash is primarily comprised of funds from public purpose charges for programs that assist low-income customers with bill payments or energy efficiency. These balances are included in other current assets in the NW Holdings and NW Natural balance sheets. There were no transfers between restricted cash and cash and cash equivalents during the years ended December 31, 2023 and 2022.

The following table provides a reconciliation of the cash, cash equivalents and restricted cash balances at NW Holdings as of December 31, 2023 and 2022:

The following table provides a reconciliation of the cash, cash equivalents and restricted cash balances at NW Natural as of December 31, 2023 and 2022:

Revenue Recognition and Accrued Unbilled Revenue

Revenues, derived primarily from the sale and transportation of natural gas, are recognized upon delivery of gas or water, or service to customers. Revenues include accruals for gas or water delivered but not yet billed to customers based on estimates of deliveries from meter reading dates to month end (accrued unbilled revenue). Accrued unbilled revenue is dependent upon a number of factors that require management’s judgment, including total natural gas receipts and deliveries, customer use of natural gas or water by billing cycle, and weather factors. Accrued unbilled revenue is reversed the following month when actual billings occur. NW Holdings' accrued unbilled revenue at December 31, 2023 and 2022 was $83.1 million and $89.0 million, respectively, substantially all of which is accrued unbilled revenue at NW Natural.

Revenues not related to NGD are derived primarily from Interstate Storage Services, asset management activities at the Mist gas storage facility, and other investments and business activities. At the Mist underground storage facility, revenues are primarily firm service revenues in the form of fixed monthly reservation charges. In addition, we also have asset management service revenue from an independent energy marketing company that optimizes commodity, storage, and pipeline capacity release transactions. Under this agreement, guaranteed asset management revenue is recognized using a straight-line, pro-rata methodology over the term of each contract. Revenues earned above the guaranteed amount are recognized as they are earned.

Revenue Taxes

Revenue-based taxes are primarily franchise taxes, which are collected from customers and remitted to taxing authorities. Revenue taxes are included in operating expenses in the statements of comprehensive income for NW Holdings and NW Natural. Revenue taxes at NW Holdings were $48.7 million, $41.8 million, and $34.7 million for 2023, 2022, and 2021, respectively.

Accounts Receivable and Allowance for Uncollectible Accounts

Accounts receivable consist primarily of amounts due for natural gas sales and transportation services to NGD customers, plus amounts due for gas storage services. NW Holdings and NW Natural establish allowances for uncollectible accounts (allowance) for trade receivables, including accrued unbilled revenue, based on the aging of receivables, collection experience of past due account balances including payment plans, and historical trends of write-offs as a percent of revenues. A specific allowance is established and recorded for large individual customer receivables when amounts are identified as unlikely to be partially or fully recovered. Inactive accounts are written-off against the allowance after they are 120 days past due or when deemed uncollectible. Differences between the estimated allowance and actual write-offs will occur based on a number of factors, including changes in economic conditions, customer creditworthiness, and natural gas prices. The allowance for uncollectible accounts is adjusted quarterly, as necessary, based on information currently available.

ALLOWANCE FOR TRADE RECEIVABLES. The payment term of our NGD receivables is generally 15 days. For these short-term receivables, it is not expected that forecasted economic conditions would significantly affect the loss estimates under stable economic conditions. For extreme situations like a financial crisis, natural disaster, and the economic slowdown caused by the COVID-19 pandemic, we enhanced our review and analysis.

For the residential and commercial uncollectible provision, we primarily followed our standard methodology, which includes assessing historical write-off trends and current information on delinquent accounts. Beginning October 1, 2022, new collection rules from the OPUC applied to residential and commercial customers. This included enhanced protections for low-income customers, a return to pre-pandemic time payment arrangements terms, revised disconnection rules during the heating season, and other items. As a result of these Oregon rule changes and our recent collection process experience, we augmented our provision review for accounts in the following categories: closed or inactive accounts aged less than 120 days, accounts on payment plans, and all other open accounts not on payment plans. For industrial accounts, we continue to assess the provision on an account-by-account basis with specific reserves taken as necessary. NW Natural will continue to closely monitor and evaluate our accounts receivable and the provision for uncollectible accounts.

The following table presents the activity related to the NW Holdings provision for uncollectible accounts by pool, substantially all of which is related to NW Natural's accounts receivable:

ALLOWANCE FOR NET INVESTMENTS IN SALES-TYPE LEASES. NW Natural currently holdstwo net investments in sales-type leases, with substantially all of the net investment balance related to the North Mist natural gas storage agreement with Portland General Electric (PGE) which is billed under an OPUC-approved rate schedule. See Note 7 for more information on the North Mist lease. Due to the nature of this service, PGE may recover the costs of the lease through general rate cases. Therefore, we expect the risk of loss due to the credit of this lessee to be remote. As such, no allowance for uncollectibility was recorded for our sales-type lease receivables. NW Natural will continue monitoring the credit health of the lessees and the overall economic environment, including the economic factors closely tied to the financial health of our current and future lessees.

Inventories

NGD gas inventories, which consist of natural gas in storage for NGD customers, are stated at the lower of weighted-average cost or net realizable value. The regulatory treatment of these inventories provides for cost recovery in customer rates. NGD gas inventories injected into storage are priced in inventory based on actual purchase costs, and those withdrawn from storage are charged to cost of gas during the period they are withdrawn at the weighted-average inventory cost.

Gas storage inventories mainly consist of natural gas received as fuel-in-kind from storage customers. Gas storage inventories are valued at the lower of average cost or net realizable value. Cushion gas is not included in inventory balances, is recorded at original cost, and is classified as a long-term plant asset.

Materials and supplies inventories consist of inventories both related to and unrelated to NGD and are stated at the lower of average cost or net realizable value.

NW Natural's NGD and gas storage inventories totaled $47.2 million and $61.9 million at December 31, 2023 and 2022, respectively. At December 31, 2023 and 2022, NW Holdings' materials and supplies inventories, which are comprised primarily of NW Natural's materials and supplies, totaled $25.6 million and $23.5 million, respectively.

During 2023 and 2022, NW Natural entered into certain agreements to purchase renewable thermal certificates (RTCs). RTCs are initially recorded at cost and subsequently assessed for impairment based on the lower-of-cost or market model. NW Natural's RTCs inventory totaled $0.5 million and $1.7 million at December 31, 2023 and 2022, respectively.

Greenhouse Gas Allowances

NW Natural is subject to greenhouse gas (GHG) emission reduction requirements under the Washington Climate Commitment Act (CCA) regulations and is likely to be subject to GHG emission reductions under a separate program in Oregon upon conclusion of the new ODEQ rulemaking. The new rulemaking was commenced upon the judicial invalidation of the prior rules promulgated by the ODEQ and is expected to take approximately 12 months.

Under Washington's CCA, emission reduction compliance mechanisms include: 1) allowances distributed at no cost by the state, 2) purchasing allowances at state-run auctions or secondary markets, 3) purchasing carbon offsets, and 4) supplying alternative gaseous fuels, such as renewable natural gas and hydrogen.

NW Natural will account for all purchased Washington allowances as inventory at the lower of cost or market. Any compliance instruments or allowances that are acquired through government allocations at no cost will be accounted for as inventory at no cost. As of December 31, 2023, NW Natural had $39.3 million of emissions allowances for compliance in Washington recorded as inventory.

The CCA allows for the sale of compliance instruments or allowances, and as a result, should NW Natural sell these it will recognize revenue when title to the instrument or allowance is transferred to a counterparty, and NW Natural will recognize expense at the time of recognition of the related sale. In September and December 2023, NW Natural consigned no-cost allowances to Washington auctions and received $10.0 million and $7.1 million, respectively, in cash, which proceeds were recorded as a regulatory liability for the benefit of customers.

We measure the compliance obligation, which is based on emissions, at the carrying value of inventory held plus the fair value of any additional emission allowances NW Natural would need to purchase to satisfy the obligations. Under the Washington program, NW Natural has recognized a $19.9 million liability as of December 31, 2023. We expect that the costs to comply with the Washington program will be recovered from utility customers through rates. As a result, NW Natural recognized $20.5 million of deferred costs as of December 31, 2023.

Gas Reserves

Gas reserves are payments to acquire and produce natural gas reserves. Gas reserves are stated at cost, adjusted for regulatory amortization, with the associated deferred tax benefits recorded as liabilities on the balance sheet. The current portion is calculated based on expected gas deliveries within the next fiscal year. NW Natural recognizes regulatory amortization of this asset on a volumetric basis calculated using the estimated gas reserves and the estimated therms extracted and sold each month. The amortization of gas reserves is recorded to cost of gas along with gas production revenues and production costs. See Note 13.

Derivatives

NW Natural's derivatives are measured at fair value and recognized as either assets or liabilities on the balance sheet. Changes in the fair value of the derivatives are recognized in earnings unless specific regulatory or hedge accounting criteria are met. Accounting for derivatives and hedges provides an exception for contracts intended for normal purchases and normal sales for which physical delivery is probable. In addition, certain derivative contracts are approved by regulatory authorities for recovery or refund through customer rates. Accordingly, the changes in fair value of these approved contracts are deferred as regulatory assets or liabilities pursuant to regulatory accounting principles. NW Natural's financial derivatives generally qualify for deferral under regulatory accounting. NW Natural's index-priced physical derivative contracts also qualify for regulatory deferral accounting treatment.

Derivative contracts entered into for NGD requirements after the annual PGA rate has been set and maturing during the PGA year are subject to the PGA incentive sharing mechanism. In Oregon, NW Natural participates in a PGA sharing mechanism under which it is required to select either an 80% or 90% deferral of higher or lower gas costs such that the impact on current earnings from the gas cost sharing is either 20% or 10% of gas cost differences compared to PGA prices, respectively. For each of the PGA years in Oregon beginning November 1, 2023, 2022, and 2021, NW Natural selected the 90% deferral of gas cost differences. In Washington,100% of the differences between the PGA prices and actual gas costs are deferred. See Note 15.

NW Holdings and NW Natural have financial derivative policies that set forth guidelines for using selected derivative products to support prudent risk management strategies within designated parameters. NW Natural's objective for using derivatives is to decrease the volatility of gas prices, interest rates, and cash flows without speculative risk. The use of derivatives is permitted only after the risk exposures have been identified, are determined to exceed acceptable tolerance levels, and are determined necessary to support normal business activities. NW Natural does not enter into derivative instruments for trading purposes. All commodity and foreign exchange derivatives are currently held at NW Natural, and interest rate swaps are held at NW Holdings and NWN Water.

In accordance with fair value accounting, we use the following fair value hierarchy for determining inputs for our debt, pension plan assets, and derivative fair value measurements:

•Level 1: Valuation is based on quoted prices for identical instruments traded in active markets;

•Level 2: Valuation is based on quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-based valuation techniques for which all significant assumptions are observable in the market; and

•Level 3: Valuation is generated from model-based techniques that use significant assumptions not observable in the market. These unobservable assumptions reflect our own estimates of assumptions market participants would use in valuing the asset or liability.

In addition, the fair value for certain pension trust investments is determined using Net Asset Value per share (NAV) as a practical expedient, and therefore they are not classified within the fair value hierarchy. These investments primarily consist of institutional investment products.

When developing fair value measurements, it is our policy to use quoted market prices whenever available or to maximize the use of observable inputs and minimize the use of unobservable inputs when quoted market prices are not available. Fair values are primarily developed using industry-standard models that consider various inputs including: (a) quoted future prices for commodities; (b) forward currency prices; (c) time value; (d) volatility factors; (e) current market and contractual prices for underlying instruments; (f) market interest rates and yield curves; (g) credit spreads; and (h) other relevant economic measures. NW Natural considers liquid points for natural gas hedging to be those points for which there are regularly published prices in a nationally recognized publication or where the instruments are traded on an exchange.

Goodwill and Business Combinations

NW Holdings, through its wholly-owned subsidiary NWN Water and NWN Water's wholly-owned subsidiaries, has completed various acquisitions that resulted in the recognition of goodwill. Goodwill is measured as the excess of the acquisition-date fair value of the consideration transferred over the acquisition-date fair value of the net identifiable assets assumed. Adjustments are recorded during the measurement period to finalize the allocation of the purchase price. The carrying value of goodwill is reviewed annually during the fourth quarter, or whenever events or changes in circumstance indicate that such carrying values may not be recoverable. The goodwill assessment policy begins with a qualitative analysis in which events and circumstances are evaluated, including macroeconomic conditions, industry and market conditions, regulatory environments, and overall financial performance of the reporting unit. If the qualitative assessment indicates that the carrying value may be at risk of recoverability, a quantitative evaluation is performed to measure the carrying value of the goodwill against the fair value of the reporting unit. The reporting unit is determined primarily based on current operating segments and the level of review provided by the Chief Operating Decision Maker (CODM) and/or segment management on the operating segment's financial results. Reporting units are evaluated periodically for changes in the corporate environment.

As of December 31, 2023 and 2022, NW Holdings had goodwill of $163.3 million and $149.3 million, respectively. All of NW Holdings' goodwill was acquired through the business combinations completed by NWN Water and its wholly-owned subsidiaries. No impairment charges were recorded as a result of the fourth quarter goodwill impairment assessment.

Business combinations are accounted for using the acquisition method. The cost of an acquisition is measured as the aggregate of the consideration transferred, measured at fair value at the acquisition date, and the fair value of any non-controlling interest in the acquiree. Acquisition-related costs are expensed as incurred. When NW Natural acquires a business, it assesses the financial assets acquired and liabilities assumed for appropriate classification and designation in accordance with the contractual terms, economic circumstances and pertinent conditions as of the acquisition date. When there is substantial judgment or uncertainty around the fair value of acquired assets, we may engage a third party expert to assist in determining the fair values of certain assets or liabilities.

Income Taxes

We account for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the enactment date period unless, for NW Natural, a regulatory order specifies deferral of the effect of the change in tax rates over a longer period of time.

For NW Natural, deferred income tax assets and liabilities are also recognized for temporary differences where the deferred income tax benefits or expenses have previously been flowed through in the ratemaking process of the NGD business. Regulatory tax assets and liabilities are recorded on these deferred tax assets and liabilities to the extent it is believed they will be recoverable from or refunded to customers in future rates.

Investment tax credits associated with rate regulated plant additions are deferred for financial statement purposes and amortized over the estimated useful lives of the related plant.

NW Holdings files consolidated or combined income tax returns that include NW Natural. Income tax expense is allocated on a separate company basis incorporating certain consolidated return considerations. Subsidiary income taxes payable or receivable are generally settled with NW Holdings, the common agent for income tax matters.

Interest and penalties related to unrecognized tax benefits, if any, are recognized within income tax expense and accrued interest and penalties are recognized within the related tax liability line in the consolidated balance sheets. No accrued interest or penalties for uncertain tax benefits have been recorded. See Note 11.

Environmental Contingencies

Loss contingencies are recorded as liabilities when it is probable a liability has been incurred and the amount of the loss is reasonably estimable in accordance with accounting standards for contingencies. Estimating probable losses requires an analysis of uncertainties that often depend upon judgments about potential actions by third parties. Accruals for loss contingencies are recorded based on an analysis of potential results.

With respect to environmental liabilities and related costs, estimates are developed based on a review of information available from numerous sources, including completed studies and site specific negotiations. NW Natural's policy is to accrue the full amount of such liability when information is sufficient to reasonably estimate the amount of probable liability. When information is not available to reasonably estimate the probable liability, or when only the range of probable liabilities can be estimated and no amount within the range is more likely than another, it is our policy to accrue at the low end of the range. Accordingly, due to numerous uncertainties surrounding the course of environmental remediation and the preliminary nature of several site investigations, in some cases, it may not be possible to reasonably estimate the high end of the range of possible loss. In those cases, the nature of the potential loss and the fact that the high end of the range cannot be reasonably estimated is disclosed. See Note 17.

Unconsolidated Affiliates

NW Holdings, NW Natural and NWN Water have equity interests in businesses which we account for under the equity method as we do not exercise control of the major operating and financial policies. The business transactions with our equity method investments are not significant. We regularly assess the profitability and valuation of our investments for any potential impairment. See Note 13.

Cloud Computing Arrangements

Implementation costs associated with its cloud computing arrangements are capitalized consistent with costs capitalized for internal-use software. Capitalized implementation costs are included in other assets in the consolidated balance sheets. The implementation costs are amortized over the term of the related hosting agreement, including renewal periods that are reasonably certain to be exercised. Amortization expense of implementation costs are recorded as operations and maintenance expenses in the consolidated statements of comprehensive income. The implementation costs are included within operating activities in the consolidated statements of cash flows.

Subsequent Events

We monitor significant events occurring after the balance sheet date and prior to the issuance of the financial statements to determine the impacts, if any, of events on the financial statements to be issued.

3. EARNINGS PER SHARE

Basic earnings or loss per share are computed using NW Holdings' net income or loss and the weighted average number of common shares outstanding for each period presented. Diluted earnings per share are computed in the same manner, except using the weighted average number of common shares outstanding plus the effects of the assumed exercise of stock options and the payment of estimated stock awards from other stock-based compensation plans that are outstanding at the end of each period presented. Anti-dilutive stock awards are excluded from the calculation of diluted earnings or loss per common share.

NW Holdings' diluted earnings or loss per share are calculated as follows:

4. SEGMENT INFORMATION

We primarily operate inone reportable business segment, which is NW Natural's local gas distribution business and is referred to as the NGD segment. NW Natural and NW Holdings also have investments and business activities not specifically related to the NGD segment, which are aggregated and reported as other and described below for each entity.

No individual customer accounts for over 10% of NW Holdings' or NW Natural's operating revenues.

Natural Gas Distribution

NW Natural's local gas distribution segment (NGD) is a regulated utility principally engaged in the purchase, sale, and delivery of natural gas and related services to customers in Oregon and southwest Washington. The NGD business is responsible for building and maintaining a safe and reliable pipeline distribution system, purchasing sufficient gas supplies from producers and marketers, contracting for firm and interruptible transportation of gas over interstate pipelines to bring gas from the supply basins into its service territory, and re-selling the gas to customers subject to rates, terms, and conditions approved by the OPUC or WUTC. NGD also includes taking customer-owned gas and transporting it from interstate pipeline connections, or city gates, to the customers’ end-use facilities for a fee, which is approved by the OPUC or WUTC. Approximately 88% of NGD customers are located in Oregon and 12% in Washington. On an annual basis, residential and commercial customers typically account for around 60% of total NGD volumes delivered and around 90% of NGD margin. Industrial customers largely account for the remaining volumes and NGD margin. A small amount of the margin is also derived from miscellaneous services, gains or losses from an incentive gas cost sharing mechanism, and other service fees.

Industrial sectors served by the NGD business include: pulp, paper, and other forest products; the manufacture of electronic, electrochemical and electrometallurgical products; the processing of farm and food products; the production of various mineral products; metal fabrication and casting; the production of machine tools, machinery, and textiles; the manufacture of asphalt, concrete, and rubber; printing and publishing; nurseries; and government and educational institutions.

In addition to NW Natural's local gas distribution business, the NGD segment also includes the portion of the Mist underground storage facility used to serve NGD customers, North Mist gas storage, NWN Gas Reserves, which is a wholly-owned subsidiary of Energy Corp, and NW Natural RNG Holding Company, LLC, a holding company established to invest in the development and procurement of regulated renewable natural gas for NW Natural.

NW Natural's activities in Other include Interstate Storage Services and third-party asset management services for the Mist facility in Oregon, appliance retail center operations, and corporate operating and non-operating revenues and expenses that cannot be allocated to NGD operations.

Earnings from Interstate Storage Services assets are primarily related to firm storage capacity revenues. Earnings from the Mist facility also include revenue, net of amounts shared with NGD customers, from management of NGD assets at Mist and upstream pipeline capacity when not needed to serve NGD customers. Under the Oregon sharing mechanism, NW Natural retains 80% of the pre-tax income from these services when the costs of the capacity were not included in NGD rates, or 10% of the pre-tax income when the costs have been included in these rates. The remaining 20% and 90%, respectively, are recorded to a deferred regulatory account for crediting back to NGD customers.

NW Holdings' activities in Other include all remaining activities not associated with NW Natural, specifically NWN Water, which consolidates the water and wastewater utility operations and water services businesses; NWN Water's equity investment in Avion Water Company, Inc.; NWN Gas Storage, a wholly-owned subsidiary of NWN Energy; other pipeline assets in NNG Financial; and NW Natural Renewables Holdings, LLC and its non-regulated renewable natural gas activities. Other also includes corporate revenues and expenses that cannot be allocated to other operations, including certain business development activities.

Segment Information Summary

Inter-segment transactions were immaterial for the periods presented. The following table presents summary financial information concerning the reportable segment and other operations.

Natural Gas Distribution Margin

NGD margin is the primary financial measure used by the CODM, consisting of NGD operating revenues, reduced by the associated cost of gas, environmental remediation expense, and revenue taxes. The cost of gas purchased for NGD customers is generally a pass-through cost in the amount of revenues billed to regulated NGD customers. Environmental remediation expense represents collections received from customers through environmental recovery mechanisms in Oregon and Washington as well as adjustments for the Oregon environmental earnings test when applicable. This is offset by environmental remediation expense presented in operating expenses. Revenue taxes are collected from NGD customers and remitted to taxing authorities. The collections from customers are offset by the expense recognition of the obligation to the taxing authority. By subtracting cost of gas, environmental remediation expense, and revenue taxes from NGD operating revenues, NGD margin provides a key metric used by the CODM in assessing the performance of the NGD segment.

The following table presents additional segment information concerning NGD margin:

5. COMMON STOCK

As of December 31, 2023 and 2022, NW Holdings had 100 million shares of common stock authorized. As of December 31, 2023, NW Holdings had 306,757 shares reserved for issuance of common stock under the Employee Stock Purchase Plan (ESPP) and 325,201 shares reserved for issuance under the Dividend Reinvestment and Direct Stock Purchase Plan (DRPP). At NW Holdings' election, shares sold through the DRPP may be purchased in the open market or through original issuance of shares reserved for issuance under the DRPP.

In August 2021, NW Holdings initiated an at-the-market (ATM) equity program by entering into an equity distribution agreement under which NW Holdings may issue and sell from time to time shares of common stock, no par value, having an aggregate gross sales price of up to $200 million. NW Holdings is under no obligation to offer and sell common stock under the ATM equity program, which expires in August 2024. Any shares of common stock offered under the ATM equity program are registered on

NW Holdings’ universal shelf registration statement filed with the SEC. During the year ended December 31, 2023, NW Holdings issued and sold 1,646,325 shares of common stock pursuant to the ATM equity program resulting in cash proceeds of $66.4 million, net of fees and commissions paid to agents of $1.2 million. As of December 31, 2023, NW Holdings had $43.5 million of equity available for issuance under the program. The ATM equity program was initiated to raise funds for general corporate purposes, including equity contributions to NW Holdings’ subsidiaries, NW Natural and NW Natural Water. Contributions to NW Natural and NW Natural Water will be used for general corporate purposes.

Stock Repurchase Program

NW Holdings has a share repurchase program under which it may purchase its common shares on the open market or through privately negotiated transactions. NW Holdings currently has Board authorization to repurchase up to an aggregate of the greater of 2.8 million shares or $100 million. No shares of common stock were repurchased pursuant to this program during the year ended December 31, 2023. Since the plan’s inception in 2000 under NW Natural, a total of 2.1 million shares have been repurchased at a total cost of $83.3 million.

The following table summarizes the changes in the number of shares of NW Holdings' common stock issued and outstanding:

6. REVENUE

The following table presents disaggregated revenue from continuing operations:

NW Natural's revenue represents substantially all of NW Holdings' revenue and is recognized for both registrants when the obligation to customers is satisfied and in the amount expected to be received in exchange for transferring goods or providing services. Revenue from contracts with customers containsone performance obligation that is generally satisfied over time, using the output method based on time elapsed, due to the continuous nature of the service provided. The transaction price is determined by a set price agreed upon in the contract or dependent on regulatory tariffs. Customer accounts are settled on a monthly basis or paid at time of sale and based on historical experience. It is probable that we will collect substantially all of the consideration to which we are entitled. We evaluated the probability of collection in accordance with the current expected credit losses standard.

NW Holdings and NW Natural do not have any material contract assets, as net accounts receivable and accrued unbilled revenue balances are unconditional and only involve the passage of time until such balances are billed and collected. NW Holdings and NW Natural do not have any material contract liabilities.

Revenue taxes are included in operating revenues with an equal and offsetting expense recognized in operating expenses in the consolidated statements of comprehensive income. Revenue-based taxes are primarily franchise taxes, which are collected from NGD customers and remitted to taxing authorities.

Natural Gas Distribution

Natural Gas Sales

NW Natural's primary source of revenue is providing natural gas to customers in the NGD service territory, which includes residential, commercial, industrial and transportation customers. NGD revenue is generally recognized over time upon delivery of the gas commodity or service to the customer, and the amount of consideration received and recognized as revenue is dependent on the Oregon and Washington tariffs. Customer accounts are to be paid in full each month, and there isno right of return or warranty for services provided. Revenues include firm and interruptible sales and transportation services, franchise taxes recovered from the customer, late payment fees, service fees, and accruals for gas delivered but not yet billed (accrued unbilled revenue). The accrued unbilled revenue balance is based on estimates of deliveries during the period from the last meter reading and management judgment is required for a number of factors used in this calculation, including customer use and weather factors.

We applied the significant financing practical expedient and have not adjusted the consideration NW Natural expects to receive from NGD customers for the effects of a significant financing component as all payment arrangements are settled annually. Due to the election of the right to invoice practical expedient, we do not disclose the value of unsatisfied performance obligations.

Alternative Revenue

Weather normalization (WARM) and decoupling mechanisms are considered to be alternative revenue programs. Alternative revenue programs are considered to be contracts between NW Natural and its regulator and are excluded from revenue from contracts with customers.

Leasing Revenue

Leasing revenue primarily consists of revenues from NW Natural's North Mist Storage contract with Portland General Electric (PGE) in support of PGE's gas-fired electric power generation facilities under an initial 30-year contract with options to extend, totaling up to an additional 50 years upon mutual agreement of the parties. The facility is accounted for as a sales-type lease with regulatory accounting deferral treatment. The investment is included in rate base under an established cost-of-service tariff schedule, with revenues recognized according to the tariff schedule and as such, profit upon commencement was deferred and will be amortized over the lease term. Leasing revenue also contains rental revenue from small leases of property owned by NW Natural to third parties. The majority of these transactions are accounted for as operating leases and the revenue is recognized over the term of the lease agreement. Lease revenue is excluded from revenue from contracts with customers. See Note 7 for additional information.

NW Natural Other

Gas Storage Revenue

NW Natural's other revenue includes gas storage activity, which includes Interstate Storage Services used to store natural gas for customers. Gas storage revenue is generally recognized over time as the gas storage service is provided to the customer and the amount of consideration received and recognized as revenue is dependent on set rates defined per the storage agreements. Noncash consideration in the form of dekatherms of natural gas is received as consideration for providing gas injection services to gas storage customers. This noncash consideration is measured at fair value using the average spot rate. Customer accounts are generally paid in full each month, and there isno right of return or warranty for services provided. Revenues include firm and interruptible storage services, net of the profit sharing amount refunded to NGD customers.

Asset Management Revenue

Revenues include the optimization of storage assets and pipeline capacity and are provided net of the profit sharing amount refunded to NGD customers. Certain asset management revenues received are recognized over time using a straight-line approach over the term of each contract, and the amount of consideration received and recognized as revenue is dependent on a variable pricing model. Variable revenues earned above guaranteed amounts are estimated and recognized at the end of each period using the most likely amount approach. Additionally, other asset management revenues may be based on a fixed rate. Generally, asset management accounts are settled on a monthly basis.

As of December 31, 2023, unrecognized revenue for the fixed component of the transaction price related to gas storage and asset management revenue was approximately $78.1 million. Of this amount, approximately $19.9 million will be recognized in 2024, $19.0 million in 2025, $14.9 million in 2026, $7.4 million in 2027, and $16.9 million thereafter. The amounts presented here are calculated using current contracted rates.

Appliance Retail Center Revenue

NW Natural owns and operates an appliance store that is open to the public, where customers can purchase natural gas home appliances. Revenue from the sale of appliances is recognized at the point in time in which the appliance is transferred to the third party responsible for delivery and installation services and when the customer has legal title to the appliance. It is required that the sale be paid for in full prior to transfer of legal title. The amount of consideration received and recognized as revenue varies with changes in marketing incentives and discounts offered to customers.

NW Holdings Other

NW Holdings' primary source of other revenue is providing water and wastewater services to customers. Water and wastewater service revenue is generally recognized over time upon delivery of the water commodity or service to the customer, and the amount of consideration received and recognized as revenue is dependent on the tariffs established in the state we operate. Customer accounts are to be paid in full each month, and there isno right of return or warranty for services provided.

We applied the significant financing practical expedient and have not adjusted the consideration we expect to receive from water distribution and wastewater collection customers for the effects of a significant financing component as all payment arrangements are settled annually. Due to the election of the right to invoice practical expedient, we do not disclose the value of unsatisfied performance obligations.

7. LEASES

Lease Revenue

Leasing revenue primarily consists of NW Natural's North Mist natural gas storage agreement with PGE which is billed under an OPUC-approved rate schedule and includes an initial 30-year term beginning May 2019 with options to extend, totaling up to an additional 50 years upon mutual agreement of the parties. Under U.S. GAAP, this agreement is classified as a sales-type lease and qualifies for regulatory accounting deferral treatment. The investment in the storage facility is included in rate base under a separately established cost-of-service tariff, with revenues recognized according to the tariff schedule. As such, the selling profit that was calculated upon commencement as part of the sale-type lease recognition was deferred and will be amortized over the lease term. Billing rates under the cost-of-service tariff will be updated annually to reflect current information including depreciable asset levels, forecasted operating expenses, and the results of regulatory proceedings, as applicable, and revenue received under this agreement is recognized as operating revenue on the consolidated statements of comprehensive income. There areno variable payments or residual value guarantees. The lease does not contain an option to purchase the underlying assets.

NW Natural also maintains a sales-type lease for specialized compressor facilities to provide high pressure compressed natural gas (CNG) services. Lease payments are outlined in an OPUC-approved rate schedule over a 10-year term. There are no variable payments or residual value guarantees. The selling profit computed upon lease commencement was not significant.

Our lessor portfolio also contains small leases of property owned by NW Natural to third parties. These transactions are accounted for as operating leases and the revenue is recognized over the term of the lease agreement.

The components of lease revenue at NW Natural were as follows:

Additionally, lease revenue of $0.6 million, $0.6 million and $0.5 million was recognized for each of the years ended December 31, 2023, 2022, and 2021, respectively, related to operating leases associated with non-utility property rentals. Lease revenue related to these leases was presented in other income (expense), net on the consolidated statements of comprehensive income as it is non-operating income.

Total future minimum lease payments to be received under non-cancelable leases at December 31, 2023 are as follows:

The total leases receivable above is reported under the NGD segment and the short- and long-term portions are included within other current assets and assets under sales-type leases on the consolidated balance sheets, respectively. The total amount of unguaranteed residual assets was $5.5 million and $5.1 million at December 31, 2023 and 2022, respectively, and is included in assets under sales-type leases on the consolidated balance sheets. Additionally, under regulatory accounting, the revenues and expenses associated with these agreements are presented on the consolidated statements of comprehensive income such that their presentation aligns with similar regulated activities at NW Natural.

Lease Expense

Operating Leases

We have operating leases for land, buildings and equipment. Our primary lease is for NW Natural's headquarters and operations center. Our leases have remaining lease terms ofnine months to 16 years. Many of our lease agreements include options to extend the lease, which we do not include in our minimum lease terms unless they are reasonably certain to be exercised. Short-term leases with a term of 12 months or less are not recorded on the balance sheet.

As most of our leases do not provide an implicit rate and are entered into by NW Natural, we use an estimated discount rate representing the rate we would have incurred to finance the funds necessary to purchase the leased asset and is based on information available at the lease commencement date in determining the present value of lease payments.

The components of lease expense, a portion of which is capitalized, were as follows:

Supplemental balance sheet information related to operating leases as of December 31, 2023 is as follows:

Supplemental balance sheet information related to operating leases as of December 31, 2022 is as follows:

The weighted-average remaining lease terms and weighted-average discount rates for the operating leases at NW Natural were as follows:

Headquarters and Operations Center Lease

NW Natural commenced a 20-year operating lease agreement in March 2020 for a new headquarters and operations center in Portland, Oregon. There is an option to extend the term of the lease for two additional periods ofseven years. There is a material timing difference between the minimum lease payments and expense recognition as calculated under operating lease accounting rules. OPUC issued an order allowing us to align our expense recognition with cash payments for ratemaking purposes. We recorded the difference between the minimum lease payments and the aggregate of the imputed interest on the finance lease obligation and amortization of the right-of-use asset as a regulatory asset on our balance sheet. The balance of the regulatory asset was $8.0 million and $6.9 million as of December 31, 2023 and 2022, respectively.

Maturities of operating lease liabilities at December 31, 2023 were as follows:

As of December 31, 2023, there wereno finance lease liabilities at NW Natural.

Cash Flow Information

Supplemental cash flow information related to leases was as follows:

Finance Leases

NW Natural also leases building storage spaces for use as a gas meter room in order to provide natural gas to multifamily or mixed use developments. These contracts are accounted for as finance leases and typically involve a one-time upfront payment withno remaining liability. The right of use asset for finance leases was $2.6 million and $2.3 million at December 31, 2023 and 2022, respectively.

8. STOCK-BASED COMPENSATION

Stock-based compensation plans are designed to promote stock ownership in NW Holdings by employees and officers of NW Holdings and its affiliates. These compensation plans include a Long Term Incentive Plan (LTIP) and an ESPP.

Long Term Incentive Plan

The LTIP is intended to provide a flexible, competitive compensation program for eligible officers and key employees. Under the LTIP, shares of NW Holdings common stock are authorized for equity incentive grants in the form of stock, restricted stock, restricted stock units, stock options, or performance shares. An aggregate of 1,100,000 shares were authorized for issuance as of December 31, 2023. Shares awarded under the LTIP may be purchased on the open market or issued as original shares.

Of the 1,100,000 shares of common stock authorized for LTIP awards at December 31, 2023, there were 180,755 shares available for issuance under any type of award. This assumes market, performance, and service-based grants currently outstanding are awarded at the target level. There wereno outstanding grants of restricted stock or stock options under the LTIP at December 31, 2023 or 2022. The LTIP stock awards are compensatory awards for which compensation expense is based on the fair value of stock awards, with expense being recognized over the performance and vesting period of the outstanding awards. Forfeitures are recognized as they occur.

Performance Shares

LTIP performance shares incorporate a combination of market, performance, and service-based factors. The following table summarizes performance share expense information:

(1)In addition to common stock shares, a participant also receives a dividend equivalent cash payment equal to the number of shares of common stock received on the award payout multiplied by the aggregate cash dividends paid per share during the performance period.

(2)Amount represents the expense recognized in the third year of the vesting period noted above. For the 2019-2021, 2020-2022, and 2021-2023 grants, mutual understanding of the award's key terms was established in the third year of the vesting period, triggering full expense recognition in 2021, 2022, and 2023, respectively.

(3)This represents the estimated number of shares to be awarded as of December 31, 2023 as certain performance share measures have been achieved. Amounts are subject to change with final payout amounts authorized by the Board of Directors in February 2024.

The aggregate number of performance shares granted and outstanding at the target and maximum levels were as follows:

Performance share awards are based on the achievement of athree-year ROIC threshold that must be met and a cumulative EPS factor, which can be modified by a TSR factor relative to a specified peer group (2021-2023, 2022-2024, and 2023-2025 performance share awards) over thethree-year performance period. The performance period allows for one of the performance factors to remain variable until the first quarter of the third year of the award period. As the performance factor will not be approved until the first quarter of 2024 and 2025, there is not a mutual understanding of the awards' key terms and conditions between NW Natural and the participants as of December 31, 2023, and therefore, no expense was recognized for the 2022-2024 and 2023-2025 performance period. NW Natural will calculate the grant date fair value and recognize expense once the final performance factor has been approved. If the target is achieved for the 2022-2024 and 2023-2025 awards, NW Holdings would grant for accounting purposes 49,100 and 52,765 shares in the first quarter of 2024 and 2025, respectively.

Compensation expense is recognized in accordance with accounting standards for stock-based compensation and calculated based on performance levels achieved and an estimated fair value using the Monte-Carlo method. Due to there not being a mutual understanding of the 2022-2024 and 2023-2025 awards' key terms and conditions as noted above, the grant date fair value has not yet been determined andno non-vested shares existed at December 31, 2023. The weighted-average grant date fair value of non-vested shares associated with the 2021-2023 awards was $49.17 per share at December 31, 2023. The weighted-average grant date fair value of shares vested during the year was $49.17 per share and there wereno performance shares granted during the year andno unrecognized compensation expense for accounting purposes as of December 31, 2023.

Restricted Stock Units

In 2012, RSUs began being granted under the LTIP instead of stock options under the Restated SOP. Generally, the RSUs awarded are forfeitable and include a performance-based threshold as well as a vesting period offour years from the grant date. The majority of our RSU grants obligate NW Holdings, upon vesting, to issue the RSU holder one share of common stock. The grant may also include a cash payment equal to the total amount of dividends paid per share between the grant date and vesting date of that portion of the RSU depending on the structure of the award agreement. The fair value of an RSU is equal to the closing market price of NW Holdings' common stock on the grant date. During 2023, total RSU expense was $1.9 million compared to $2.1 million in 2022 and $2.0 million in 2021. As of December 31, 2023, there was $3.1 million of unrecognized compensation cost from grants of RSUs, which is expected to be recognized over a period extending through 2027.

Information regarding the RSU activity is summarized as follows:

Employee Stock Purchase Plan

NW Holdings' ESPP allows employees of NW Holdings, NW Natural and certain designated subsidiaries to purchase common stock at 85% of the closing price on the trading day immediately preceding the initial offering date, which is set annually. For the 2023-2024 ESPP period, each eligible employee may purchase up to $21,224 worth of stock through payroll deductions over a period defined by the Board of Directors, with shares issued at the end of the subscription period.

Stock-Based Compensation Expense

Stock-based compensation expense is recognized as operations and maintenance expense or is capitalized as part of construction overhead at the entity at which the award recipient is employed. The following table summarizes the NW Holdings' financial statement impact, substantially all of which was recorded at NW Natural, of stock-based compensation under the LTIP and ESPP:

9. DEBT

Short-Term Debt

The primary source of short-term liquidity for NW Holdings is cash balances, dividends from its operating subsidiaries, in particular NW Natural, available cash from a multi-year credit facility, and short-term credit facilities it may enter into from time to time.

The primary source of short-term liquidity for NW Natural is from the sale of commercial paper, available cash from a multi-year credit facility, and short-term credit facilities it may enter into from time to time. In addition to issuing commercial paper or entering into bank loans to meet working capital requirements, including seasonal requirements to finance gas purchases and accounts receivable, short-term debt may also be used to temporarily fund capital requirements. For NW Natural, commercial paper and bank loans are periodically refinanced through the sale of long-term debt or equity contributions from NW Holdings. Commercial paper, when outstanding, is sold through two commercial banks under an issuing and paying agency agreement and is supported by one or more unsecured revolving credit facilities. See “Credit Agreements” below.

At December 31, 2023 and 2022, NW Natural's short-term debt consisted of the following:

(1) Weighted average interest rate on outstanding short-term debt

The carrying cost of commercial paper approximates fair value using Level 2 inputs. See Note 2 for a description of the fair value hierarchy. At December 31, 2023, NW Natural's commercial paper had a maximum remaining maturity of 5 days and an average remaining maturity of 4 days.

Credit Agreements

In November 2021, NW Holdings entered into an amended and restated $200.0 million credit agreement, with a feature that allows NW Holdings to request increases in the total commitment amount, up to a maximum of $300.0 million. The maturity date of the agreement is November 3, 2026, with an available extension of commitments for two additionalone-year periods, subject to lender approval. Interest charges on the NW Holdings credit agreement were indexed to the London Interbank Offered Rate (LIBOR) through January 31, 2023. The agreement was amended to replace LIBOR with the secured overnight financing rate (SOFR) beginning February 2023. The SOFR is subject to a 10 basis point spread adjustment.

The NW Holdings credit agreement permits the issuance of letters of credit in an aggregate amount of up to $40.0 million. The principal amount of borrowings under the credit agreement is due and payable on the maturity date. The credit agreement requires NW Holdings to maintain a consolidated indebtedness to total capitalization ratio of 70% or less. Failure to comply with this covenant would entitle the lenders to terminate their lending commitments and accelerate the maturity of all amounts outstanding. NW Holdings was in compliance with this covenant at December 31, 2023 and 2022.

The NW Holdings credit agreement also requires NW Holdings to maintain debt ratings (which are defined by a formula using NW Natural's credit ratings in the event NW Holdings does not have a credit rating) with Standard & Poor's (S&P) and Moody's Investors Service, Inc. (Moody’s) and notify the lenders of any change in its senior unsecured debt ratings or senior secured debt ratings, as applicable, by such rating agencies. A change in NW Holdings' debt ratings by S&P or Moody’s is not an event of default, nor is the maintenance of a specific minimum level of debt rating a condition of drawing upon the credit agreement. Rather, interest rates on any loans outstanding under the credit agreements are tied to debt ratings and therefore, a change in the debt rating would increase or decrease the cost of any loans under the credit agreements when ratings are changed. NW Holdings maintains a credit rating with S&P of A+ and does not currently maintain ratings with Moody's.

There was $73.0 million and $88.0 million of outstanding balances under the NW Holdings agreement at December 31, 2023 and 2022, respectively. No letters of credit were issued or outstanding under the NW Holdings agreement at December 31, 2023 and 2022.

In November 2021, NW Natural entered into an amended and restated credit agreement for unsecured revolving loans totaling $400.0 million, with a feature that allows NW Natural to request increases in the total commitment amount, up to a maximum of $600.0 million. The maturity date of the agreement is November 3, 2026 with an available extension of commitments for two additionalone-year periods, subject to lender approval. The credit agreement permits the issuance of letters of credit in an aggregate amount of up to $60.0 million. The principal amount of borrowings under the credit agreement is due and payable on the maturity date. Interest charges on the NW Natural credit agreement were indexed to the LIBOR through January 31, 2023. The agreement was amended to replace LIBOR with the SOFR beginning February 2023. The SOFR is subject to a 10 basis point spread adjustment.

NW Natural's credit agreement requires NW Natural to maintain a consolidated indebtedness to total capitalization ratio of 70% or less. Failure to comply with this covenant would entitle the lenders to terminate their lending commitments and accelerate the maturity of all amounts outstanding. NW Natural was in compliance with this covenant at December 31, 2023 and 2022.

The NW Natural credit agreement also requires NW Natural to maintain credit ratings with S&P and Moody’s and notify the lenders of any change in NW Natural's senior unsecured debt ratings or senior secured debt ratings, as applicable, by such rating agencies. A change in NW Natural's debt ratings by S&P or Moody’s is not an event of default, nor is the maintenance of a specific minimum level of debt rating a condition of drawing upon the credit agreement. Rather, interest rates on any loans outstanding under the credit agreement are tied to debt ratings and therefore, a change in the debt rating would increase or decrease the cost of any loans under the credit agreement when ratings are changed.

There wasone letter of credit outstanding at December 31, 2023 under NW Natural's credit agreement andno letters of credit outstanding at December 31, 2022. In December 2023, NW Natural issued a $15 million letter of credit through its existing credit agreement, which expired January 5, 2024.

Letters of Credit Facility

In January 2024, NW Natural entered into an Uncommitted Letter of Credit and Reimbursement Agreement (LC Reimbursement Agreement), pursuant to which NW Natural agreed to reimburse each Lender acting as an issuing bank (Issuing Bank) thereunder for disbursements in respect of letters of credit (Letters of Credit) issued pursuant to the LC Reimbursement Agreement from time to time. The Company expects to use Letters of Credit issued under the facility created by the LC Reimbursement Agreement (LC Facility) primarily to support its participation in Washington Climate Commitment Act cap-and-invest program auctions.

Although there is no expressly stated maximum amount of Letters of Credit that can be issued or outstanding under the LC Facility, under current regulatory authority from the OPUC, the aggregate sum of Letters of Credit outstanding and available to be drawn under the LC Reimbursement Agreement may not exceed $100 million at any one time. The Issuing Banks have no commitment to issue Letters of Credit under the LC Facility and will have the discretion to limit and condition the terms for the issuance of Letters of Credit (including maximum face amounts) in their sole discretion.

The LC Reimbursement Agreement requires NW Natural to maintain certain ratings with S&P and Moody’s. NW Natural must also notify the Administrative Agent and Lenders of any change in the S&P or Moody’s Ratings, although any such change is not an event of default.

The LC Reimbursement Agreement prohibits NW Natural from permitting Consolidated Indebtedness to be greater than 70% of Total Capitalization, each as defined therein and calculated as of the end of each fiscal quarter of NW Natural. Failure to comply with this financial covenant would constitute an Event of Default under the LC Reimbursement Agreement. The occurrence of this or any other Event of Default would entitle the Administrative Agent to require cash collateral for the LC Exposure, as defined in the LC Reimbursement Agreement, and to exercise all other rights and remedies available to it and the Lenders under the Credit Documents, as defined in the LC Reimbursement Agreement, and under applicable law.

Long-Term Debt

At December 31, 2023 and 2022, NW Holdings long-term debt consisted of the following:

(1) Weighted average interest rate for the years ended December 31, 2023 and 2022.

NW Natural Long-Term Debt

NW Natural's issuance of First Mortgage Bonds (FMBs), which includes NW Natural's medium-term notes, under the Mortgage and Deed of Trust (Mortgage) is limited by eligible property, adjusted net earnings, and other provisions of the Mortgage. The Mortgage constitutes a first mortgage lien on certain gas properties owned from time to time by NW Natural, including substantially all of NW Natural's NGD property.

In August 2023, NW Natural issued and sold $80.0 million aggregate principal amount of its FMBs,5.18% Series and $50.0 million aggregate principal amount of its FMBs,5.23% Series. The 5.18% Bonds bear interest at the rate of 5.18% per annum, payable semi-annually on February 4 and August 4 of each year, commencing February 4, 2024, and will mature on August 4, 2034. The 5.23% Bonds bear interest at the rate of 5.23% per annum, payable semi-annually on February 4 and August 4 of each year, commencing February 4, 2024, and will mature on August 4, 2038.

In March 2023, NW Natural issued and sold $100.0 million aggregate principal amount of 5.75% Secured Medium-Term Notes, Series B due 2033 (the Notes). The Notes bear interest at the rate of 5.75% per annum, payable semi-annually on March 15 and September 15 of each year.

In January 2023, NW Natural issued and sold $100.0 million aggregate principal amount of its FMBs,5.43% Series due January 2053. The 5.43% Bonds bear interest at the rate of 5.43% per annum, payable semi-annually on January 6 and July 6 of each year, commencing July 6, 2023, and will mature on January 6, 2053.

NW Holdings Note Purchase Agreement

In December 2023, NW Holdings entered into a Note Purchase Agreement between NW Holdings and the institutional investors named as purchasers therein. The Note Purchase Agreement provides for the issuance of (i) $100.0 million aggregate principal amount of NW Holdings’5.78% Senior Notes, Series A, due March 7, 2028 (5.78% Notes) and (ii) $50.0 million aggregate principal amount of NW Holdings’5.84% Senior Notes, Series B, due March 7, 2029 (5.84% Notes) in reliance on an exemption from registration under Section 4(a)(2) of the Securities Act of 1933, as amended. The 5.78% Notes and the 5.84% Notes are expected to be issued on or about March 7, 2024, pursuant to the Note Purchase Agreement. The proceeds from the Note Purchase Agreement are expected to be used to refinance $150.0 million of existing term loans at NW Holdings and NWN Water.

The 5.78% Notes will bear interest at the rate of 5.78% per annum, payable semi-annually on March 7 and September 7 of each year, commencing September 9, 2024, and will mature on March 7, 2028. NW Holdings may, at its option, prepay at any time all, or from time to time any part of, the outstanding 5.78% Notes at a price equal to 100% of the principal amount thereof, plus a “make-whole” premium and accrued and unpaid interest thereon to the date of prepayment; provided, however, in the case of a partial prepayment, NW Holdings must prepay at least 5% of the aggregate principal amount of the 5.78% Notes outstanding. At any time on or after February 7, 2028, NW Holdings may, at its option, prepay all or any part of the 5.78% Notes at 100% of the principal amount thereof, plus accrued and unpaid interest thereon to the date of prepayment, but without the payment of a “make-whole” premium, so long as there is no Default or Event of Default under the Note Purchase Agreement.

The 5.84% Bonds will bear interest at the rate of 5.84% per annum, payable semi-annually on March 7 and September 7 of each year, commencing September 9, 2024, and will mature on March 7, 2029. NW Holdings may, at its option, prepay at any time all, or from time to time any part of, the outstanding 5.84% Notes at a price equal to 100% of the principal amount thereof, plus a “make-whole” premium and accrued and unpaid interest thereon to the date of prepayment; provided, however, in the case of a partial prepayment, NW Holdings must prepay at least 5% of the aggregate principal amount of the 5.84% Notes outstanding. At any time on or after February 7, 2029, NW Holdings may, at its option, prepay all or any part of the 5.84% Notes at 100% of the principal amount thereof, plus accrued and unpaid interest thereon to the date of prepayment, but without the payment of a “make-whole” premium, so long as there is no Default or Event of Default under the Note Purchase Agreement.

Interest Rate Swap Agreements

NW Holdings and NWN Water entered into interest rate swap agreements with major financial institutions that effectively convert variable-rate debt to a fixed rate. Interest payments made between the effective date and expiration date are hedged by the swap agreements. The notional amount, effective date, expiration date and benchmark rate of the swap agreements are shown in the table below:

Maturities and Outstanding Long-Term Debt

Retirement of long-term debt for each of the annual periods through December 31, 2028 and thereafter are as follows:

The following table presents debt outstanding at NW Natural as of December 31:

Fair Value of Long-Term Debt

NW Holdings' and NW Natural's outstanding debt does not trade in active markets. The fair value of debt is estimated using the value of outstanding debt at natural gas distribution companies with similar credit ratings, terms, and remaining maturities to NW Holdings' and NW Natural's debt that actively trade in public markets. Substantially all outstanding debt at NW Holdings is comprised of NW Natural debt. These valuations are based on Level 2 inputs as defined in the fair value hierarchy. See Note 2.

The following table provides an estimate of the fair value of long-term debt, including current maturities of long-term debt, using market prices in effect on the valuation date:

10. PENSION AND OTHER POSTRETIREMENT BENEFIT COSTS

NW Natural maintains a qualified non-contributory defined benefit pension plan (Pension Plan) for all eligible employees, non-qualified supplemental pension plans for eligible executive officers and other key employees, and other postretirement employee benefit plans. NW Natural also has a qualified defined contribution plan (Retirement K Savings Plan) for all eligible employees. The Pension Plan and Retirement K Savings Plan have plan assets, which are held in qualified trusts to fund retirement benefits.

Effective January 1, 2007 and 2010, the Pension Plan and postretirement benefits for non-union employees and union employees, respectively, were closed to new participants. Non-union and union employees hired or re-hired after December 31, 2006 and 2009, respectively, and employees of NW Natural subsidiaries are provided an enhanced Retirement K Savings Plan benefit.

The following table provides a reconciliation of the changes in NW Natural's benefit obligations and fair value of plan assets, as applicable, for NW Natural's pension and other postretirement benefit plans, excluding the Retirement K Savings Plan, and a summary of the funded status and amounts recognized in NW Holdings' and NW Natural's consolidated balance sheets as of December 31:

At December 31, 2023, the net liability (benefit obligations less market value of plan assets) for the Pension Plan increased $7.9 million compared to 2022. The increase in the net pension liability is primarily due to the $11.0 million increase to the pension benefit obligation, partially offset by the $3.1 million increase in plan assets. The liability for non-qualified plans increased $1.0 million, and the liability for other postretirement benefits increased $1.6 million in 2023.

NW Natural's Pension Plan had a projected benefit obligation of $392.6 million and $381.6 million at December 31, 2023 and 2022, respectively, and fair values of plan assets of $283.4 million and $280.3 million, respectively. The plan had an accumulated benefit obligation of $363.5 million and $353.4 million at December 31, 2023 and 2022, respectively.

The following table presents amounts realized through regulatory assets or in other comprehensive loss (income) for the years ended December 31:

The following table presents amounts recognized in regulatory assets and accumulated other comprehensive loss (AOCL) at December 31:

The following table presents amounts recognized by NW Holdings and NW Natural in AOCL and the changes in AOCL related to NW Natural's non-qualified employee benefit plans:

In 2024, NW Natural will amortize $5.2 million in estimated costs from regulatory assets to net periodic benefit costs.

The assumed discount rates for NW Natural's Pension Plan and other postretirement benefit plans were determined independently based on the FTSE Above Median Curve (discount rate curve), which uses high quality corporate bonds rated AA- or higher by S&P or Aa3 or higher by Moody’s. The discount rate curve was applied to match the estimated cash flows in each of the plans to reflect the timing and amount of expected future benefit payments for these plans.

The assumed expected long-term rate of return on plan assets for the Pension Plan was developed using a weighted-average of the expected returns for the target asset portfolio. In developing the expected long-term rate of return assumption, consideration was given to the historical performance of each asset class in which the plan’s assets are invested and the target asset allocation for plan assets.

The investment strategy and policies for Pension Plan assets held in the retirement trust fund were approved by the NW Natural Retirement Committee, which is composed of senior management with the assistance of an outside investment consultant. The policies set forth the guidelines and objectives governing the investment of plan assets. Plan assets are invested for total return with appropriate consideration for liquidity, portfolio risk, and return expectations. All investments are expected to satisfy the prudent investments rule under the Employee Retirement Income Security Act of 1974. The approved asset classes may include cash and short-term investments, fixed income, common stock and convertible securities, absolute and real return strategies, and real estate. Plan assets may be invested in separately managed accounts or in commingled or mutual funds. Investment re-balancing takes place periodically as needed, or when significant cash flows occur, in order to maintain the allocation of assets within the stated target ranges. The retirement trust fund for the Pension Plan is not currently invested in NW Holdings or NW Natural securities.

The following table presents the Pension Plan asset target allocation at December 31, 2023:

Non-qualified supplemental defined benefit plan obligations were $32.8 million and $31.8 million at December 31, 2023 and 2022, respectively. These plans are not subject to regulatory deferral, and the changes in actuarial gains and losses, prior service costs, and transition assets or obligations are recognized in AOCL, net of tax until they are amortized as a component of net periodic benefit cost. These are unfunded, non-qualified plans withno plan assets; however, a significant portion of the obligations is indirectly funded with company and trust-owned life insurance and other assets.

Other postretirement benefit plans are unfunded plans but are subject to regulatory deferral. The actuarial gains and losses, prior service costs, and transition assets or obligations for these plans are recognized as a regulatory asset.

Net periodic benefit costs consist of service costs, interest costs, the expected returns on plan assets, and the amortization of gains and losses and prior service costs. The gains and losses are the sum of the actuarial and asset gains and losses throughout the year and are amortized over the average remaining service period of active participants. The asset gains and losses are based in part on a market-related valuation of assets. The market-related valuation reflects differences between expected returns and actual investment returns with the differences recognized over a two-year period from the year in which they occur, thereby reducing year-to-year net periodic benefit cost volatility.

The service cost component of net periodic benefit cost for NW Natural pension and other postretirement benefit plans is recognized in operations and maintenance expense in the consolidated statements of comprehensive income. The other non-service cost components are recognized in other income (expense), net in the consolidated statements of comprehensive income. The following table provides the components of net periodic benefit cost for NW Natural's pension and other postretirement benefit plans for the years ended December 31:

Net periodic benefit costs are reduced by amounts capitalized to NGD plant. In addition, a certain amount of net periodic benefit costs were recorded to the regulatory balancing account, representing net periodic pension expense for the Pension Plan above the amount set in rates, as approved by the OPUC, from 2011 through October 31, 2018. Total amortization of the regulatory balancing account of $7.1 million was recognized in each of the years ended December 31, 2023 and 2022, of which $2.6 million was charged to operations and maintenance expense and $4.5 million was charged to other income (expense).

The following table provides the assumptions used in measuring periodic benefit costs and benefit obligations for the years ended December 31:

(1)Rate assumption ranges from 3.2% to 4.6% in 2024,4.7% to 5.8% in 2025 and 4.0% to 4.7% thereafter.

The assumed annual increase in health care cost trend rates used in measuring other postretirement benefits as of December 31, 2023 was 6.50%. These trend rates apply to both medical and prescription drugs. Medical costs and prescription drugs are assumed to decrease gradually each year to a rate of 4.00% by 2029.

Assumed health care cost trend rates can have a significant effect on the amounts reported for the health care plans; however, other postretirement benefit plans have a cap on the amount of costs reimbursable by NW Natural.

Mortality assumptions are reviewed annually and are updated for material changes as necessary. In 2023, mortality rate assumptions remained consistent with 2022, using Pri-2012 mortality tables using scale MP-2021.

The following table provides information regarding employer contributions and benefit payments for NW Natural's Pension Plan, non-qualified pension plans, and other postretirement benefit plans for the years ended December 31, and estimated future contributions and payments:

Employer Contributions to Company-Sponsored Defined Benefit Pension Plan

NW Natural makes contributions to its Pension Plan based on actuarial assumptions and estimates, tax regulations, and funding requirements under federal law. The American Rescue Plan, which was signed into law on March 11, 2021, includes a provision for pension relief that extends the amortization period for required contributions from 7 to 15 years and provides for the stabilization of interest rates used to calculate future required contributions. As a result, NW Natural madeno cash contributions to its Pension Plan for 2023.

The Pension Plan was underfunded by $109.2 million at December 31, 2023. During 2024, NW Natural expects to make cash contributions of approximately $20.6 million to the Pension Plan.

Multiemployer Pension Plan

In addition to the NW Natural-sponsored Pension Plan presented above, prior to 2014 NW Natural contributed to a multiemployer pension plan for its NGD union employees known as the Western States Office and Professional Employees International Union Pension Fund (Western States Plan). That plan's employer identification number is 94-6076144. Effective December 22, 2013, NW Natural withdrew from the plan, which was a noncash transaction. Vested participants will receive all benefits accrued through the date of withdrawal. As the plan was underfunded at the time of withdrawal, NW Natural was assessed a withdrawal liability of $8.3 million, plus interest, which requires NW Natural to pay $0.6 million each year to the plan for 20 years beginning in July 2014. The cost of the withdrawal liability was deferred to a regulatory account on the balance sheet.

Payments were $0.6 million for 2023, and as of December 31, 2023, the liability balance was $5.0 million. For 2022 and 2021, contributions to the plan were $0.6 million and $0.4 million, respectively, which was approximately 1% to 4% of the total contributions to the plan by all employer participants in those years.

Defined Contribution Plan

NW Natural's Retirement K Savings Plan is a qualified defined contribution plan under Internal Revenue Code Sections 401(a) and 401(k). NW Natural contributions totaled $10.4 million, $9.6 million, and $8.8 million for 2023, 2022, and 2021, respectively.

Deferred Compensation Plans

NW Natural's supplemental deferred compensation plans for eligible officers and senior managers are non-qualified plans. These plans are designed to enhance the retirement savings of employees and to assist them in strengthening their financial security by providing an incentive to save and invest regularly.

Below is a description of the valuation methodologies used for assets measured at fair value. In cases where NW Natural's Pension Plan is invested through a collective trust fund or mutual fund, the fund's market value is utilized. Market values for investments directly owned are also utilized.

U.S. EQUITY. These are non-published net asset value (NAV) assets. The non-published NAV assets consist of commingled trusts where NAV is not published but the investment can be readily disposed of at NAV or market value. The underlying investments in this asset class includes investments primarily in U.S. common stocks.

INTERNATIONAL/GLOBAL EQUITY. These are Level 1 and non-published NAV assets. The Level 1 asset is a mutual fund, and the non-published NAV assets consist of commingled trusts where the NAV/unit price is not published, but the investment can be readily disposed of at the NAV/unit price. The mutual fund has a readily determinable fair value, including a published NAV, and the commingled trusts are valued at unit price. This asset class includes investments primarily in foreign equity common stocks.

LIABILITY HEDGING. These are non-published NAV assets. The non-published NAV assets consist of commingled trusts where NAV is not published but the investment can be readily disposed of at NAV or market value. The underlying investments in this asset class include long duration fixed income investments primarily in U.S. treasuries, U.S. government agencies, municipal securities, mortgage-backed securities, asset-backed securities, as well as U.S. and international investment-grade corporate bonds.

OPPORTUNISTIC. These are non-published NAV assets. The non-published NAV assets consist of commingled trusts where NAV is not published but the investment can be readily disposed of at NAV or market value. The underlying investments in this asset class include real estate investment trust equities, high yield bonds, floating rate debt, emerging market debt and a commodity index pool.

CASH AND CASH EQUIVALENTS. These are non-published NAV assets. The non-published NAV assets represent mutual funds without published NAV's but the investment can be readily disposed of at the NAV. The mutual funds are valued at the NAV of the shares held by the plan at the valuation date.

The preceding valuation methods may produce a fair value calculation that is not indicative of net realizable value or reflective of future fair values. Although we believe these valuation methods are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain investments could result in a different fair value measurement at the reporting date.

Commingled trust investments are subject to a redemption notice period of five business days. There were no unfunded commitments for Plan investments as of December 31, 2023 and 2022.

Investment securities are exposed to various financial risks including interest rate, market, and credit risks. Due to the level of risk associated with certain investment securities, it is reasonably possible that changes in the values of NW Natural's investment securities will occur in the near term and such changes could materially affect NW Natural's investment account balances and the amounts reported as plan assets available for benefit payments.

The following tables present the fair value of NW Natural's Pension Plan assets, including outstanding receivables and liabilities, of NW Natural's retirement trust fund:

(1)The fair value for these investments is determined using Net Asset Value per share (NAV) as of December 31, as a practical expedient, and therefore they are not classified within the fair value hierarchy. These investments primarily consist of institutional investment products, for which the NAV is generally not publicly available.

11. INCOME TAX

The following table provides a reconciliation between income taxes calculated at the statutory federal tax rate and the provision for income taxes reflected in the NW Holdings and NW Natural statements of comprehensive income or loss for December 31:

The NW Holdings and NW Natural effective income tax rates for 2023 compared to 2022 changed primarily as a result of pre-tax income.

The NW Holdings and NW Natural effective income tax rates for 2022 compared to 2021 changed primarily due to lower income tax amortization in 2022 of the 2020 Oregon Corporate Activity Tax (CAT), which was subject to regulatory deferral when it became effective on January 1, 2020 and then amortized in income tax expense as recovery began in late 2020, 2021, and 2022.

The provision for current and deferred income taxes consists of the following at December 31:

The following table summarizes the tax effect of significant items comprising NW Holdings and NW Natural's deferred income tax balances recorded at December 31:

At December 31, 2023 and 2022, regulatory income tax assets of $8.0 million and $10.2 million, respectively, were recorded by NW Natural, a portion of which is recorded in current assets. These regulatory income tax assets primarily represent future rate recovery of deferred tax liabilities, resulting from differences in NGD plant financial statement and tax bases and NGD plant removal costs, which were previously flowed through for rate making purposes and to take into account the additional future taxes, which will be generated by that recovery. These deferred tax liabilities, and the associated regulatory income tax assets, are currently being recovered through customer rates. At December 31, 2023 and 2022, regulatory income tax assets of $4.9 million and $2.9 million, respectively, were recorded by NW Natural, representing future recovery of deferred tax liabilities resulting from the equity portion of AFUDC.

At December 31, 2023 and 2022, deferred tax assets of $46.1 million and $48.0 million, respectively, were recorded by NW Natural representing the future income tax benefit associated with the excess deferred income tax regulatory liability recorded as a result of the lower federal corporate income tax rate provided for by the TCJA. At December 31, 2023 and 2022, regulatory liability balances representing the benefit of the change in deferred taxes as a result of the TCJA of $174.2 million and $181.4 million, respectively, were recorded by NW Natural.

NW Holdings and NW Natural assess the available positive and negative evidence to estimate if sufficient taxable income will be generated to utilize their respective existing deferred tax assets. Based upon this assessment, NW Holdings and NW Natural determined that it is more likely than not that all of their respective deferred tax assets recorded as of December 31, 2023 will be realized.

The Company estimates it has net operating loss (NOL) carryforwards of $29 thousand for federal taxes and $29 thousand for state taxes at December 31, 2023. The federal NOLs do not expire and we anticipate fully utilizing the state NOL carryforward balances before they begin to expire in 2040. California alternative minimum tax (AMT) credits of $56 thousand are also available. The AMT credits do not expire.

Uncertain tax positions are accounted for in accordance with accounting standards that require an assessment of the anticipated settlement outcome of material uncertain tax positions taken in a prior year, or planned to be taken in the current year. Until such positions are sustained, the uncertain tax benefits resulting from such positions would not be recognized. No reserves for uncertain tax positions were recorded as of December 31, 2023, 2022, or 2021.

The federal income tax returns for tax years 2019 and earlier are closed by statute. The IRS Compliance Assurance Process (CAP) examination of the 2020 and 2021 tax years have been completed. There were no material changes to these returns as filed. The 2022 and 2023 tax years are currently under IRS CAP examination. The 2024 CAP application has been filed. Under the CAP program, NW Holdings and NW Natural work with the IRS to identify and resolve material tax matters before the tax return is filed each year.

As of December 31, 2023, income tax years 2019 through 2022 remain open for examination by the States of California and Texas. Income tax years 2020 through 2022 are open for examination by the States of Arizona, Idaho, Nebraska, and Oregon.

12. PROPERTY, PLANT, AND EQUIPMENT

The following table sets forth the major classifications of property, plant, and equipment and accumulated depreciation of continuing operations at December 31:

Accumulated depreciation does not include the accumulated provision for asset removal costsof$496.2 million and $467.7 million at December 31, 2023 and 2022, respectively. These accrued asset removal costs are reflected on the balance sheet as regulatory liabilities. See Note 2.

Other plant balances include long-lived assets associated with water and wastewater operations and non-regulated activities not held by NW Natural or its subsidiaries.

Other plant balances include non-utility gas storage assets at the Mist facility and other long-lived assets not related to NGD.

The weighted average depreciation rate for NGD assets was 3.0% in 2023, 2022, and 2021. The weighted average depreciation rate for assets not related to NGD was 1.7% in 2023 and 1.8% in 2022 and 2021.

13. INVESTMENTS

Investments include gas reserves, financial investments in life insurance policies, and equity method investments. The following table summarizes other investments at December 31:

Investment in Life Insurance Policies

NW Natural has invested in key person life insurance contracts to provide an indirect funding vehicle for certain long-term employee and director benefit plan liabilities. The amount in the above table is reported at cash surrender value, net of policy loans.

NW Natural Gas Reserves

NW Natural has invested $188 million through the gas reserves program in the Jonah Field located in Wyoming as of December 31, 2023. Gas reserves are stated at cost, net of regulatory amortization, with the associated deferred tax benefits of $4.0 million and $5.2 million, which are recorded as liabilities in the December 31, 2023 and 2022 consolidated balance sheets, respectively. NW Natural's investment is included in NW Holdings' and NW Natural's consolidated balance sheets under other current assets and other investments (non-current portion) with the maximum loss exposure limited to the investment balance. The amount of gas reserves included in other current assets was $2.3 million and $3.4 million as of December 31, 2023 and 2022, respectively. The investment in gas reserves provides long-term price protection and acted to hedge the cost of gas for approximately 3% and 3% of NGD gas supplies for the years ended December 31, 2023 and 2022, respectively.

Investments in Unconsolidated Affiliates

In December 2021, NWN Water purchased a 37.3% ownership stake in Avion Water Company, Inc. (Avion Water), an investor-owned water utility for $14.5 million. In July 2022 and June 2023, NWN Water increased its ownership stake in Avion Water to 43.1% for an additional $1.0 million in each period. In January 2024, NWN Water increased its ownership stake in Avion Water to 45.6% for an additional $1.0 million. Avion Water operates in Bend, Oregon and the surrounding communities, serving approximately 15,000 customer connections and employing 35 people. The carrying value of the equity method investment is $8.6 million higher than the underlying equity in the net assets of the investee at December 31, 2023 due to equity method goodwill. Equity in earnings (loss) of Avion Water is included in other income (expense), net.

In 2020, NW Natural began a partnership with BioCarbN to invest in up tofour separate renewable natural gas (RNG) development projects that are designed to access biogas derived from water treatment at Tyson Foods’ processing plants, subject to approval by all parties. During the construction phase of the projects, NW Natural determined it is the primary beneficiary and fully consolidates each entity. In January 2022, commissioning of the first project, Lexington Renewable Energy LLC (Lexington), was completed. NW Natural determined it was no longer the primary beneficiary, deconsolidated the variable interest entity and recorded the investment in Lexington as an equity method investment. As of December 31, 2023, NW Natural had an investment balance in Lexington of $7.6 million. NW Natural's share in the earnings (loss) of Lexington is included in cost of gas.

In April 2023, commissioning of the second project, Dakota City Renewable Energy LLC (Dakota City), was completed. NW Natural determined it was no longer the primary beneficiary of Dakota City once the project was commissioned. The investment in the variable interest entity was deconsolidated and recorded as an equity method investment. NW Natural accounts for its interest in Dakota City using the equity method of accounting because NW Natural does not control but has the ability to exercise significant influence over Dakota City's operations after commissioning. There wasno gain or loss recognized upon deconsolidation. NW Natural determined the fair value of the investment approximated the carrying value which was primarily comprised of cash and property, plant and equipment. As of December 31, 2023, NW Natural had an investment balance in Dakota City of $11.9 million. NW Natural's share in the earnings (loss) of Dakota City is included in cost of gas.

In January 2024, NW Natural replaced BioCarbN as manager of the Lexington and Dakota City projects.

14. BUSINESS COMBINATIONS

2023 Business Combinations

During the year ended December 31, 2023, NWN Water and its subsidiaries acquired the assets offive businesses qualifying as business combinations. The aggregate fair value of the preliminary total consideration transferred for these acquisitions was $22.8 million, most of which was preliminarily allocated to property, plant, and equipment, and goodwill. These transactions align with NW Holdings' water and wastewater sector strategy as it continues to expand its water and wastewater service territories and included:

•Pedersen Family, LLC in Washington

•King Water Corporation in Washington

•Rose Valley Water Company in Arizona

•Hiland Water in Oregon

•Truxton and Cerbat in Arizona

Intangible Assets

In connection with the acquisition of King Water Corporation, NWN Water recorded long-term customer relationship intangible assets totaling $2.6 million, which will be amortized over 24 years. There wasno amortization expense recognized in 2023. Projected amortization expense at NW Holdings for customer relationship intangible assets for each of the next five years is $0.1 million in each period. The amortization will change in future periods if other intangible assets are acquired, impairments are recognized or the preliminary valuations as part of our purchase price allocation is refined.

2022 Business Combinations

Far West Water & Sewer, Inc.

On October 5, 2022, NWN Water completed the acquisition of the water and wastewater utilities of Far West Water & Sewer, Inc. (Far West), which has a combined approximately 25,000 connections in Yuma, Arizona. The acquisition-date fair value of the total consideration transferred, after closing adjustments, was approximately $97.0 million, of which $88.4 million was cash consideration transferred at closing, $8.1 million was contingent consideration, and $0.5 million was deferred consideration.

The contingent consideration is an earnout payment in an amount equal to the product of (i) the amount, if any, by which the average annual System Operating Revenue for the 2026, 2027, and 2028 years exceeds $13.0 million (ii) multiplied by 4 but shall not exceed $12.0 million. As of the acquisition date, the contingent consideration had a fair value of $8.1 million and was included in other non-current liabilities. The fair value as of the acquisition date was determined using a scenario-based technique using management's best estimate of forecast revenue for the years 2026, 2027, and 2028 discounted to present value. The inputs to determine the fair value of the contingent consideration include estimated future revenue and a risk-adjusted discount rate. The fair value measurement is based on significant inputs that are not observable in the market and thus represents a fair value measurement categorized within Level 3 of the fair value hierarchy per ASC Topic 820.

The Far West acquisition met the criteria of a business combination, and as such an allocation of the consideration to the acquired net assets based on their estimated fair value as of the acquisition date was performed. In accordance with U.S. GAAP, the fair value determination involves management judgment in determining the significant estimates and assumptions used and was made using existing regulatory conditions for net assets associated with Far West. The acquisition costs were expensed as incurred.

Goodwill of $69.9 million was recognized from this acquisition. The goodwill recognized is attributable to Far West's regulated water utility service territory, experienced workforce, and the strategic benefits for both the water utility and wastewater services expected from growth in its service territory. No intangible assets aside from goodwill were recognized. The amount of goodwill that is expected to be deductible for income tax purposes is approximately $63.3 million.

The purchase price for the acquisition has been allocated to the net assets acquired as of the acquisition date and is as follows:

The amount of Far West revenues included in NW Holdings' consolidated statements of comprehensive income is $2.9 million for the year ended December 31, 2022. Earnings from Far West activities for the year ended December 31, 2022 were not material to the results of NW Holdings. Far West is referred to as Foothills Utilities following the closure of the acquisition.

Other 2022 Business Combinations

During the year ended December 31, 2022, NWN Water and its subsidiaries acquired the assets ofsix additional businesses qualifying as business combinations. The aggregate fair value of the consideration transferred for these acquisitions was $8.7 million, most of which was allocated to property, plant and equipment and goodwill. These transactions align with NW Holdings' water and wastewater sector strategy as it continues to expand its water and wastewater service territories and included:

•Belle Oaks Water and Sewer Co., Inc in Texas

•Northwest Water Services, LLC in Washington

•Aquarius Utilities, LLC in Washington

•Valiant Idaho, LLC (The Idaho Club - Sewer) in Idaho

•Caney Creek in Texas

•Water Necessities, Inc. and Rural Water Co. in Texas

2021 Business Combinations

During the year ended December 31, 2021, NWN Water and its subsidiaries completed four acquisitions qualifying as business combinations. The aggregate fair value of the consideration transferred for these acquisitions were not material and are not significant to NW Holdings' results of operations.

Goodwill

NW Holdings allocates goodwill to reporting units based on the expected benefit from the business combination. We perform an annual impairment assessment of goodwill at the reporting unit level, or more frequently if events and circumstances indicate that goodwill might be impaired. An impairment loss is recognized if the carrying value of a reporting unit’s goodwill exceeds its fair value.

As a result of all acquisitions completed, total goodwill was $163.3 million as of December 31, 2023 and $149.3 million as of December 31, 2022. The increase in the goodwill balance was primarily due to additions associated with our acquisitions in the water and wastewater sector. All of our goodwill is related to water and wastewater acquisitions and is included in the other category for segment reporting purposes. The annual impairment assessment of goodwill occurs in the fourth quarter of each year. There have beenno impairments recognized to date.

15. DERIVATIVE INSTRUMENTS

NW Natural enters into financial derivative contracts to hedge a portion of the NGD segment’s natural gas sales requirements. These contracts include swaps, options, and option combinations. These derivative financial instruments are primarily used to manage commodity price variability. A small portion of NW Natural's derivative hedging strategy involves foreign currency forward contracts.

NW Natural enters into these financial derivatives, up to prescribed limits, primarily to hedge price variability related to term physical gas supply contracts. The foreign currency forward contracts are used to hedge the fluctuation in foreign currency exchange rates for pipeline demand charges paid in Canadian dollars.

In the normal course of business, NW Natural also enters into indexed-price physical forward natural gas commodity purchase contracts and options to meet the requirements of NGD customers. These contracts qualify for regulatory deferral accounting treatment.

Notional Amounts

The following table presents the absolute notional amounts related to open positions on NW Natural derivative instruments:

Purchased Gas Adjustment (PGA)

Rates and hedging approaches may vary between states due to different rate structures and mechanisms. Under the PGA mechanism in Oregon, derivatives entered into by NW Natural for the procurement or hedging of natural gas for future gas years generally receive regulatory deferral accounting treatment. In general, commodity hedging for the current gas year is completed prior to the start of the gas year, and hedge prices are reflected in the weighted-average cost of gas in the PGA filing. Hedge contracts entered into after the start of the PGA period are subject to the PGA incentive sharing mechanism in Oregon. Under the PGA mechanism in Washington, NW Natural incorporates a risk-responsive hedging strategy, and receives regulatory deferral accounting treatment for its Washington gas supplies.

NW Natural entered the 2022-23 gas year with total forecasted sales volumes hedged at approximately 84%, including 67% in financial hedges and 17% in physical gas supplies. The total hedged was approximately 85% in Oregon and 79% in Washington. NW Natural entered the 2023-24 gas year with total forecasted sales volume hedged atapproxima tely 82%, including 66% in financial hedges and 16% in physical gas supplies. The total hedged was approximately 85% in Oregon and 55% in Washington.

Unrealized and Realized Gain/Loss

The following table reflects the income statement presentation for the unrealized gains and losses from NW Natural's derivative instruments:

Unrealized Gain/Loss

Outstanding derivative instruments related to regulated NGD operations are deferred in accordance with regulatory accounting standards. The cost of foreign currency forward and natural gas derivative contracts are recognized immediately in the cost of gas; however, costs above or below the amount embedded in the current year PGA are subject to a regulatory deferral tariff and therefore, are recorded as a regulatory asset or liability.

Realized Gain/Loss

NW Natural realized a net gain of $125.5 million and $107.8 million for the years ended December 31, 2023 and 2022, respectively, from the settlement of natural gas financial derivative contracts. Realized gains and losses offset the higher or lower cost of gas purchased, resulting in no incremental amounts to collect or refund to customers.

Credit Risk Management of Financial Derivatives Instruments

No collateral was posted with or by NW Natural counterparties as of December 31, 2023 or 2022. NW Natural attempts to minimize the potential exposure to collateral calls by diversifying counterparties and using credit limits to manage liquidity risk. Counterparties generally allow a certain credit limit threshold before requiring NW Natural to post collateral against unrealized loss positions. Given NW Natural's credit ratings, counterparty credit limits and portfolio diversification, it was not subject to collateral calls in 2023 or 2022. The collateral call exposure is set forth under credit support agreements, which generally contain credit limits. NW Natural could also be subject to collateral call exposure where it has agreed to provide adequate assurance, which is not specific as to the amount of credit limit allowed, but could potentially require additional collateral posting by NW Natural in the event of a material adverse change.

NW Natural's financial derivative instruments are subject to master netting arrangements; however, they are presented on a gross basis in the consolidated balance sheets. NW Natural and its counterparties have the ability to set-off obligations to each other under specified circumstances. Such circumstances may include a defaulting party, a credit change due to a merger affecting either party, or any other termination event.

If netted by counterparty, NW Natural's physical and financial derivative position would result in an asset of $9.0 million and a liability of $124.2 million as of December 31, 2023, and an asset of $153.3 million and a liability of $3.6 million as of December 31, 2022.

NW Natural is exposed to derivative credit and liquidity risk primarily through securing fixed-price natural gas commodity swaps and interest rate swaps with financial counterparties. NW Natural utilizes master netting arrangements with International Swaps and Derivatives Association (ISDA) contracts to minimize these risks including ISDA Credit Support Agreements with counterparties based on their credit ratings. Additionally, NW Natural uses counterparty, industry, sector and country diversification to minimize credit risk. In certain cases, NW Natural may require counterparties to post collateral, guarantees, or letters of credit to maintain its minimum credit requirement standards or for liquidity management purposes.

NW Natural's financial derivatives policy requires counterparties to have an investment-grade credit rating at the time the derivative instrument is entered into, and specifies limits on the contract amount and duration based on each counterparty’s credit rating. NW Natural does not speculate in derivatives. Derivatives are used to manage NW Natural's market risk and we hedge exposure above risk tolerance limits. It is required that increases in market risk created by the use of derivatives is offset by the exposures they modify.

We actively monitor NW Natural's derivative credit exposure and place counterparties on hold for trading purposes or require other forms of credit assurance, such as letters of credit, cash collateral, or guarantees as circumstances warrant. The ongoing assessment of counterparty credit risk includes consideration of credit ratings, credit default swap spreads, bond market credit spreads, financial conditions, government actions, and market news. A Monte Carlo simulation model is used to estimate the change in credit and liquidity risk from the volatility of natural gas prices. The results of the model are used to establish trading limits. NW Natural's outstanding financial derivatives at December 31, 2023 mature by November 1, 2026.

We could become materially exposed to credit risk with one or more of our counterparties if natural gas prices experience a significant increase. If a counterparty were to become insolvent or fail to perform on its obligations, we could suffer a material loss; however, we would expect such a loss to be eligible for regulatory deferral and rate recovery, subject to a prudence review. All of our existing counterparties currently have investment-grade credit ratings.

In accordance with fair value accounting, NW Natural includes non-performance risk in calculating fair value adjustments. This includes a credit risk adjustment based on the credit spreads of NW Natural counterparties when in an unrealized gain position, or on NW Natural's own credit spread when it is in an unrealized loss position. The inputs in our valuation models include natural gas futures, volatility, credit default swap spreads, and interest rates. Additionally, the assessment of non-performance risk is generally derived from the credit default swap market and from bond market credit spreads. The impact of the credit risk adjustments for all financial derivatives outstanding to the fair value calculation was $0.7 million at December 31, 2023. As of December 31, 2023 and 2022, the net fair value was a liability of $115.2 million and an asset of $149.7 million, respectively, using significant other observable, or Level 2, inputs. No Level 3 inputs were used in our derivative valuations during the years ended December 31, 2023 and 2022.

NW Holdings and NWN Water entered into interest rate swap agreements with major financial institutions that effectively converted variable-rate debt to a fixed rate. Interest payments made between the effective date and expiration date are hedged by the swap agreements. The notional amount, effective date, expiration date and benchmark rate of the swap agreements are shown in the table below:

Unrealized gains and losses related to these interest rate swap agreements are recorded in AOCI on the consolidated balance sheet and totaled $0.2 million and $0.1 million, net of tax, as of December 31, 2023 and 2022, respectively. There wereno amounts reclassified from AOCI to net income during the year ended December 31, 2023 and 2022.

16. COMMITMENTS AND CONTINGENCIES

Gas Purchase Agreements

NW Natural enters into short-term and long-term physical baseload gas purchase agreements. The majority of our gas purchase agreements include year-round, winter-only, summer-only, and monthly purchases.

Pipeline Capacity Purchase and Release Commitments

NW Natural has signed agreements providing for the reservation of firm pipeline capacity under which it is required to make monthly payments for contracted capacity. The pricing component of the monthly payment is established, subject to change, by U.S. or Canadian regulatory bodies, or is established directly with private counterparties, as applicable. In addition, NW Natural has entered into long-term agreements to release firm pipeline capacity. The parties that we release this capacity to make payments directly to the related pipelines.

The aggregate amounts of these agreements at NW Natural were as follows at December 31, 2023:

(1)Gas purchase agreements include environmental attributes of RNG.

Total fixed charges under capacity purchase agreements were $87.0 million for 2023, $90.2 million for 2022, and $82.9 million for 2021, of which $8.2 million, $8.3 million, and $7.7 million, respectively, related to capacity releases which third parties paid directly to the related pipelines. In addition, per-unit charges are required to be paid based on the actual quantities shipped under the agreements. In certain take-or-pay purchase commitments, annual deficiencies may be offset by prepayments subject to recovery over a longer term if future purchases exceed the minimum annual requirements.

Leases

Refer to Note 7 for a discussion of lease commitments and contingencies.

Environmental Matters

Refer to Note 17 for a discussion of environmental commitments and contingencies.

17. ENVIRONMENTAL MATTERS

NW Natural owns, or previously owned, properties that may require environmental remediation or action. The range of loss for environmental liabilities is estimated based on current remediation technology, enacted laws and regulations, industry experience gained at similar sites, and an assessment of the probable level of involvement and financial condition of other potentially responsible parties (PRPs). When amounts are prudently expended related to site remediation of those sites described herein, NW Natural has recovery mechanisms in place to collect 96.7% of remediation costs allocable to Oregon customers and 3.3% of costs allocable to Washington customers.

These sites are subject to the remediation process prescribed by the Environmental Protection Agency (EPA) and the Oregon Department of Environmental Quality (ODEQ). The process begins with a remedial investigation (RI) to determine the nature and extent of contamination and then a risk assessment (RA) to establish whether the contamination at the site poses unacceptable risks to humans and the environment. Next, a feasibility study (FS) or an engineering evaluation/cost analysis (EE/CA) evaluates various remedial alternatives. It is at this point in the process when NW Natural is able to estimate a range of remediation costs and record a reasonable potential remediation liability, or make an adjustment to the existing liability. From this study, the regulatory agency selects a remedy and issues a Record of Decision (ROD). After a ROD is issued, NW Natural would seek to negotiate a consent decree or consent judgment for designing and implementing the remedy. NW Natural would have the ability to further refine estimates of remediation liabilities based upon an approved remedial design.

Remediation may include treatment of contaminated media such as sediment, soil and groundwater, removal and disposal of media, institutional controls such as legal restrictions on future property use, or natural recovery. Following construction of the remedy, the EPA and ODEQ also have requirements for ongoing maintenance, monitoring and other post-remediation care that may continue for many years. Where appropriate and reasonably known, NW Natural will provide for these costs in the remediation liabilities described below.

Due to the numerous uncertainties surrounding the course of environmental remediation and the preliminary nature of several site investigations, in some cases, NW Natural may not be able to reasonably estimate the high end of the range of possible loss. In those cases, the nature of the possible loss has been disclosed, as has the fact that the high end of the range cannot be reasonably estimated where a range of potential loss is available. Unless there is an estimate within the range of possible losses that is more likely than other cost estimates within that range, NW Natural records the liability at the low end of this range. It is likely changes in these estimates and ranges will occur throughout the remediation process for each of these sites due to the continued evaluation and clarification concerning responsibility, the complexity of environmental laws and regulations and the determination by regulators of remediation alternatives. In addition to remediation costs, NW Natural could also be subject to

Natural Resource Damages (NRD) claims. NW Natural will assess the likelihood and probability of each claim and recognize a liability if deemed appropriate. Refer to "Other Portland Harbor" below.

Environmental Sites

The following table summarizes information regarding liabilities related to environmental sites, which are recorded in other current liabilities and other noncurrent liabilities in NW Natural's balance sheet at December 31:

Portland Harbor Site

The Portland Harbor is an EPA listed Superfund site that is approximately 10 miles long on the Willamette River and is adjacent to NW Natural's Gasco uplands site. NW Natural is one of overone hundred PRPs, each jointly and severally liable, at the Superfund site. In January 2017, the EPA issued its Record of Decision, which selects the remedy for the clean-up of the Portland Harbor site (Portland Harbor ROD). The Portland Harbor ROD estimates the present value total cost at approximately $1.05 billion with an accuracy between -30% and +50% of actual costs.

NW Natural's potential liability is a portion of the costs of the remedy for the entire Portland Harbor Superfund site. The cost of that remedy is expected to be allocated among more than one hundred PRPs. NW Natural is participating in a non-binding allocation process with other PRPs in an effort to resolve its potential liability. The Portland Harbor ROD does not provide any additional clarification around allocation of costs among PRPs; accordingly, NW Natural has not modified any of the recorded liabilities at this time as a result of the issuance of the Portland Harbor ROD.

NW Natural manages its liability related to the Superfund site astwo distinct remediation projects, the Gasco Sediments Site and Other Portland Harbor projects.

GASCO SEDIMENTS. In 2009, NW Natural and Siltronic Corporation entered into a separate Administrative Order on Consent with the EPA to evaluate and design specific remedies for sediments adjacent to the Gasco uplands and Siltronic uplands sites. NW Natural submitted a draft EE/CA to the EPA in May 2012 to provide the estimated cost of potential remedial alternatives for this site. In March 2020, NW Natural and the EPA amended the Administrative Order on Consent to include additional remedial design activities downstream of the Gasco sediments site and in the navigation channel. Siltronic Corporation is not a party to the amended order. NW Natural is completing pre-design studies and has submitted a draft Basis of Design Report. These preliminary design steps do not include a cost estimate for cleanup. No remedial design is more likely than the EE/CA alternatives at this time, and NW Natural expects further design discussion and iteration with the EPA.

The estimated costs for the various sediment remedy alternatives in the draft EE/CA for the additional studies and design work needed before the cleanup can occur, and for regulatory oversight throughout the cleanup range from $55.0 million to $350 million. NW Natural has recorded a liability of $55.0 million for the Gasco sediment clean-up, which reflects the low end of the range. At this time, we believe sediments at the Gasco sediments site represent the largest portion of NW Natural's liability related to the Portland Harbor site discussed above.

In September 2023, the EPA approved the In Situ Stabilization and Solidification (ISS) Work Plan for the ISS field pilot study, which was successfully completed during the fall of 2023. Information obtained from the pilot study will be used to support remedial design of the Gasco sediments project.

OTHER PORTLAND HARBOR. While we believe liabilities associated with the Gasco sediments site represent NW Natural's largest exposure, there are other potential exposures associated with the Portland Harbor ROD, including NRD costs and harborwide remedial design and cleanup costs (including downstream petroleum contamination), for which allocations among the PRPs have not yet been determined.

NW Natural and other parties have signed a cooperative agreement with the Portland Harbor Natural Resource Trustee council to participate in a phased NRD assessment to estimate liabilities to support an early restoration-based settlement of NRD claims. One member of this Trustee council, the Yakama Nation, withdrew from the council in 2009, and in 2017, filed suit against NW Natural and 29 other parties seeking remedial costs and NRD assessment costs associated with the Portland Harbor site, set forth in the complaint. The complaint seeks recovery of alleged costs totaling$0.3 millionin connection with the selection of a remedial action for the Portland Harbor site as well as declaratory judgment for unspecified future remedial action costs and for costs to assess the injury, loss or destruction of natural resources resulting from the release of hazardous substances at and from the Portland Harbor site. The Yakama Nation has filedtwo amended complaints addressing certain pleading defects and dismissing the State of Oregon. On the motion of NW Natural and certain other defendants the federal court has stayed the case pending the outcome of the non-binding allocation proceeding discussed above. NW Natural has recorded a liability for NRD claims which is at the low end of the range of the potential liability; the high end of the range cannot be reasonably estimated at this time. The NRD liability is not included in the aforementioned range of costs provided in the Portland Harbor ROD.

Gasco Uplands Site

A predecessor of NW Natural, Portland Gas and Coke Company, owned a former gas manufacturing plant that was closed in 1958 (Gasco site) and is adjacent to the Portland Harbor site described above. The Gasco site has been under investigation by NW Natural for environmental contamination under the ODEQ Voluntary Cleanup Program (VCP). It is not included in the range of remedial costs for the Portland Harbor site noted above. The Gasco site is managed in two parts, the uplands portion and the groundwater source control action.

NW Natural submitted a revised Remedial Investigation Report for the uplands to ODEQ in May 2007. In March 2015, ODEQ approved the Risk Assessment (RA) for this site, enabling commencement of work on the FS in 2016. A draft FS is currently anticipated to be submitted in 2024. NW Natural has recognized a liability for the remediation of the uplands portion of the site which is at the low end of the range of potential liability; the high end of the range cannot be reasonably estimated at this time.

In October 2016, ODEQ and NW Natural agreed to amend their VCP agreement for the Gasco uplands to incorporate a portion of the Siltronic property formerly owned by Portland Gas & Coke between 1939 and 1960 into the Gasco RA and FS. Previously, NW Natural was conducting an investigation of manufactured gas plant constituents on the entire Siltronic uplands for ODEQ. Siltronic will be working with ODEQ directly on environmental impacts to the remainder of its property.

In September 2013, NW Natural completed construction of a groundwater source control system, including a water treatment station, at the Gasco site. NW Natural has estimated the cost associated with the ongoing operation of the system and has recognized a liability which is at the low end of the range of potential cost. NW Natural cannot estimate the high end of the range at this time due to the uncertainty associated with the duration of running the water treatment station, which is highly dependent on the remedy determined for both the upland portion as well as the final remedy for the Gasco sediments site.

Other Sites

In addition to those sites above, NW Natural has environmental exposures at three other sites: Central Service Center, Front Street and Oregon Steel Mills. NW Natural may have exposure at other sites that have not been identified at this time. Due to the uncertainty of the design of remediation, regulation, timing of the remediation and in the case of the Oregon Steel Mills site, pending litigation, liabilities for each of these sites have been recognized at their respective low end of the range of potential liability; the high end of the range could not be reasonably estimated at this time.

FRONT STREET SITE. The Front Street site was the former location of a gas manufacturing plant NW Natural operated (the former Portland Gas Manufacturing site, or PGM). At ODEQ’s request, NW Natural conducted a sediment and source control investigation and provided findings to ODEQ. In December 2015, an FS on the former Portland Gas Manufacturing site was completed.

In July 2017, ODEQ issued the PGM ROD. The ROD specifies the selected remedy, which requires a combination of dredging, capping, treatment, and natural recovery. In addition, the selected remedy also requires institutional controls and long-term inspection and maintenance. Construction of the remedy began in July 2020 and was completed in October 2020. The first year of post-construction monitoring was completed in 2021 and demonstrated that the cap was intact and performing as designed. NW Natural has recognized an additional liability of $1.6 million for costs associated with the discovery during construction of World War II-era munitions, design costs, regulatory and permitting issues, and post-construction work.

OREGON STEEL MILLS SITE. Refer to “Legal Proceedings,” below.

Environmental Cost Deferral and Recovery

NW Natural has authorizations in Oregon and Washington to defer costs related to remediation of properties that are owned or were previously owned by NW Natural. In Oregon, a Site Remediation and Recovery Mechanism (SRRM) is currently in place to recover prudently incurred costs allocable to Oregon customers, subject to an earnings test. On October 21, 2019 the WUTC authorized an Environmental Cost Recovery Mechanism (ECRM) for recovery of prudently incurred costs allocable to Washington customers beginning November 1, 2019.

The following table presents information regarding the total regulatory asset deferred as of December 31:

(1) Includes pre-review and post-review deferred costs, amounts currently in amortization, and interest, net of amounts collected from customers.

(2)Excludes 3.3% of the Front Street site liability as the OPUC only allows recovery of 96.7% of costs for those sites allocable to Oregon, including those that historically served only Oregon customers. Amounts excluded from regulatory assets were$53 thousand in 2023 and $43 thousand in 2022.

(3)Environmental costs relate to specific sites approved for regulatory deferral by the OPUC and WUTC. In Oregon, NW Natural earns a carrying charge on cash amounts paid, whereas amounts accrued but not yet paid do not earn a carrying charge until expended. It also accrues a carrying charge on insurance proceeds for amounts owed to customers. In Washington, neither the cash paid nor insurance proceeds received accrue a carrying charge. Current environmental costs represent remediation costs management expects to collect from customers in the next 12 months. Amounts included in this estimate are still subject to a prudence and earnings test review by the OPUC and do not include the $5.0 million tariff rider. The amounts allocable to Oregon are recoverable through NGD rates, subject to an earnings test. See "Oregon SRRM" below.

Oregon SRRM

Collections From Oregon Customers

Under the SRRM collection process, there are three types of deferred environmental remediation expense:

•Pre-review - This class of costs represents remediation spend that has not yet been deemed prudent by the OPUC. Carrying costs on these remediation expenses are recorded at NW Natural's authorized cost of capital. NW Natural anticipates the prudence review for annual costs and approval of the earnings test prescribed by the OPUC to occur by the third quarter of the following year.

•Post-review - This class of costs represents remediation spend that has been deemed prudent and allowed after applying the earnings test, but is not yet included in amortization. NW Natural earns a carrying cost on these amounts at a rate equal to the five-year treasury rate plus 100 basis points.

•Amortization - This class of costs represents amounts included in current customer rates for collection and is generally calculated as one-fifth of the post-review deferred balance. NW Natural earns a carrying cost equal to the amortization rate determined annually by the OPUC, which approximates a short-term borrowing rate.

In addition to the collection amount noted above, an order issued by the OPUC provides for the annual collection of $5.0 million from Oregon customers through a tariff rider. As NW Natural collects amounts from customers, it recognizes these collections as revenue and separately amortizes an equal and offsetting amount of its deferred regulatory asset balance through the environmental remediation operating expense line shown separately in the operating expense section of the income statement.

NW Natural received total environmental insurance proceeds of approximately $150 million as a result of settlements from litigation that was dismissed in July 2014. Under a 2015 OPUC order which established the SRRM, one-third of the Oregon allocated proceeds were applied to costs deferred through 2012 with the remaining two-thirds applied to costs at a rate of $5.0 million per year plus interest over the following 20 years. NW Natural accrues interest on the Oregon allocated insurance proceeds in the customer’s favor at a rate equal to the five-year treasury rate plus 100 basis points. As of December 31, 2023, NW Natural has applied $100.7 million of insurance proceeds to prudently incurred remediation costs allocated to Oregon.

Environmental Earnings Test

To the extent NW Natural earns at or below its authorized Return on Equity (ROE) as defined by the SRRM, remediation expenses and interest in excess of the $5.0 million tariff rider and $5.0 million insurance proceeds are recoverable through the SRRM. To the extent NW Natural earns more than its authorized ROE in a year, it is required to cover environmental expenses and interest on expenses greater than the $10.0 million with those earnings that exceed its authorized ROE.

Washington ECRM

Washington Deferral

On October 21, 2019, the WUTC issued an order (WUTC Order) establishing the ECRM which allows for recovery of past deferred and future prudently incurred environmental remediation costs allocable to Washington customers through application of insurance proceeds and collections from customers. Environmental remediation expenses relating to sites that previously served both Oregon and Washington customers are allocated between states with Washington customers receiving 3.3% percent of the costs and insurance proceeds.

In accordance with the WUTC Order, insurance proceeds were fully applied to costs incurred between December 2018 and June 2019 that were deemed prudent. Remaining insurance proceeds will be amortized over a 10.5 year period ending December 31,

2029. As of December 31, 2023, approximately $3.9 million of proceeds have been applied to prudently incurred costs.

On an annual basis, NW Natural files for a prudence determination and a request to amortize costs to the extent that remediation expenses exceed the insurance amortization. After insurance proceeds are fully amortized, if in a particular year the request to collect deferred amounts exceeds one percent of Washington normalized revenues, then the excess will be collected over three years with interest.

NW Holdings is not currently party to any direct claims or litigation, though in the future it may be subject to claims and litigation arising in the ordinary course of business.

NW Natural is subject to claims and litigation arising in the ordinary course of business, including the matters discussed above. Although the final outcome of any of these legal proceedings cannot be predicted with certainty, including the matter relating to the Oregon Steel Mills site referenced below, NW Natural and NW Holdings do not expect that the ultimate disposition of any of these matters will have a material effect on their financial condition, results of operations, or cash flows. See also Part II, Item 1, “Legal Proceedings".

Oregon Steel Mills Site

In 2004, NW Natural was served with a third-party complaint by the Port of Portland (the Port) in a Multnomah County Circuit Court case, Oregon Steel Mills, Inc. v. The Port of Portland. The Port alleges that in the 1940s and 1950s petroleum wastes generated by NW Natural's predecessor, Portland Gas & Coke Company, and 10 other third-party defendants, were disposed of in a waste oil disposal facility operated by the United States or Shaver Transportation Company on property then owned by the Port and now owned by Evraz Oregon Steel Mills. The complaint seeks contribution for unspecified past remedial action costs incurred by the Port regarding the former waste oil disposal facility as well as a declaratory judgment allocating liability for future remedial action costs. No date has been set for trial. In August 2017, the case was stayed pending the outcome of the Portland Harbor allocation process or other mediation. Although the final outcome of this proceeding cannot be predicted with certainty, NW Natural and NW Holdings do not expect the ultimate disposition of this matter will have a material effect on NW Natural's or NW Holdings' financial condition, results of operations, or cash flows.

SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF NORTHWEST NATURAL HOLDING COMPANY

CONDENSED STATEMENTS OF COMPREHENSIVE INCOME

CONDENSED BALANCE SHEETS

CONDENSED STATEMENTS OF CASH FLOWS

NOTES TO CONDENSED FINANCIAL STATEMENTS

1. BASIS OF PRESENTATION

NW Holdings is an energy services holding company that conducts substantially all of its business operations through its subsidiaries, particularly NW Natural. These condensed financial statements and related footnotes have been prepared in accordance with Rule 12-04, Schedule I of Regulation S-X. These financial statements should be read in conjunction with the consolidated financial statements and notes thereto of NW Holdings included in Item 8 of this Form 10-K. NW Holdings' wholly-owned subsidiaries are recorded based upon its proportionate share of the subsidiaries' net assets (similar to presenting them on the equity method).

Equity earnings of subsidiaries including earnings from NW Natural were $106.3 million, $92.7 million, and $83.1 million for the years ended December 31, 2023, 2022, and 2021 respectively.

There were $95.7 million, $62.7 million and $82.1 million of cash dividends paid to NW Holdings from wholly-owned subsidiaries for the years ended December 31, 2023, 2022 and 2021, respectively.

2. DEBT

For information concerning NW Holdings' debt obligations, see Note 9 to the consolidated financial statements included in Item 8 of this report.

SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS AND RESERVES

SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS AND RESERVES