Northwest Natural Holding Co

1. ORGANIZATION AND PRINCIPLES OF CONSOLIDATION

The accompanying consolidated financial statements represent the respective, consolidated financial results of Northwest Natural Holding Company (NW Holdings) and Northwest Natural Gas Company (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 NWN Gas Utility reportable segment, which was previously referred to as the natural gas distribution (NGD) segment in prior periods. The NWN Gas Utility segment serves residential, commercial, and industrial customers in Oregon and southwest Washington. SiEnergy Operating, LLC (SiEnergy Gas Utility or SiEnergy), which was acquired January 7, 2025, is a regulated natural gas distribution utility and serves residential and commercial customers in the greater metropolitan areas of Houston, Dallas, and Austin, Texas. SiEnergy also includes a regulated natural gas transmission utility serving customers in the greater metropolitan areas of Dallas and Austin, Texas. SiEnergy activities are reported in the SiEnergy Gas Utility reportable segment. NW Natural Water Company, LLC (NWN Water Utility or NWN Water) activities are reported in the NWN Water Utility reportable segment, which provides water distribution and wastewater services to communities throughout the Pacific Northwest, Texas, Arizona, and California. NW Holdings and NW Natural also have investments and business activities not specifically related to the NWN Gas Utility, SiEnergy Gas Utility and NWN Water Utility segments, which are aggregated and reported as NW Holdings Other and NW Natural Other.

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. 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.

Information presented in these interim consolidated financial statements is unaudited, but includes all material adjustments management considers necessary for a fair statement of the results for each period reported including normal recurring accruals. These consolidated financial statements should be read in conjunction with the audited consolidated financial statements and related notes included in NW Holdings' and NW Natural's combined Annual Report on Form 10-K for the year ended December 31, 2024 (2024 Form 10-K). A significant part of NW Holdings' and NW Natural's business is of a seasonal nature; therefore, NW Holdings and NW Natural results of operations for interim periods are not necessarily indicative of full year results. Seasonality affects the comparability of the results of other operations across quarters but not across years.

Notes to the consolidated financial statements reflect the activity for both NW Holdings and NW Natural for all periods presented, unless otherwise noted. NW Holdings and NW Natural historical segment reporting has been recast to reflect their current organizational structure. The recasting did not have a material effect on the consolidated financial statements of NW Holdings or NW Natural.

2. SIGNIFICANT ACCOUNTING POLICIES

Significant accounting policies are described in Note 2 of the 2024 Form 10-K. There were no material changes to those accounting policies during the three months ended March 31, 2025 other than those set forth in this Note 2. The following are updates to certain critical accounting policy estimates and new accounting standards.

Industry Regulation

NW Holdings' principal business is to operate as a holding company for NW Natural, SiEnergy, NWN Water and its other subsidiaries. NW Natural's principal business is the distribution of natural gas, which is regulated by the Oregon Public Utility Commission (OPUC) and Washington Utilities and Transportation Commission (WUTC). NW Natural also has natural gas storage services, which are regulated by the Federal Energy Regulatory Commission (FERC), and to a certain extent by the OPUC and WUTC. SiEnergy's principal business is the distribution of natural gas in Texas; primarily in the Houston, Dallas and Austin metropolitan areas. SiEnergy also includes a regulated natural gas transmission utility serving customers in the greater metropolitan areas of Dallas and Austin, Texas. SiEnergy's natural gas utilities are subject to regulation by the Railroad Commission of Texas. NWN Water's principal business is water and wastewater utility services. NWN Water's 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 deferred as regulatory assets and liabilities for NW Holdings and NW Natural 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 NWN Gas Utility 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)Energy efficiency program for industrial sales customers in Oregon to provide assistance with reducing their gas usage.

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

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

(8)Estimated costs of removal on certain regulated properties are collected through rates.

We believe all costs incurred and deferred at March 31, 2025 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.

Supplemental Cash Flow Information

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. As of March 31, 2025, the amount invested in money market funds was $68.1 million at NW Natural and NW Holdings. As of March 31, 2024, the amount invested in money market funds was $48.8 million at NW Natural and NW Holdings. These investments are measured using net asset value per share.

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.

The following table provides a reconciliation of the cash, cash equivalents and restricted cash balances at NW Holdings as of March 31, 2025 and 2024 and December 31, 2024:

The following table provides a reconciliation of the cash, cash equivalents and restricted cash balances at NW Natural as of March 31, 2025 and 2024 and December 31, 2024:

Accounts Receivable and Allowance for Uncollectible Accounts

NW Holdings receivable balances primarily consist of trade receivables for the sale of natural gas and natural gas transportation services from NW Natural and SiEnergy and water sales and waste water services from NWN Water. These businesses establish an allowance for uncollectible accounts (allowance) for trade receivables, including accrued unbilled revenue, based on the age of receivable balances, collection experience of past due balances and payment plans, and historical trends of write-offs. 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.

NW Natural's allowance for residential and commercial trade receivables utilizes a method of 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.

NWN Water and SiEnergy follow methodologies that also review for historical write-off trends, the aging of the receivable balances, and collection experience. These businesses also monitor for impacts of economic conditions including the price of natural gas or water as appropriate, the economy and the impact on customers ability to pay.

The following table presents the activity related to the NW Holdings provision for uncollectible accounts by pool:

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.

Greenhouse Gas Allowances

WASHINGTON. NW Natural is subject to greenhouse gas (GHG) emission reduction requirements under the Washington Climate Commitment Act (CCA) regulations. 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 March 31, 2025 and 2024, NW Natural had $49.0 million and $39.5 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. As of March 31, 2025, NW Natural consigned no-cost allowances to Washington auctions and has received a total of $28.5 million 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 $36.0 million and $24.0 million liability as of March 31, 2025 and 2024. A portion of the costs to comply with the Washington program are currently being recovered from utility customers through rates beginning January 1, 2024. NW Natural recognized $36.0 million and $24.0 million of deferred costs as of March 31, 2025 and 2024.

OREGON. In November 2024, the Environmental Quality Commission adopted the Climate Protection Program (CPP). The CPP sets enforceable and declining limits, or caps, on GHG emissions from fossil fuels used throughout Oregon. The first compliance period started January 1, 2025 and covers emissions through the end of 2027.

New Accounting Standards

NW Holdings and NW Natural 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. We adopted the standard in January 2025. The adoption of this standard did not have an 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 an impact on our results of operations, liquidity or capital resources.

DISAGGREGATION OF EXPENSE DISCLOSURES. In November 2024, the FASB issued ASU 2024-03, which requires additional disclosures of disaggregated income statement expenses. The disclosures are required beginning with our annual report for the year ending December 31, 2027. The FASB issued ASU 2025-01 on January 6, 2025, to amend the effective date language of ASU 2024-03 clarifying that all public business entities are required to adopt the guidance in annual reporting periods beginning after December 15, 2026, and interim periods within annual reporting periods beginning after December 15, 2027. ASU 2025-01 did not impact the effective date of ASU 2024-03 for NW Holdings and NW Natural. The adoption of this standard is not anticipated to have an impact on our results of operations, liquidity, or capital resources.

Recent Securities and Exchange Commission (SEC) Final Rules

CLIMATE CHANGE. In March 2024, the SEC issued a final rule under SEC Release Nos. 33-11275 and 34-99678, The Enhancement and Standardization of Climate-Related Disclosures for Investors, which requires registrants to provide climate disclosures in their annual reports. Under the final rule, disclosures are required beginning with our annual report for the year ending December 31, 2025. In April 2024, the SEC voluntarily stayed implementation of the climate rule pending completion of judicial review of challenges to the rules consolidated in the Eighth Circuit Court of Appeals. On March 27, 2025, the SEC announced that it had voted to end its defense of the final rule. On April 25, 2025, the Eighth Circuit suspended the litigation challenging the final rule.

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

Prior to the first quarter of 2025, NW Holdings and NW Natural primarily operated inone reportable business segment, which was NW Natural's local gas distribution business, referred to as the NGD segment. NW Holdings and NW Natural also had investments and business activities not specifically related to the NGD segment, which were aggregated and reported as other.

During the first quarter of 2025, we evaluated the reportable business segments of NW Holdings and concluded that SiEnergy and NWN Water were also reportable business segments. In addition, the NGD segment was renamed to NWN Gas Utility. NW Holdings and NW Natural also have investments and business activities not specifically related to the NWN Gas Utility, SiEnergy, and NWN Water segments, which are aggregated and reported as NW Holdings Other. NW Holdings and NW Natural historical segment reporting has been recast to reflect their current organizational structure.

NW Holdings primarily operates inthree reportable business segments, which are NWN Gas Utility, SiEnergy, and NWN Water. NW Natural primarily operates inone reportable business segment, which is NWN Gas Utility. NW Holdings and NW Natural also have investments and business activities not specifically related to the reportable business segments, which are aggregated and reported as other and described below for each entity.

NWN Gas Utility

NW Natural's local gas distribution segment is a regulated utility servicing customers in Oregon and southwest Washington. In addition to NW Natural's local gas distribution business, the NWN Gas Utility segment also includes the portion of the Mist underground storage facility used to serve its customers, the North Mist gas storage expansion in Oregon, 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. NWN Gas Utility segment does not include Interstate Storage Services and third-party asset management services, and appliance retail center operations which are reported in NW Natural Gas Other and included in NW Holdings Other.

SiEnergy Gas Utility

SiEnergy Gas Utility is a regulated natural gas distribution utility, serving customers in the greater metropolitan areas of Houston, Dallas, and Austin, Texas. SiEnergy also includes a regulated natural gas transmission utility serving customers in the greater metropolitan areas of Dallas and Austin, Texas.

NWN Water Utility

NWN Water Utility is a regulated water and wastewater utility serving residential and commercial customers in Oregon, Washington, Idaho, Texas, and Arizona. NWN Water also includes non-regulated wastewater utilities and water services businesses in Oregon, Washington and Idaho, and an equity method investment in Avion Water Company, Inc. (a regulated entity). In addition, NWN Water provides water services to communities throughout the Pacific Northwest and California.

NW Holdings Other

NW Holdings' activities in Other includes activities of NW Natural Renewables Holdings, LLC (NWN Renewables), which is engaged in non-regulated renewable natural gas activities; NNG Financial and its pipeline assets; and NWN Energy including its wholly owned subsidiary NW Natural Gas Storage, LLC (NWN Gas Storage), which was formerly involved in a gas storage business. Other also includes corporate revenues and expenses that cannot be allocated to other operations, including certain business development activities. NW Holdings Other also includes NW Natural Gas Other activities which includes activities in Interstate Storage Services and third-party asset management services, appliance retail center operations, and corporate operating and non-operating revenues and expenses that cannot be allocated to NWN Gas Utility operations.

Segment Information Summary

Inter-segment transactions were immaterial for the periods presented. Total assets by segment is not regularly provided to the Chief Operating Decision Maker (CODM) and is therefore omitted. The following table presents summary financial information concerning the reportable segments and other:

(1)Income (loss) from operations is not a financial measure used by the CODM for NWN Gas Utility, but is included in the table above to enable the reconciliation of NWN Gas Utility margin to consolidated income before taxes in accordance with ASU 2023-07.

NW Holdings and NW Natural's CODM is the chief executive officer. The CODM uses NWN Gas Utility margin, SiEnergy margin and NWN Water income from operations to allocate resources, predominantly in the annual budget and forecasting process. The CODM considers budget-to-actual variances on a monthly basis when making decisions about allocating capital and personnel. The CODM also uses NWN Gas Utility margin, SiEnergy margin and NWN Water income from operations to assess the performance of NWN Gas Utility, SiEnergy and NWN Water, respectively.

NWN Gas Utility Margin

NWN Gas Utility margin is the primary financial measure used by the CODM, consisting of NWN Gas Utility operating revenues, reduced by the associated cost of gas, environmental remediation expense, and revenue taxes. The cost of gas purchased for NWN Gas Utility customers is generally a pass-through cost in the amount of revenues billed to regulated NWN Gas Utility 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 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 NWN Gas Utility operating revenues, NWN Gas Utility margin provides a key metric used by the CODM in assessing the performance of the NWN Gas Utility segment.

The following table presents additional segment information concerning NWN Gas Utility margin:

SiEnergy Gas Utility Margin

SiEnergy Gas Utility margin is the primary financial measure used by the CODM, consisting of SiEnergy operating revenues, reduced by the associated cost of gas and revenue taxes. The cost of gas purchased for SiEnergy customers is generally a pass-through cost in the amount of revenues billed to regulated SiEnergy customers. Revenue taxes are collected from 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 and revenue taxes from SiEnergy operating revenues, SiEnergy margin provides a key metric used by the CODM in assessing the performance of the segment.

The following table presents additional segment information concerning SiEnergy margin:

Significant Segment Expenses

Public entities are required to disclose significant segment expenses for each reportable segment if they are regularly provided to the CODM and included in the reported measure of segment profit/loss. This requirement does not necessitate additional disclosure for the NWN Gas Utility and SiEnergy segments, as all expense categories are presented above in the NWN Gas Utility margin table and SiEnergy margin table, respectively. Significant segment expenses for NWN Water are presented below.

(1)Other operating expenses include general and revenue taxes and other expenses.

5. COMMON STOCK

In August 2021, NW Holdings initiated an at-the-market (ATM) equity program by entering into an equity distribution agreement under which NW Holdings issued and sold from time to time shares of common stock, no par value, having an aggregate gross sales price of up to $200 million. In August 2024, the Finance Committee of the NW Holdings' Board of Directors authorized NW Holdings' sale of an additional $200 million in the aggregate gross sales price under the ATM equity program, with the result that a total of $400 million in the aggregate gross sales price has been authorized for issuance and sale under the ATM equity program. NW Holdings is under no obligation to offer and sell common stock under the ATM equity program, which the Finance Committee of the NW Holdings' Board of Directors has authorized through August 2027. Any shares of common stock offered under the ATM equity program are registered on NW Holdings’ universal shelf registration statement filed with the SEC, which expires in August 2027, or will be registered on a subsequent registration statement to be filed by NW Holdings.

During the three months ended March 31, 2025, NW Holdings issued and sold 22,954 shares of common stock pursuant to the ATM equity program resulting in cash proceeds of $1.0 million, net of fees and commissions paid to agents of $10 thousand. As of March 31, 2025, NW Holdings had $150.6 million of equity available for issuance under the ATM equity program. The ATM equity program was initiated to raise funds for general corporate purposes, including equity contributions to NW Holdings’ subsidiaries. Contributions to subsidiaries will be used for general corporate purposes.

6. REVENUE

The following tables present disaggregated revenue of NW Holdings:

(1) Prior year comparative disaggregated revenues are not provided for SiEnergy as it was acquired by NW Holdings January 7, 2025.

The following tables present disaggregated revenue of NW Natural:

NW Natural's revenue represents substantially all of NW Holdings' revenue and is recognized 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 contains one 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 utility customers and remitted to taxing authorities.

Components of Revenue

The components of NW Holdings' revenue, by reportable business segment, are explained below.

NWN Gas Utility

Natural Gas Sales

NW Natural's primary source of revenue is providing natural gas to customers in the NWN Gas Utility service territory, which includes residential, commercial, industrial and transportation customers. NWN Gas Utility 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. 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.

Customer accounts are to be paid in full each month and there is no significant financing component for this source of revenue. 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 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 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.

SiEnergy Gas Utility

SiEnergy Gas Utility's primary source of revenue is providing natural gas to customers in the SiEnergy service territory, which includes residential and commercial customers. SiEnergy 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 Texas tariff. There isno right of return or warranty for services provided.

Customer accounts are to be paid in full each month and there is no significant financing component for this source of revenue. Due to the election of the right to invoice practical expedient, we do not disclose the value of unsatisfied performance obligations.

NWN Water Utility

NWN Water Utility provides 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 states we operate. There isno right of return or warranty for services provided.

Customer accounts are to be paid in full each month, bi-monthly, or quarterly and as such, there is no significant financing component for this source of revenue. Due to the election of the right to invoice practical expedient, we do not disclose the value of unsatisfied performance obligations.

NW Holdings Other

Renewable Natural Gas Sales

NWN Renewables is an unregulated subsidiary of NW Holdings established to pursue investments in renewable natural gas (RNG) activities. NWN Renewables' primary source of revenue is from the sale of RNG under long-term contracts. RNG revenue is generally recognized over time upon delivery of the gas commodity to the customer at the designated delivery point and the amount of consideration received and recognized as revenue is dependent on a variable pricing model defined per the contract. Customer accounts are to be paid in full each month and as such, there is no significant financing component for this source of revenue. Due to the election of the right to invoice practical expedient, we do not disclose the value of unsatisfied performance obligations.

NW Natural 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 NWN Gas Utility customers.

NW Natural Asset Management Revenue

Revenues include the optimization of storage assets and pipeline capacity by a third-party and are provided net of the profit sharing amount refunded to NWN Gas Utility 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 March 31, 2025, unrecognized revenue for the fixed component of the transaction price related to gas storage and asset management revenue was approximately $119.3 million. Of this amount, approximately $20.0 million will be recognized during the remainder of 2025, $22.8 million in 2026, $17.2 million in 2027, $13.9 million in 2028, $13.9 million in 2029 and $31.5 million thereafter. The amounts presented here are calculated using current contracted rates.

NW Natural 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.

The components of NW Natural's revenue are described above in NWN Gas Utility and NW Holdings Other.

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 other immaterial sales type leases that are subject to an OPUC approved rate schedule. None of these other leases have variable payments or residual value guarantees and no significant selling profit upon lease commencement.

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 Holdings and 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 Holdings and NW Natural were as follows:

Lease revenue related to operating leases associated with NW Holdings non-utility property rentals was $0.2 million and $0.1 million for the three months ended March 31, 2025 and 2024. This lease revenue is 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 March 31, 2025 are as follows:

The total leases receivable above is reported under the NWN Gas Utility 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 $6.1 million, $5.6 million and $6.0 million at March 31, 2025 and 2024 and December 31, 2024, 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 of 2 months to 15 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.

NW Holdings assumed eight leases in connection with the SiEnergy acquisition. The leases primarily relate to office space, warehouse facilities, and land use agreements supporting the operations of SiEnergy. The assumed leases resulted in an increase of $2.3 million to both the operating lease right of use asset and operating lease liabilities recognized by NW Holdings. No finance type leases were assumed as part of the acquisition. The assumed lease balances are reflected in the disclosures and financial statements of NW Holdings as of March 31, 2025. Refer to Note 14 for additional information.

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

Supplemental balance sheet information related to operating leases as of March 31, 2025 and 2024 and December 31, 2024 is as follows:

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

As part of the SiEnergy acquisition, NW Holdings assumed operating leases with a weighted-average remaining lease term of 5.0 years and a weighted-average discount rate of 6.1%.

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 deferred regulatory asset on our balance sheet. The balance of the regulatory asset was $9.2 million, $8.3 million and $9.0 million as of March 31, 2025 and 2024 and December 31, 2024, respectively.

Maturities of operating lease liabilities at March 31, 2025 were as follows:

Supplemental cash flow information related to leases was as follows:

(1) Includes $2.3 million of non-cash operating lease right of use asset and operating lease liabilities recognized as part of the SiEnergy acquisition.

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 assets for finance leases were $3.1 million, $2.7 million and $3.0 million at March 31, 2025 and 2024 and at December 31, 2024, respectively.

8. STOCK-BASED COMPENSATION

Stock-based compensation plans are designed to promote stock ownership in NW Holdings by employees, including officers. These compensation plans include a Long Term Incentive Plan (LTIP) and an Employee Stock Purchase Plan (ESPP). For additional information on stock-based compensation plans, see Note 8 in the 2024 Form 10-K and the updates provided below.

Long Term Incentive Plan

Performance Shares

LTIP performance shares incorporate a combination of market, performance, and service-based factors. During the three months ended March 31, 2025, the final performance factor under the 2023-2025 LTIP was approved and 43,978 performance-based shares were granted under the 2023-2025 LTIP for accounting purposes. As such, NW Natural began recognizing compensation expense.

In February 2024, LTIP shares were awarded to participants; however, the agreement 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 2026, there is not a mutual understanding of the awards' key terms and conditions between NW Holdings and the participants as of March 31, 2025, and therefore, no expense was recognized for the 2024-2026 award. NW Holdings will calculate the grant date fair value and the applicable subsidiaries of NW Holdings will recognize expense over the remaining service period for each award once the final performance factor has been approved.

In February 2025, LTIP shares were awarded to certain participants; however, the agreement 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 2027, there is not a mutual understanding of the awards' key terms and conditions between NW Holdings and the participants as of March 31, 2025, and therefore, no expense was recognized for the 2025-2027 award. NW Holdings will calculate the grant date fair value and the applicable subsidiaries of NW Holdings will recognize expense over the remaining service period for each award once the final performance factor has been approved.

For the 2024-2026 and 2025-2027 LTIP awards, share payouts range from a threshold of 0% to a maximum of 200% based on achievement of pre-established goals. The performance criteria for the 2024-2026 and 2025-2027 performance shares consists of a three-year Return on Invested Capital (ROIC) threshold that must be satisfied and a cumulative EPS factor, which can be modified by a total shareholder return factor (TSR modifier) relative to the performance of peer group companies over the performance period ofthree years for each respective award. If the targets were achieved for the 2024-2026 and 2025-2027 awards, NW Holdings would grant for accounting purposes 73,150 and 76,500 shares in the first quarters of 2026 and 2027, respectively.

In February 2025,6,135 LTIP shares were awarded to certain participants. The LTIP awards share payouts range from a threshold of 0% to a maximum of 200% based on achievement of pre-established goals. The performance criteria for the 2025-2027 performance shares consist of a three-year ROIC threshold that must be satisfied and a 3-year cumulative EBITDA, which can be modified by a TSR modifier relative to the performance peer group companies over the period group.

As of March 31, 2025, there was $0.5 million of unrecognized compensation, which is expected to be recognized through 2027.

Restricted Stock Units

During the three months ended March 31, 2025,67,149 RSUs were granted under the LTIP with a weighted-average grant date fair value of $41.68 per share. Generally, the RSUs awarded are forfeitable and include a performance-based threshold as well as a vesting period of three 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.

As of March 31, 2025, there was $5.2 million of unrecognized compensation cost from grants of RSUs, which is expected to be recognized over a period extending through 2028.

9. DEBT

Short-Term Debt

At March 31, 2025, March 31, 2024 and December 31, 2024, short-term debt consisted of the following:

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

Commercial Paper Programs

On March 21, 2025, NW Holdings initiated a commercial paper program. At March 31, 2025, there wasno commercial paper outstanding at NW Holdings or NW Natural.

SiEnergy Revolving Credit Facility

On January 7, 2025, NW Holdings acquired all of the issued and outstanding limited liability company interest of SiEnergy. SiEnergy's subsidiary, Si Investment Co., has a revolving credit facility (the Revolving Facility) and a term loan credit facility (the Delayed Draw Term Loan Facility) under its Credit Agreement dated December 22, 2020 between SiEnergy, its subsidiaries Si Investment Co, LLC (Si Investment Co), SiEnergy, L.P., Terra Transmission, LLC, SiEnergy Power Solutions, LLC, and SiEnergy GP, L.L.C., and ING Capital LLC, as administrative agent and L/C Issuer (as defined therein), and the lenders party thereto (as amended, the Amended Credit Agreement). The Delayed Draw Term Loan Facility is described below in the Long-Term Debt section. The Revolving Facility has commitments in the aggregate of $5.0 million, including a letter of credit sublimit of $1.0 million. Si Investment Co is required to pay upfront fees, structuring fees, annual administrative fees, commitment fees, letter of credit fees and certain other fees. Loans extended under the Revolving Facility bear interest at a per annum rate equal to the sum of (a) either (i) the Base Rate, as defined in the Amended Credit Agreement (the Base Rate), or (ii) term SOFR with a one-, three- or six-month tenor; plus (b) the Applicable Margin. The Applicable Margin is 0.750% with respect to Base Rate loans and 1.750% with respect to SOFR loans. At March 31, 2025, there wereno borrowings on the Revolving Facility.

Acquisition Bridge Facility

On January 7, 2025, NW Holdings entered into a 364-Day Term Loan Credit Agreement (the Acquisition Bridge Facility) among NW Holdings, as borrower, certain lenders parties thereto, and JPMorgan Chase Bank, N.A., as Administrative Agent, pursuant to which NW Holdings borrowed a $273.0 million senior unsecured term loan (the Bridge Loan), the proceeds of which were used to finance the SiEnergy acquisition, with any remaining proceeds to be used for working capital needs and for general corporate purposes. The Bridge Loan was repaid in full in March 2025.

Long-Term Debt

At March 31, 2025, March 31, 2024 and December 31, 2024, NW Holdings' long-term debt consisted of the following:

(1) Weighted average interest rate for the three months ended March 31, 2025 and March 31, 2024

(2) Weighted average interest rate for the year ended December 31, 2024

(3) On January 7, 2025, NW Holdings acquired SiEnergy. SiEnergy's subsidiary, Si Investment Co., had this existing term loan facility outstanding at the date of acquisition.

NW Natural's first mortgage bonds (FMBs) have maturity dates ranging from 2025 through 2053 and interest rates ranging from 2.82% to 7.85%. NW Holdings' unsecured senior bonds have maturity dates ranging from 2028 through 2034 and interest rates ranging from 5.52% to 5.86%. NWN Water's term loan is due in 2026. In March 2024, NW Holdings retired a $100.0 million credit agreement and NWN Water retired a $50.0 million credit agreement. As of March 31, 2025, $30.0 million of debt is scheduled to mature in the next twelve months at NW Natural and $6.8 million of debt is scheduled to mature in the next twelve months at NW Holdings Other.

SiEnergy Delayed Draw Term Loan Facility

On January 7, 2025, NW Holdings acquired all of the issued and outstanding limited liability company interest of SiEnergy. SiEnergy's subsidiary, Si Investment Co., has a term loan credit facility (the Delayed Draw Term Loan Facility), on a delayed draw basis, which had initial aggregate commitments, as amended, of $200.0 million, of which $33.3 million remained in effect as of March 31, 2025. As of March 31, 2025, the outstanding principal balance of the Delayed Draw Term Loan Facility is $149.6 million.

Loans extended under the Delayed Draw Term Loan Facility bear interest at a per annum rate equal to the sum of (a) either (i) the Base Rate, as defined in the Amended Credit Agreement (the Base Rate), or (ii) term SOFR with a one-, three- or six-month tenor; plus (b) the Applicable Margin. The Applicable Margin is 0.750% with respect to Base Rate loans and 1.750% with respect to SOFR loans.

Loans borrowed under the Delayed Draw Term Loan Facility from time to time become funded term loans (Funded Term Loans), which are subject to required amortization, once per year. Si Investment Co. is required to make principal payments with respect to Funded Term Loans in equal quarterly installments in an amount sufficient to amortize such loans over a period of 25 years. In addition, the Delayed Draw Term Loan Facility is subject to certain mandatory prepayments, including in connection with certain asset sales or casualty or that result in Loan Parties’ receipt of certain insurance or condemnation proceeds. The Delayed Draw Term Loan Facility matures on December 22, 2026.

Issuance of Long-Term Debt

On January 6, 2025, NW Holdings entered into a Term Loan Credit Agreement (the Term Loan Agreement), among NW Holdings, as borrower, certain lenders parties thereto, and U.S. Bank National Association, as Administrative Agent, pursuant to which NW Holdings borrowed a $50.0 million senior unsecured term loan (the Term Loan), the proceeds of which will be used for working capital needs and for general corporate purposes. The Term Loan is due and payable on April 6, 2026. NW Holdings may prepay the Term Loan without premium or penalty (other than customary breakage costs, if applicable). Amounts prepaid may not be reborrowed.

The Term Loan Agreement bears interest at a per annum rate equal to the sum of (x) either (i) term SOFR with a one-, three- or six-month tenor, plus an adjustment of 0.10%, or (ii) the Alternate Base Rate, as defined in the Term Loan Agreement, plus (y)

the Applicable Margin, as defined in the Term Loan Agreement. The Applicable Margin is 0.90% per annum, for term SOFR loans, and 0.00% per annum, for Alternate Base Rate loans.

On March 12, 2025, NW Holdings entered into an Underwriting Agreement for the sale of $325.0 million in aggregate principal amount of the Company’s Junior Subordinated Debentures due September 15, 2055 (Junior Subordinated Debentures). The Company will pay interest on the Junior Subordinated Debentures (i) from and including the date of original issuance to, but not including, September 15, 2035, at an annual rate of 7.0% and (ii) from and including September 15, 2035, during each Interest Reset Period at an annual rate equal to the Five-Year Treasury Rate as of the most recent Reset Interest Determination Date plus 2.701%. The sale of the Junior Subordinated Debentures closed on March 18, 2025.

Interest Rate Swap Agreement

In January 2023, NWN Water entered into an interest rate swap agreement with a major financial institution for $55.0 million that effectively converted variable-rate debt to a fixed rate of 3.8%. Interest payments made between the effective date and expiration date are hedged by the swap agreement. The interest rate swap agreement expires in June 2026, along with the variable-rate debt.

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. These valuations are based on Level 2 inputs as defined in the fair value hierarchy. See Note 2 in the 2024 Form 10-K for a description of the fair value hierarchy.

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:

(1)Estimated fair value does not include unamortized debt issuance costs.

10. PENSION AND OTHER POSTRETIREMENT BENEFIT COSTS

NW Natural maintains a qualified non-contributory defined benefit pension plan (Pension Plan), 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.

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 (credit) for the pension and other postretirement benefit plans:

Net periodic benefit costs are reduced by amounts capitalized to NWN Gas Utility plant. In addition, net periodic benefit costs were recorded to a regulatory balancing account as approved by the OPUC and amortized accordingly.

The following table presents amounts recognized in accumulated other comprehensive loss (AOCL) and the changes in AOCL related to non-qualified employee benefit plans:

Employer Contributions to Company-Sponsored Defined Benefit Pension Plans

NW Natural made $2.6 million of cash contributions to its qualified defined benefit pension plans during the three months ended March 31, 2025 andno cash contributions during the three months ended March 31, 2024. During 2025, NW Natural expects to make additional cash contributions of approximately $8.7 million.

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 $4.0 million and $3.5 million for the three months ended March 31, 2025 and 2024, respectively.

See Note 10 in the 2024 Form 10-K for more information concerning these retirement and other postretirement benefit plans.

11. INCOME TAX

An estimate of annual income tax expense is made each interim period using estimates for annual pre-tax income, regulatory flow-through adjustments, tax credits, and other items. The estimated annual effective tax rate is applied to year-to-date, pre-tax income to determine income tax expense for the interim period consistent with the annual estimate. Discrete events are recorded in the interim period in which they occur or become known.

The effective income tax rate varied from the federal statutory rate due to the following:

The NW Holdings and NW Natural effective income tax rates for the three months ended March 31, 2025 compared to the same period in 2024 changed primarily as a result of the regulatory tax benefit amortization providing less rate benefit due to higher pre-tax income. See Note 11 in the 2024 Form 10-K for more detail on income taxes and effective tax rates.

The IRS Compliance Assurance Process (CAP) examination of the 2023 tax year was completed during the first quarter of 2025. There were no material changes to the return as filed. The 2024 and 2025 tax years are subject to examination under CAP.

12. PROPERTY, PLANT, AND EQUIPMENT

The following table sets forth the major classifications of property, plant, and equipment and accumulated depreciation:

13. INVESTMENTS

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

Investment in Life Insurance Policies

Other investments include financial investments in life insurance policies, which are accounted for at cash surrender value, net of policy loans. See Note 13 in the 2024 Form 10-K.

NW Natural Gas Reserves

NW Natural has invested $188 million through the gas reserves program in the Jonah Field located in Wyoming as of March 31, 2025. Gas reserves are stated at cost, net of regulatory amortization, with the associated deferred tax benefits of $2.6 million, $3.8 million, and $2.6 million, which are recorded as liabilities in the March 31, 2025, March 31, 2024, and December 31, 2024 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 $2.7 million, $2.2 million, and $2.7 million as of March 31, 2025, March 31, 2024, and December 31, 2024, respectively. See Note 13 in the 2024 Form 10-K.

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. NWN Water subsequently increased its ownership stake in Avion Water as follows:

Avion Water operates in Bend, Oregon and the surrounding communities, serving approximately 16,000 connections and employing 39 people. The carrying value of the equity method investment is $10.0 million higher than the underlying equity in the net assets of the investee at March 31, 2025 due to equity method goodwill. NWN Water's share in the earnings (loss) of Avion Water is included in other income (expense), net.

14. BUSINESS COMBINATIONS

2025 Business Combinations

On January 7, 2025 NW Holdings acquired 100% of the outstanding membership interests of SiEnergy Operating, LLC from SiEnergy Capital Partners, LLC, an affiliate of Ridgewood Infrastructure. Total consideration included $271.1 million in cash and the assumption of $156.1 million of outstanding debt. SiEnergy is a regulated natural gas distribution utility, serving approximately 73,000 customers in the greater metropolitan areas of Houston, Dallas, and Austin, Texas. SiEnergy also includes a regulated natural gas transmission utility serving customers in the greater metropolitan areas of Dallas and Austin, Texas.

The SiEnergy acquisition met the criteria of a business combination, and as such a preliminary 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 for net assets associated with SiEnergy. This allocation is considered preliminary as of March 31, 2025, as facts and circumstances that existed as of the acquisition date may be discovered as we continue to integrate SiEnergy. As a result, subsequent adjustments to the preliminary valuation of tangible assets, regulatory assets and liabilities including asset removal costs, contract assets and liabilities, tax positions, and goodwill may be required. Any such adjustments are to be completed within the one-year measurement period. Acquisition costs totaling $2.3 million in the fourth quarter of 2024 and $5.3 million in the first quarter of 2025 were expensed as incurred. Acquisition costs related to SiEnergy are included in operations and maintenance expenses in the consolidated statements of comprehensive income. The transaction aligns with NW Holdings' growth strategy and further expands the service territory in Texas.

Preliminary goodwill of $171.0 million was recognized from this acquisition. The goodwill recognized is attributable to SiEnergy's natural gas utility service territory, experienced workforce, and the strategic benefits 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 $178.6 million.

The following table summarizes the consideration transferred and the amounts of identified assets acquired and liabilities assumed as the acquisition date:

The table below presents the unaudited pro forma revenues and earnings of NW Holdings as if the acquisition had occurred as of January 1, 2024:

The unaudited pro forma results have been prepared for comparative purposes only and are not necessarily indicative of what would have occurred had the business combination been completed on January 1, 2024, nor is it necessarily indicative of future results of operations of the combined company. Pro forma net income for the three months ended March 31, 2024 and March 31, 2025 were adjusted to reflect the following:

•acquisition costs of $7.6 million incurred by NW Holdings' in the first quarter of 2025 and the fourth quarter of 2024, were reflected to have occurred in the first quarter 2024 and the first quarter 2025 costs were removed from the three months ended March 31, 2025 pro forma net income;

•the capital structure for NW Holdings' was modified to reflect the Junior Subordinated Debentures issued in March 2025 to represent the ongoing capital structure and reflects the issuance to have occurred on January first of each respective period;

•the results of SiEnergy were adjusted to represent results as though it were owned as of January first of each respective period; and

•all adjustments were net tax effected using a statutory tax rate of 26.5%

The amount of SiEnergy revenues and net income included in NW Holdings' consolidated statements of comprehensive income was $22.7 million and $5.5 million, respectively, for the three months ended March 31, 2025.

Other 2025 Business Combinations

During the first quarter of 2025, NWN Water and its subsidiaries acquired the assets oftwo additional businesses qualifying as business combinations. The aggregate fair value of the consideration transferred for these acquisitions was $1.6 million, most of which was allocated to property, plant and equipment. These transactions align with NW Holdings' water and wastewater sector strategy as it continues to expand its water and wastewater service territories and included:

•Everett Square, Inc. in Texas

•ES Water Utility Consolidators, Inc. in Texas

2024 Business Combinations

During the year ended December 31, 2024, NWN Water completed the acquisition of Infrastructure Capital Holdings (ICH), which includes 100% of the membership interests of the following entities:

•Avimor Water Reclamation Company, LLC

•Bents Court Water Company, LLC

•Emerald Valley Wastewater Company, LLC

•OMSID Infrastructure Holdings Company, LLC

•Quigley Recycled Water Company, LLC

•Mines Park Infrastructure Holdings Company, LLC

•Puttman Infrastructure Services Company, LLC

•Lakeshore Water Company, LLC

•Seavey Loop Water Company, LLC

•South Coast Water Company, LLC

The acquisition added wastewater and recycled water customers across Oregon, Idaho and California. The acquisition-date fair value of the total consideration transferred was $29.9 million.

The ICH acquisition met the criteria of a business combination, and as such a preliminary 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 for net assets associated with ICH. This allocation is considered preliminary as of March 31, 2025, as facts and circumstances that existed as of the acquisition date may be discovered as we continue to integrate ICH. As a result, subsequent adjustments to the preliminary valuation of tangible assets, contract assets and liabilities, tax positions, and goodwill may be required. Subsequent adjustments are not expected to be significant, and any such adjustments are expected to be completed within the one-year measurement period. The acquisition costs were not material and expensed as incurred.

Preliminary goodwill of $18.2 million was recognized from this acquisition. The goodwill recognized is attributable to ICH's 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 $18.4 million.

The following table summarizes the consideration transferred and the amounts of identified assets and liabilities assumed as the acquisition date:

The amount of ICH revenues and earnings included in NW Holdings' consolidated statements of comprehensive income is $1.3 million and $0.5 million, respectively, for the three months ended March 31, 2025.

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 $354.5 million, $163.0 million, and $183.8 million as of March 31, 2025, March 31, 2024, and December 31, 2024, respectively. Goodwill as of March 31, 2025 is attributable to gas utility, water and wastewater acquisitions, of which $171.0 million is included in the SiEnergy category and $183.5 million is included in the NWN Water category for segment reporting purposes. Goodwill as of March 31, 2024 and December 31, 2024 is only attributable to water and wastewater acquisitions and is included in the NWN Water 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 primarily to hedge a portion of the NWN Gas Utility 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 hedging interest rates and 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 NWN Gas Utility 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 vary between states due to different rate structures and hedging 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 fully recovered and reflected in the weighted-average cost of gas in the PGA filing. Hedge contracts entered into after the start of the PGA period for the current PGA year 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 Washington gas supplies.

NW Natural entered the 2024-25 gas year with forecasted sales volume hedged at approximately 80% in total, including 64% in financial hedges and 16% in physical gas supplies. The total hedged for Oregon was approximately 86%, including 69% in financial hedges and 17% in physical gas supplies. The total hedged for Washington was approximately 32%, including 19% in financial hedges and 13% in physical gas supplies.

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 NWN Gas Utility 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 net losses of $46.2 million and net losses of $50.5 million for the three months ended March 31, 2025 and 2024, respectively, from the settlement of natural gas financial derivative contracts. Realized gains and losses offset the higher or lower cost of gas purchased, resulting inno 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 March 31, 2025 or 2024. 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 based on our credit rating 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 2025 or 2024. 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 in NW Natural's ability to perform.

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 its counterparties, NW Natural's physical and financial derivative position would result in an asset of $2.6 million and a liability of $31.7 million as of March 31, 2025, an asset of $4.1 million and a liability of $61.4 million as of March 31, 2024, and an asset of $4.4 million and a liability of $86.0 million as of December 31, 2024.

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. See Note 15 in the 2024 Form 10-K for additional information.

Fair Value

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 adjustment for all financial derivatives outstanding to the fair value calculation was $0.1 million, which decreased the liability at March 31, 2025. The net fair value was a liability of $29.1 million, a liability of $57.3 million, and a liability of $81.6 million as of March 31, 2025 and 2024, and December 31, 2024, respectively. No Level 3 inputs were used in our derivative valuations during the three months ended March 31, 2025, and 2024. See Note 2 in the 2024 Form 10-K.

NWN Water Interest Rate Swap Agreement

In January 2023, NWN Water entered into an interest rate swap agreement with a major financial institution for $55.0 million that effectively converted variable-rate debt to a fixed rate of 3.8%. Interest payments made between the effective date and expiration date are hedged by the swap agreement. The interest rate swap agreement expires in June 2026, along with the variable-rate debt.

Unrealized gains (losses) related to the interest rate swap agreement are recorded in AOCI on the consolidated balance sheet and totaled $0.0 million, $0.5 million and $0.2 million, net of tax, as of March 31, 2025 and 2024 and December 31, 2024, respectively. Realized gains or losses occur as a result of monthly swap settlements. Gains of $0.1 million and $0.4 million were reclassified from AOCI to net income during the three months ended March 31, 2025 and 2024, respectively. The estimated amount of gains recorded in AOCI as of March 31, 2025 that are expected to be reclassified to net income within the next twelve months is $54 thousand.

16. COMMITMENTS AND CONTINGENCIES

NWN Renewables is an unregulated subsidiary of NW Holdings established to pursue investments in RNG activities. NWN Renewables, through its subsidiary Ohio Renewables, executed agreements with a subsidiary of EDL, a global producer of sustainable distributed energy, to secure RNG supply from two production facilities that are designed to convert landfill waste gases to RNG. This arrangement consists of a development agreement, an exclusive use agreement, a purchase agreement, and various guarantees.

Under the development agreement, the EDL subsidiary is responsible for the development and construction of the facilities. The first facility was completed and commenced delivery of RNG to Ohio Renewables in September 2024. Upon reaching this milestone, Ohio Renewables paid $26.0 million to the EDL subsidiary. The second facility was completed and commenced delivery of RNG to Ohio Renewables in December 2024 at which point Ohio Renewables made an additional payment of $25.4 million to the EDL subsidiary. The payments were recorded as long-term prepaid assets and will be amortized based on the volumes delivered over the life of the agreement.

NWN Renewables Purchase Agreements

Under the purchase agreement, Ohio Renewables and the subsidiary of EDL executed agreements for Ohio Renewables to purchase up to an annual specified amount of RNG produced by the EDL facilities over a 20-year period at a contractually specified price. We currently estimate the amount of RNG purchases from both facilities based on prices and quantities specified in the agreements to be as follows: approximately $18.9 million in 2025, $18.9 million in 2026, $22.8 million in 2027, $22.8 million in 2028, $24.1 million in 2029 and $532.6 million thereafter.

NW Holdings entered into a guarantee on behalf of Ohio Renewables with EDL. Per the guarantee, NW Holdings unconditionally and irrevocably guarantees the timely payment and performance when due of all obligations of Ohio Renewables. NW Holdings has not recognized a liability for its obligations under the guarantee in accordance with ASC 460, Guarantees.

NWN Renewables Sale Agreements

2024 - 2026

Ohio Renewables has contracted to sell RNG produced by the EDL facilities up to certain specified volumes in each of calendar years 2024 through 2026 to an investment-grade counterparty. Upon each delivery of RNG, Ohio Renewables will purchase an equal quantity of natural gas without renewable attributes at the same delivery point. Ohio Renewables has separately contracted to sell the natural gas purchased from EDL to another counterparty also at the same delivery point upon receipt. Alongside these agreements, NW Holdings entered into a guarantee on behalf of Ohio Renewables. Per the guarantee, NW Holdings unconditionally and irrevocably guarantees the prompt payment of all present and future obligations of Ohio Renewables. NW Holdings has not recognized a liability for its obligations under the guarantee in accordance with ASC 460, Guarantees.

The guarantee specifies annual cap amounts on the aggregate liability covered by the Guarantee as follows:

2025 - 2042

Ohio Renewables additionally has contracted to sell a fixed-volume amount of RNG under a long-term agreement with an investment-grade utility beginning in 2025 and extending through 2042. Under the current contract, if less than 75% of the contracted volumes of RNG are not delivered on an annual basis, Ohio Renewables is obligated to pay the per MMbtu price for volumes between the amount delivered and 75% of the contracted volumes on an annual basis. NW Holdings entered into a guarantee on behalf of Ohio Renewables. Per the guarantee, NW Holdings unconditionally and irrevocably guarantees the prompt payment of all present and future obligations of Ohio Renewables. The total liability under this guarantee cannot exceed $2.0 million. NW Holdings has not recognized a liability for its obligations under the guarantee in accordance with ASC 460, Guarantees.

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:

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 thanone 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 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 and the EE/CA estimated the 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 submitted a Preliminary Design Report, which EPA approved in December 2024. 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 $52.4 million to $350 million. NW Natural has recorded a liability of $52.4 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.

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 million in 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 intwo 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.

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.

In December 2024, NW Natural submitted the Gasco uplands FS to ODEQ. The FS presents a set of remedial action alternatives and provides the basis for range of potential remedial costs for the site. The estimated costs for the alternative remedies range from $43.8 million to $358 million. NW Natural has recorded a liability of $43.8 million, which reflects the low end of the range.

Additionally, the EPA's Gasco sediments Administrative Order requires the integration of upland source controls with the sediment remedy. The selected sediment remedy, which is discussed above under "Gasco Sediments," is currently under separate design for the EPA. To comply with the source control integration requirement, some Gasco uplands work must be expedited. An Interim Removal Action Measure (IRAM) for the Gasco uplands is the regulatory mechanism ODEQ has selected to accomplish that goal. As a result, the Gasco uplands FS also includes a separate cost range for the IRAM. The estimated costs for the IRAM range from $8.9 million to $78 million. NW Natural has recorded a liability of $8.9 million, which reflects the low end of the range.

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. Four years of post-construction monitoring have demonstrated that the cap is intact and the remedy is performing as designed. NW Natural has recognized an additional liability of $1.0 million associated with long-term monitoring 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. See Note 17 in the 2024 Form 10-K for a description of SRRM and ECRM collection processes.

The following table presents information regarding the total regulatory asset deferred:

(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 $33 thousand at March 31, 2025, $34 thousand at March 31, 2024, and $36 thousand at December 31, 2024.

(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 for 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 NWN Gas Utility rates, subject to an earnings test.

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.

Legal Proceedings

On October 11, 2024, NW Natural was added as a defendant to an ongoing lawsuit brought by Multnomah County in the Circuit Court for Multnomah Count, Oregon(County of Multnomah v. Exxon Mobil Corp., et. al., No.23-cv-25164) against more than a dozen oil and gas producers seeking damages relating to climate change impacts. The County asserts various causes of action, including negligence, fraud, trespass and public nuisance under Oregon law related to the refining, producing and/or marketing of fossil fuels. NW Natural is diligently defending against the claims.

On October 14, 2024, NW Natural and NW Holdings were named as the defendants in a lawsuit filed in the Circuit Court for Multnomah County, Oregon(Blumm et. al. v. Northwest Natural Gas Company, 24-cv-48490), that is seeking class certification on behalf of all Oregon NW Natural Smart Energy-enrolled customers during the past approximately six years. The lawsuit alleges claims under Oregon's Unlawful Trade Practices Act and for breach of contract, with respect to NW Natural's Smart Energy program. The plaintiffs seek injunctive and equitable relief and damages. We are diligently defending against the claims.

NW Natural and NW Holdings are 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

See Note 17 in the 2024 Form 10-K.

For additional information regarding other commitments and contingencies, see Note 16 in the 2024 Form 10-K.

18. SUBSEQUENT EVENT

Business Acquisition

In May 2025, SiEnergy's wholly-owned subsidiary, Si Investment Co, LLC (Si Investment Co) entered into an agreement to acquire Hughes Gas Resources, Inc. (Hughes) from EPCOR USA Inc. for $60 million (subject to customary purchase price adjustments). Hughes serves approximately 6,900 residential and commercial customers in the greater Houston metropolitan area. Upon closing the transaction, which is expected to occur in the second quarter of 2025, Hughes will become a wholly owned subsidiary of Si Investment Co. Hughes is regulated by the Railroad Commission of Texas. No regulatory approvals are needed to close this transaction. The transaction is subject to customary closing conditions.

ITEM 2. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS