NORTHWEST NATURAL GAS CO

LC Reimbursement Facility

The following disclosure is intended to satisfy any obligation to provide disclosures pursuant to Item 1.01 and 2.03 of Form 8-K.

On May 1, 2026, NW Natural entered into a Reimbursement Agreement and Continuing Indemnity Relating to Standby Letters of Credit/Letters of Guarantee (LC Reimbursement Agreement), between NW Natural and The Toronto-Dominion Bank, New York Branch (TD Bank), pursuant to which NW Natural agreed to reimburse TD Bank for disbursements in respect of letters of credit issued pursuant to the LC Reimbursement Agreement from time to time.

NW Natural expects to use the letters of credit issued under the facility created by the LC Reimbursement Agreement (the LC Facility) primarily to support its participation in Washington Climate Commitment Act cap-and-invest program auctions.

The 2026 LC Reimbursement Agreement provides that the aggregate undrawn face amount of letters of credit issued thereunder may not exceed $100 million.

Drawings under letters of credit issued under the LC Facility are required to be reimbursed by NW Natural on the date that NW Natural is notified thereof or, in certain cases, on the next business day. If NW Natural does not reimburse a drawing when due, its reimbursement obligation accrues interest at Standard Overnight Financing Rate plus 2.00% per annum.

TD Bank has no commitment to issue letters of credit under the LC Facility and has the discretion to limit and condition the terms for the issuance of letters of credit (including maximum face amounts) in its sole discretion. The LC Reimbursement Agreement does not have a specified term. NW Natural or TD Bank may terminate the LC Facility at any time in their sole discretion.

Obligations of NW Natural under the LC Reimbursement Agreement are unsecured and rank pari passu with NW Natural’s other senior unsecured indebtedness, although NW Natural (a) granted to the agent or lenders party to the LC Reimbursement Agreement and certain of their affiliates certain setoff rights and (b) agreed to provide cash collateral (with respect to which NW Natural grants a security interest) after the occurrence of an event of default, in each case, as described further in the LC Reimbursement Agreement.

The LC Reimbursement Agreement is cross-defaulted to NW Natural's Amended and Restated Credit Agreement, dated as of November 3, 2025, among NW Natural, the lenders party thereto and JPMorgan Chase Bank, N.A., as administrative agent. The occurrence of these or any other Event of Default (as defined in the LC Reimbursement Agreement) would entitle TD Bank to require cash collateral for the Obligations, as defined in the LC Reimbursement Agreement, and to exercise all other rights and remedies available under the applicable LC Reimbursement Agreement and under applicable law.

The foregoing description of the LC Facility does not purport to be complete and is qualified in its entirety by reference to the LC Reimbursement Agreement, a copy of which is attached as Exhibit 10.1 to this Quarterly Report on Form 10-Q and is incorporated herein by reference.

Rule 10b5-1 Trading Arrangements

From time to time, our officers (as defined in Rule 16a-1(f) of the Exchange Act) and directors may enter into Rule 10b5-1 or non-Rule 10b5-1 trading arrangements (as each such term is defined in Item 408 of Regulation S-K).

On March 27, 2026, David H. Anderson, Director of NW Holdings and NW Natural, adopted a Rule 10b5‑1 trading arrangement for the sale of shares of NW Holdings’ common stock, which is intended to satisfy the affirmative defense conditions of Rule 10b5‑1(c) under the Exchange Act. Mr. Anderson’s Rule 10b5‑1 trading arrangement provides for the potential sale of up to 33,000 shares of NW Holdings’ common stock between June 26, 2026 and June 17, 2027, subject to conditions set forth in the arrangement, and so long as the market price of NW Holdings’ common stock is higher than certain minimum threshold prices specified in Mr. Anderson’s Rule 10b5‑1 trading arrangement.

As previously disclosed, Mr. Anderson retired as CEO of NW Holdings and NW Natural, effective April 1, 2025. Mr. Anderson currently holds over seven times the $450,000 stock ownership requirement for non‑management directors. This trading arrangement allows Mr. Anderson to periodically sell a portion of his NW Holdings common stock to diversify his holdings in connection with his retirement as CEO.

Except as described above, during the three months ended March 31, 2026, none of our other officers or directors adopted or terminated any such trading arrangements.