Southwest Gas Holdings Inc

During the fiscal quarter ended December 31, 2024, none of our directors or officers (as defined in Rule 16a-1(f) of the Exchange Act)adopted, modified, orterminated a “Rule 10b5-1 trading arrangement” or “non-Rule 10b5-1 trading arrangement,” as those terms are defined under Item 408 of Regulation S-K.

Tax Assets Agreement with Centuri

On February 24, 2025, we entered into a Tax Assets Agreement with Centuri and its wholly owned subsidiary, Centuri Group, Inc. (collectively, the “Centuri Parties”). The Tax Assets Agreement addresses our arrangements with the Centuri Parties with respect to certain unutilized tax assets (the “Tax Assets”) that the Centuri Parties will retain following any deconsolidation from us for U.S. federal and relevant state income tax laws. Under the terms of the Tax Assets Agreement, the balance of the Tax Assets at tax deconsolidation, subject to true-up and including the impact of any payments or deemed payments that we make in respect of the Tax Assets, will be treated as deemed capital contributions, which will result in an increase in the tax basis of our ownership of our Centuri common stock. Deconsolidation for federal income tax purposes occurs at the time when we no longer own at least 80% of the outstanding Centuri common stock, and the deconsolidation for state law purposes occurs at various points depending on the relevant tax law of each state.

The foregoing description of the Tax Assets Agreement is qualified in its entirety by the full text of the Tax Assets Agreement, which is filed as exhibit 10.56 to this Annual Report on Form 10-K.