Centuri Holdings Inc

Amended Form of Long-term Incentive Cash Award Agreement

On February 25, 2025, the Compensation Committee of the Board of Directors approved a new form of long-term incentive cash award agreement (“LTIP Agreement”), which will be used to make long-term incentive cash awards to members of the Company’s senior management team, including the Company’s named executive officers.

Subject to the provisions of the LTIP Agreement, the Compensation Committee may determine the payment amount or range of payment amounts for any cash-based award and the terms of any such award, including, without limitation, the length of the performance period, any performance goals to be achieved during any performance period, the extent to which an award may be subject to reduction, cancellation, forfeiture or recoupment. In addition, the new LTIP Agreement also eliminates restrictive covenants (confidentiality, non-solicitation and noncompetition provisions) as a precondition for receiving awards under the agreement as such restrictive covenants already exist in the employment agreements that award recipients have signed.

The above description of the LTIP Agreement is qualified in its entirety by reference to the full text of the form of LTIP Agreement, which is filed as Exhibit 10.23 hereto and incorporated herein by reference.

Unutilized Tax Assets Agreement with Southwest Gas Holdings

On February 24, 2025, we entered into an Unutilized Tax Assets Settlement Agreement (the “Tax Assets Agreement”) with Southwest Gas Holdings. The Tax Assets Agreement addresses our arrangements with Southwest Gas Holdings with respect to certain unutilized tax assets (the “Tax Assets”) that we will retain following any deconsolidation from Southwest Gas Holdings 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 made by Southwest Gas Holdings in respect of the Tax Assets will be treated as deemed capital contributions, which will result in an increase in Southwest Gas Holdings’ basis in its ownership of our common stock. The deemed capital contributions will not require any cash payment from the Company and will have no impact on our liquidity or financial condition. Deconsolidation for federal income tax purposes occurs at the time when Southwest Gas no longer owns at least 80% of our 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 10.17 hereto and incorporated herein by reference.

Rule 10b5-1 Trading Arrangements

During the fiscal three months ended December 29, 2024, none of our directors or officers (as defined in Rule 16a1(f) under the Exchange Act)adopted orterminated any contract, instruction, or written plan for the purchase or sale of the Company’s securities intended to satisfy the conditions of the affirmative defense provided by Rule 10b5-1(c) or any “Rule 10b5-1 trading arrangement” (as defined in Item 408 of Regulation S-K).