PINNACLE WEST ANNUAL SHAREHOLDER MEETING AND VOTING SUMMARY

The Company's 2024 Annual Meeting of Shareholders ("Annual Meeting") will be held at 1:30 p.m. Eastern Daylight Time (10:30 a.m., Arizona time), on Wednesday, May 22, 2024. The Annual Meeting will not be held at a physical location, but instead will be held virtually, where shareholders will participate by accessing a website using the internet. The Annual Meeting can be accessed at www.virtualshareholdermeeting.com/PNW. All shareholders of record at the close of business on March 14, 2024, are entitled to notice of and to vote at the Annual Meeting. To participate in the Annual Meeting, you will need the 16-digit control number included on the proxy card, the Internet Notice or the voting instruction form. You also will be able to vote your shares electronically during the Annual Meeting (other than shares held through our 401(k) Plan, which must be voted prior to the meeting).

Voting Instructions:
Vote prior to the Annual Meeting by internet

The website address for internet voting is on the Proxy Card, the Internet Notice, and the Voting Instruction Form. Internet voting is available 24 hours a day. 

Vote prior to the Annual Meeting by telephone

The toll-free number for telephone voting is on the Proxy Card, the Internet Notice, and the Voting Instruction Form. Telephone voting is available 24 hours a day.

Vote prior to the Annual Meeting by scanning the QR code

The QR code is on the Proxy Card, the Internet Notice, and the Voting Instruction Form, and is available 24 hours a day.

Vote prior to the Annual Meeting by mail

You may vote by mail by promptly marking, signing, dating, and mailing your Proxy Card or Voting Instruction Form (a postage-paid envelope is provided for mailing in the United States).

Vote during the Annual Meeting over the internet

To participate in the Annual Meeting, you will need the 16-digit control number included on the Proxy Card, the Internet Notice, or the Voting Instruction Form.

Shares held in your name or shares for which you are the beneficial owner but not the shareholder of record may be voted electronically during the formal business portion of the Annual Meeting. Shares held in the Pinnacle West 401(k) Plan cannot be voted during the Annual Meeting. If you hold shares in the Pinnacle West Investor Advantage Plan or brokerage account, and you plan to vote prior to the Annual Meeting by internet, telephone, or by scanning the QR code, you will need to submit your vote no later than 11:59 p.m. EDT on May 21, 2024. If you hold shares in the Pinnacle West 401(k) Plan, you will need to submit your vote to the plan trustee no later than 11:59 p.m. EDT on May 19, 2024 to vote your shares.

You may change your vote by: re-voting by telephone; re-voting by internet; or re-voting during the formal business portion of the Annual Meeting. For shares held in your name, you may change your vote by re-submitting a signed Proxy Card. In addition, for shares held in your name, you may also revoke a previously submitted Proxy Card by mailing to our Corporate Secretary a written notice of revocation. For shares for which you are the beneficial owner but not the shareholder of record, you may change your vote by re-submitting a signed Voting Instruction Form to your broker. In addition, for shares for which you are the beneficial owner but not the shareholder of record, you should contact your broker if you would like to revoke your vote.

Your vote is confidential. Only the following persons have access to your vote: election inspectors; individuals who help with the processing and counting of votes; and persons who need access for legal reasons. All votes will be counted by an independent inspector of elections appointed for the Annual Meeting.