8-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

| Date of report (Date of earliest event reported): | December 11, 2024 | | --- | --- || Commission File<br>Number | Exact Name of Each Registrant as specified in its<br>charter; State of Incorporation; Address; and<br>Telephone Number | | | IRS Employer<br>Identification No. | | --- | --- | --- | --- | --- | | 1-8962 | PINNACLE WEST CAPITAL CORPORATION | | | 86-0512431 | | | (an Arizona corporation) | | | | | | 400 North Fifth Street, P.O. Box 53999 | | | | | | Phoenix | Arizona | 85072-3999 | | | | (602) | 250-1000 | | | | 1-4473 | ARIZONA PUBLIC SERVICE COMPANY | | | 86-0011170 | | | (an Arizona corporation) | | | | | | 400 North Fifth Street, P.O. Box 53999 | | | | | | Phoenix | Arizona | 85072-3999 | | | | (602) | 250-1000 | | |

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (17 CFR §230.405) or Rule 12b-2 of the Securities Exchange Act of 1934 (17 CFR §240.12b-2).

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ¨

This combined Form 8-K is separately filed or furnished by Pinnacle West Capital Corporation and Arizona Public Service Company. Each registrant is filing or furnishing on its own behalf all of the information contained in this Form 8-K that relates to such registrant and, where required, its subsidiaries. Except as stated in the preceding sentence, neither registrant is filing or furnishing any information that does not relate to such registrant, and therefore makes no representation as to any such information.

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

(b) Retirement of Jeffrey B. Guldner as Chairman of the Board of Directors, Chief Executive Officer and President

On December 12, 2024, Pinnacle West Capital Corporation (“Pinnacle West”) and Arizona Public Service Company (“APS”) announced that Jeffrey B. Guldner will retire from his positions as Chairman of the Board, President, Chief Executive Officer and member of the Board of Directors of Pinnacle West and as Chairman of the Board, Chief Executive Officer and member of the Board of Directors of APS, effective April 1, 2025. Mr. Guldner will remain an employee of Pinnacle West as a non-officer special advisor to the Chief Executive Officer until March 31, 2026 in order to support a smooth transition. In connection with this change, Mr. Guldner’s annual base salary will be reduced to $600,000 beginning on April 1, 2025. Mr. Guldner’s incentive opportunity under the APS 2025 Annual Incentive Award Plan is discussed in a separate Current Report on Form 8-K, which is expected to be filed on December 12, 2024.

(c) Appointment of Theodore N. Geisler as Chairman of the Board of Directors, Chief Executive Officer and President

On December 11, 2024, the Board of Directors of Pinnacle West appointed Theodore N. Geisler (age 46) to replace Mr. Guldner as Chairman of the Board, President, and Chief Executive Officer of Pinnacle West effective April 1, 2025, and the Board of Directors of APS appointed Mr. Geisler to replace Mr. Guldner as Chairman of the Board and Chief Executive Officer of APS effective April 1, 2025. Mr. Geisler was appointed President of APS in May of 2022 and he will continue to serve in this role. Mr. Geisler served as Senior Vice President and Chief Financial Officer of Pinnacle West and APS from January of 2020 to May of 2022. Mr. Geisler served as Vice President and Chief Information Officer of APS from May of 2018 to January of 2020.

In connection with these appointments, Mr. Geisler’s annual base salary will increase to $1,000,000 on April 1, 2025, contingent upon him taking over the roles of Chairman of the Board, President and Chief Executive Officer of Pinnacle West and Chairman of the Board and Chief Executive Officer of APS on April 1, 2025. Mr. Geisler will also receive a long-term incentive grant award on April 1, 2025 in the amount of $3,000,000, in the form of a combination of performance share awards and restricted stock unit awards, also contingent upon him assuming the roles identified above.

Mr. Geisler’s incentive opportunity under the APS 2025 Annual Incentive Award Plan is discussed in a separate Current Report on Form 8-K, which is expected to be filed on December 12, 2024.

(d) Appointment of a New Director

The Board of Directors of Pinnacle West appointed Theodore N. Geisler to the Pinnacle West Board of Directors effective December 11, 2024. Mr. Geisler was also appointed to the APS Board of Directors, effective December 11, 2024. Mr. Geisler receives no additional compensation in connection with these appointments.

Item 7.01 Regulation FD Disclosure

A copy of the press release announcing these changes has been furnished as Exhibit 99.1 to this current report.

Item 9.01    Financial Statements and Exhibits.

(d)    Exhibits

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, each registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Document

Exhibit 99.1

PINNACLE WEST AND APS ANNOUNCE LEADERSHIP SUCCESSION

PHOENIX – Pinnacle West Capital Corp. (NYSE: PNW) announced today that Pinnacle West and Arizona Public Service (APS) Chairman and CEO Jeff Guldner will retire as Chairman of the Board, CEO and board member on March 31, 2025, after 5 years of leading the company. APS President Ted Geisler will assume the roles of Chairman of the Board, President and Chief Executive Officer of Pinnacle West and APS effective April 1, 2025. Guldner will remain employed by Pinnacle West in a non-executive advisory capacity to support a smooth transition through the end of March 2026.

“We’re incredibly grateful for Jeff’s leadership since joining APS in 2004 as Director of Federal Regulatory Affairs and Compliance through his tenure as CEO,” said Pinnacle West Lead Director Paula Sims. “He cast a strong vision for a carbon-free future, and he initiated efforts to improve our customers’ experience and the long-term financial health of the company - the impacts of which can’t be overstated. Jeff’s passion for APS’s people, customers and the community has left an indelible mark.

“Following a thoughtful succession planning process, we are excited to announce Ted Geisler as our next Chairman and CEO,” Sims continued. “Ted brings a unique blend of operational and financial acumen and results-oriented leadership from his breadth of experience across our business. He is well-positioned to build on his success as President of APS, where he drove top-quartile rankings in reliability and customer satisfaction, achieved key regulatory outcomes and set the strategy that’s enabled us to expand and strengthen the grid.”

“Over my tenure as CEO, Ted has been a trusted partner and deeply involved in crafting and executing the company’s long-term strategy,” Guldner said of his successor. “No one understands our priorities better, and I have full faith Ted and the team will lead APS and Arizona successfully through the new era of growth that’s upon us.”

Geisler has been President of APS since 2022 and has held a series of leadership positions at the company during his 23-year career at APS.

“It’s an honor to continue to serve in this new capacity,” Geisler said. “I do so with deep respect and appreciation for Jeff, and for our essential role in powering Arizona’s progress. We have a

talented team and a strategy that has reliably delivered outstanding results for our customers, communities and shareholders. I look forward to continuing to work closely with Jeff during the transition and building on the plans in place that have set the stage for APS’s success.”

About Ted Geisler

Geisler began his career at APS in 2001 and has held positions on the executive team since 2018, including the past two years as President. His leadership journey includes critical roles such as Chief Financial Officer, Chief Information Officer, General Manager of Transmission and Distribution Operations and Director of Corporate Strategy, as well as other key positions across operations and corporate resources.

A third-generation Arizonan, Geisler is deeply committed to the community and is currently Chairman of the Board of the Arizona Chamber of Commerce and on the board of the Greater Phoenix Economic Council (GPEC). He sits on the W.P. Carey Dean’s Council at Arizona State University and recently was chosen as the 56th Fighter Wing Command Honorary Commander at Luke Air Force Base. He has previously served on the boards of Chicanos por la Causa and Boys and Girls Club of the Valley.

Geisler earned a Bachelor of Science degree from Colorado State University and an MBA from Arizona State University. He is a graduate of the Nuclear Reactor Technology Course at the Massachusetts Institute of Technology and the Strategic Financial Leadership Program at Stanford University’s Graduate School of Business.

About Pinnacle West Capital Corp.

Pinnacle West Capital Corp., an energy holding company based in Phoenix, has consolidated assets of more than $26 billion, about 6,500 megawatts of generating capacity and approximately 6,100 employees in Arizona and New Mexico. Through its principal subsidiary, Arizona Public Service, the company provides retail electricity service to about 1.4 million Arizona homes and businesses. For more information about Pinnacle West, visit the company’s website at pinnaclewest.com.