PINNACLE WEST CAPITAL CORP

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

SCHEDULE 14A

PROXY STATEMENT PURSUANT TO SECTION 14(a)

OF THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. )

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PINNACLE WEST CAPITAL CORPORATION

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A Message from Our Chairman, President and CEO

Jeffrey B. Guldner

Chairman of the Board, President

and Chief Executive Officer

To our Shareholders:On behalf of our Board of Directors, management, and employees, I invite you to participate in our 2024 Annual Meeting of Shareholders. The meeting will be held at 1:30 p.m. (EDT), Wednesday, May 22, 2024. Details regarding how to attend the meeting and the business to be conducted are in the accompanying Notice of Annual Meeting and Proxy Statement.

2023 Highlights

Your Company had many success stories in 2023 and I am proud of our accomplishments. My letter in our Annual Report on Form 10-K for the fiscal year ended December 31, 2023 will provide you the details of some of our accomplishments, but a few that I would like to specifically mention here are:

•our outstanding operational performance, including the fact that Palo Verde Generating Station attained its 32nd consecutive year as the nation’s largest power producer, all of it carbon-free;

•the significant increase in customer satisfaction, including the improvement in our J.D. Power rankings in which APS ranked in the second quartile of large investor-owned utilities for both business and residential customers in 2023;

•the strengthening of our financials, including minimizing shareholder impact from the 2019 rate case decision by deferring any equity issuance, managing costs and capital allocation, and sustaining dividend growth; and

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•the outstanding performance by our employees. In the Summer of 2023, Arizona had a record 22 days of temperatures 115 degrees or higher and 55 days above 110 degrees. On July 15, 2023, customers shattered the all-time Company record with a peak demand of 8,162 MWs and exceeded the 2020 record of 7,660 MWs on 18 different days in July and August of 2023. All the while, our employees kept the power flowing and the lights on – consistently delivering on our promise of safely providing reliable service.

You should be proud of what your Company accomplished in 2023.

Rate Case Outcome

In 2022 and 2023, we progressed through a new rate case which overall culminated in a constructive outcome. You can read more about the rate case outcome in the Proxy Statement on page 5. The resulting outcome of this rate case will have multiple constructive impacts for the Company, including allowing us to continue to invest in the growth of the state, deliver affordable and reliable power to our customers, and improve shareholder value. However, we are still mindful that we continue to face challenges from lagging historical costs due to rising interest rates and inflationary pressures. We look forward to working with the Arizona Corporation Commission on addressing these lagging costs in the near future.

The APS Promise and the 10-Year Strategic Plan

The APS Promise sets forth our purpose, our vision and our mission:

•Purpose: As Arizona stewards, we do what is right for the people and prosperity of our state.

•Vision: Create a sustainable energy future for Arizona.

•Mission: Serve our customers with clean, reliable, and affordable energy.

You can read more about the APS Promise on the inside back cover of this Proxy Statement.

Our 10-Year Strategic Plan outlines how we will deliver on the APS Promise. You can read more about the Plan on page 64 of this Proxy Statement. In 2023, we continued our focus on categorizing our strategy and business planning ambitions into two different time horizons:

•Today-forward, where we focus on near-term execution to maximize the potential of our current business with metrics that focus on today and now. In our today-forward planning, we look at numerous factors, including our corporate and business unit plans, our tiered metrics, the Company’s position on key issues and topics, and our strategic initiatives.

•Future-back, where we look at how we change the business over the next decade in order to execute on our Vision and Mission. In our future-back planning, we focus on our long-term strategies and risks, we engage in future state scenario planning, and we scan the external environment for opportunities and risks related to our business model.

Your leadership team recognizes that Arizona is in the midst of a transformation. Our state’s population continues to grow, especially in Maricopa County, and Phoenix is booming as a vibrant commercial hub in the Southwest region, attracting an influx of new residents and businesses, with large industrial customers and data centers continuing to express interest in the Valley. At the same time, our customers’ needs and preferences are evolving, including increased demand for innovative demand-side programs and options to purchase clean energy directly. We continue to review, refine, and implement our strategic plan to meet the opportunities and challenges presented by the growth in our state and our customers’ choices, expectations, and satisfaction. We believe this strategic approach and focus will drive shareholder value.

Board of Directors

I want to thank the Board of Directors for their outstanding support in 2023. Our Board of Directors plays a vital role in establishing our corporate strategy. I can assure you that our Board is extremely thoughtful and engaged in our Company, our strategy, and our performance.

As we noted last year, Kathy Munro will be retiring from the Board at the Annual Meeting. I want to personally thank her for the guidance, knowledge, and expertise that she has brought to the Board and to the leadership team over the years. We are a stronger Company thanks to her service as a director.

Finally, your vote is important to us. Whether or not you plan to participate in the Annual Meeting, we encourage you to vote promptly. You may vote on the internet; by telephone; or by completing, signing, dating, and returning a Proxy Card or Voting Instruction Form.

Thank you for your investment and continued support of Pinnacle West.

Sincerely,

Jeffrey B. Guldner

Chairman of the Board, President

and Chief Executive Officer

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A Message from Our Independent Directors

Dear Fellow Shareholders,

As Independent Directors, we are committed to sound governance principles, and are focused on ensuring long term value for our shareholders as Pinnacle West makes progress toward our clean energy goals, while improving customer satisfaction, ensuring reliability and affordability. Below we highlight a few areas of focus for 2023.

Oversight of Strategy

The energy industry is rapidly changing, largely in part due to the development of new technologies, as well as an emphasis on clean energy by customers, investors, and other stakeholders. The energy landscape in Arizona is experiencing unprecedented load growth and increases in demand for energy. At our Board meetings and during our Strategic Retreat, we engaged with the management team in robust discussions about overall strategy, business priorities, long-term risks, and growth opportunities. The Today-Forward and Future-Back strategic framework allows the Board to actively monitor the changing landscape, while focusing on shareholder returns, customer experience and satisfaction, system reliability, resiliency, and affordability.

Risk and Risk Management

Risk, and risk management, are issues that the Board reviews on a regular basis. As you will note on page 39 of the Proxy Statement, the Board engages in detailed risk review discussions with the management team, as well as the employee subject matter experts when appropriate. In 2023, we also engaged in a thorough and comprehensive review of the risks identified in this Proxy Statement and other risks identified by the Company as its top risks. We understand that a critical role of the Board is risk oversight; be assured it is a priority for the Board and one that we actively address.

Improved Regulatory Outcome

In the last two years, one of the Company's strategic initiatives was to achieve more productive outcomes from the Arizona Corporation Commission by enhancing our engagement with commissioners and other stakeholders. This strategy was a thoughtful undertaking by the management team, fully supported by the Board. Management’s engagement strategy has resulted in a number of favorable decisions for APS in the last year and you can read more about these outcomes in Jeff's letter in the Annual Report. We will maintain our focus on this engagement strategy and support management's efforts to improve outcomes with the Arizona Corporation Commission so that we can invest in the infrastructure needed to support Arizona's growth while delivering reliable and affordable power and improving shareholder value.

Shareholder Outreach

What our investors think is very important to us. We support management’s efforts to engage with a broad set of stakeholders throughout the year, and the independent directors stand ready to engage with our investors as well. We appreciate your perspectives and we review your comments and feedback and incorporate them into our decision making.

Board Composition

Board composition is one of our most important responsibilities, and it is clear that our succession planning approach to Board membership is working successfully and as planned. In 2023, Dale Klein, former Chair of the Nuclear Regulatory Commission, retired from the Board. We retained the nuclear expertise with the addition of Kristine Svinicki, also a former Chair of the Nuclear Regulatory Commission. This is indicative of our approach to Board membership, showing that we are looking at, and planning for, the current and future areas of expertise that will be needed to best serve the Company and its shareholders.

We believe in the business value of having diverse perspectives in the boardroom. We are deliberate in ensuring we have the right mix of perspectives, skills, and expertise to address the Company’s current and future needs.

Sadly, we will be saying goodbye to Kathy Munro at the 2024 Annual Meeting of Shareholders. Kathy has been a leader, mentor, and phenomenal asset to Pinnacle West and its shareholders. We will miss her guidance and expertise. Paula Sims, a proven leader with utility experience, has taken on the role of Lead Director and Chairman of the Corporate Governance and Public Responsibility Committee. We made a few other important changes to our Board leadership structure in 2023. Bill Spence took over the role of Chairman of the Nuclear and Operating Committee, and Jim Trevathan is now Chairman of the Finance Committee. Both individuals bring experience, expertise, and new perspectives to their committees.

Thank you for the trust you place in us. The Board is engaged and committed to our common goal of creating enduring, long-term value for customers, employees, and shareholders alike.

Sincerely,

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