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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A Message from Our Chairman, President and CEO

A Message to Our Shareholders:On behalf of our Board of Directors, management, and employees, I invite you to participate in our 2026 Annual Meeting of Shareholders. The meeting will be held at 1:30 p.m. (EDT), Thursday, May 14, 2026. Details regarding how to attend the meeting and the business to be conducted are in the accompanying Notice of Annual Meeting and Proxy Statement.

In my first year as CEO of Pinnacle West and APS, we made solid progress on our strategic priorities: expand the grid while delivering safe, reliable and affordable service to existing customers, improve timely recovery of our grid investments, and a relentless focus on talent development. We also took significant steps in securing resources to continue powering Arizona’s unprecedented economic growth and prosperity for the long term.

2025 Highlights

Many of the Company’s 2025 accomplishments are featured in this year’s Annual Report Letter to Shareholders and this Proxy Statement, but I want to highlight a few that make our team and me especially proud:

Financial

•The Pinnacle West Board of Directors increased our shareholder dividend for the 14th consecutive year, demonstrating its continued commitment to shareholder return.

•Pinnacle West achieved year-end earnings of $5.05 per diluted share of common stock, above our initial expectations at the start of the year.

•We executed our largest annual capital plan in APS's history and plan to invest more than $2.5 billion annually through 2028 to support reliability and continued growth in our service territory.

Operations

•We negotiated an agreement to serve as anchor shipper for Transwestern Pipeline’s Desert Southwest natural gas pipeline expansion project.

•APS announced adding up to 2,000 MW natural gas generation to support reliability for existing customers and service requests from new extra-large commercial customers.

•We served customers with top-tier reliability during Arizona’s third-hottest summer on record as our system set three new peak demand records.

•Palo Verde operated at 100% summertime capacity.

People

•The Phoenix Business Journal ranked APS No. 1 in corporate philanthropy, and a record-high 41% of our employees volunteered their time in 2025, demonstrating that community service is embedded in our culture.

•US News and World Report named APS one of the Best Companies to Work for in Energy and Resources.

•We introduced new Talent Philosophy and Leadership Model frameworks to create a common language, clarity, and consistency for leadership and talent development.

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Customers And Communities

•APS ranked in the first quartile nationally for the J.D. Power Business Customer Satisfaction Study and the J.D. Power Utility Digital Experience Study.

•We also ranked in the first quartile nationally for residential customer overall satisfaction in the Escalent Cogent Syndicated Study.

•We supported customers in need with a variety of assistance resources. More than 85,000 limited-income customers received bill discounts totaling $56.2 million through the APS Energy Support program. In addition, 21,000 customers received $12.8 million in bill assistance from federal and state programs, the APS Crisis Bill Assistance program, and other sources.

You can be proud of what your Company accomplished.

Our Path Forward

We are navigating a period of extraordinary growth and rising energy demand, driven by Arizona’s expanding population, economic diversification, and the rapid emergence of high load factor customers including advanced manufacturing and data centers. Our strategic priorities are supported by delivering safe, reliable, and affordable energy, earning and keeping the trust of our customers, and ensuring the long-term strength and resilience of our company.

The 2025 Rate Case is central to our strategy, addressing the financial pressures from inflation, high interest rates, and regulatory lag that have eroded our earned returns—even as our customer base and sales grow. We are proposing a formula rate to support more gradual, predictable rate changes and timely cost recovery, to help improve financial stability and secure low-cost capital for critical investments. This updated rate design helps ensure that customers driving new infrastructure needs, especially large commercial and industrial users, are directly assigned the costs, protecting residential and smaller customers from cost shifts—growth pays for growth.

Success also depends on our employees. We are investing in talent development, succession planning, and new capabilities such as AI integration to ensure we remain a top employer in Arizona and build our future leadership pipeline.

By executing this strategy, Pinnacle West and APS will continue to power opportunity for Arizona, maintain top-quartile reliability, and deliver strong value to our shareholders. We are committed to comprehensive planning and responsible investment, ensuring our grid remains resilient and service remains affordable as we meet the challenges and opportunities ahead.

Board of Director Acknowledgment

I want to thank the Board of Directors for their exceptional support in 2025. Our Board plays a vital role in developing our corporate strategy. Each member brings considerable expertise and a strong commitment to our Company’s success. I truly value their insight and engagement and look forward to partnering with them as we shape the future of Pinnacle West and APS.

I especially want to recognize Rick Fox, who will retire from the Board this year. We will miss his deep insights into many different corporate disciplines and engagement with our leadership team. We thank him for his 12 years of service to the Company.

Thank You to Our Investors

Finally, your vote is important to us. Whether or not you plan to participate in the Annual Meeting of Shareholders, 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.

We thank you for your investment and continued support of Pinnacle West.

Sincerely,

Theodore N. Geisler

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. We are concentrating on balancing the unprecedented growth forecast while delivering reliability at an affordable price, as well as managing risk and succession in a dynamic industry. We are honored to serve as your Board of Directors. Below are a few highlights of our activities during 2025:

CEO Transition

Effective April 1, 2025, we appointed Ted Geisler as Chairman of the Board, President and Chief Executive Officer of Pinnacle West and APS. Ted’s previous roles as President, CFO, years in operations and strategy and his deep knowledge of the Arizona business climate, prepared him well and allowed for a smooth transition. He and the Board are focused on building a resilient, high performing team with long-term capabilities by advancing the Company's talent strategy.

Strategic Plan Oversight

At our Board meetings and during our Strategic Retreat, we engage with the management team in robust discussions about overall strategy, business priorities, long-term risks, and growth opportunities while focusing on shareholder returns, customer experience and satisfaction, system reliability, resiliency, and affordability.

Constructive Regulatory Environment

Also in 2025, APS filed its rate case with the Arizona Corporation Commission designed to modernize its regulatory framework, mitigate cost recovery lag, and create predictability for customers and investors. The Company has remained focused on maintaining a constructive relationship with the Arizona Corporation Commission by continuing our engagement with commissioners and other stakeholders. As we move into 2026 and the rate case hearings, the Board will remain focused on constructive regulatory outcomes that support the Company’s continued investment in the infrastructure required for Arizona's growth, while ensuring delivery of safe, reliable and affordable power and generating competitive shareholder returns.

Risk, Risk Management, and Artificial Intelligence

Risk, and risk management, are issues that the Board reviews on a regular basis. As you will note on page 17 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 2025, we also engaged in a thorough and comprehensive review of the risks identified in this Proxy Statement and other risks identified by the Company, noting in particular, that wildfire, cybersecurity, resource adequacy risks, customer rates, and data center demand have been, and will continue to be, areas of focus for the Board. The Board also received periodic updates on artificial intelligence as it relates to, among other things, business strategy and potential uses, risks and mitigation and governance. 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.

Long-Term Financial Health

APS is experiencing historic growth across its service territory. The Company's long-term financial plan is focused on investing in grid infrastructure to secure a reliable grid while meeting the demands of APS's growing service territory. The Board is steadfast in supporting a long‑term financial plan that maintains strong credit metrics, aligns disciplined capital allocation with a reliable and affordable energy system, and holds management accountable for prudent cost management while achieving competitive long-term shareholder returns.

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Board Succession

This year we will say goodbye to Rick Fox, a long-standing and extremely valued member of the Board. Among other things, Rick has served as Chairman of the Human Resources Committee and is currently a member of the Audit Committee, Corporate Governance and Nominating Committee, and Human Resources Committee. Rick's leadership, guidance, and expertise have been beneficial during our Board refreshment process.

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 lead director has had the opportunity 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.

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

Sincerely,

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Notice of the 2026 Annual Meeting of Shareholders

VOTING ITEMS

1.To elect ten Directors to serve until the 2027 Annual Meeting of Shareholders

FOR each Director nominee

2.To hold an advisory vote to approve executive compensation

FOR

3.To ratify the appointment of our independent registered public accounting firm for the year ending December 31, 2026

FOR

Your vote is important. Whether you plan to participate in the Annual Meeting or not, please promptly vote by telephone, the internet, Proxy Card, or Voting Instruction Form.By order of the Board of Directors,Shirley BaumCorporate SecretaryApril 3, 2026The Proxy Statement and form of proxy are first being made available to shareholders on or about April 3, 2026.

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