UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of
the Securities Exchange Act of 1934 (Amendment No.     )

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Filed by a Party other than the Registrant  o
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o	Preliminary Proxy Statement
o	Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))
o	Definitive Proxy Statement
x	Definitive Additional Materials
o	Soliciting Material under §240.14a-12
Pinnacle West Capital Corporation
(Name of Registrant as Specified In Its Charter)
(Name of Person(s) Filing Proxy Statement, if other than the Registrant)
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C 1234567890 000004 ENDORSEMENT_LINE______________ SACKPACK_____________ MR A SAMPLE DESIGNATION (IF ANY) ADD 1 ADD 2 ADD 3 ADD 4 ADD 5 ADD 6 Vote by Internet • Go to www.envisionreports.com/PNW • Or scan the QR code with your smartphone • Follow the steps outlined on the secure website Important Notice Regarding the Availability of Proxy Materials for the Pinnacle West Capital Corporation Shareholder Meeting to be Held on May 18, 2016 Under Securities and Exchange Commission rules, you are receiving this notice that the proxy materials for the Annual Meeting of Shareholders are available on the Internet. Follow the instructions below to view the materials and vote online or request a copy. The items to be voted on and location of the Annual Meeting are on the reverse side. Your vote is important! This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. We encourage you to access and review all of the important information contained in the proxy materials before voting. The Company’s 2016 Proxy Statement and Annual Report and Form 10-K for the year ended December 31, 2015 are available at: www.envisionreports.com/PNW Easy Online Access — A Convenient Way to View Proxy Materials and Vote When you go online to view materials, you can also vote your shares. Step 1: Go to www.envisionreports.com/PNW to view the materials. Step 2: Click on Cast Your Vote or Request Materials. Step 3: Follow the instructions on the screen to log in. Step 4: Make your selection as instructed on each screen to select delivery preferences and vote. Q When you go online, you can also help the environment by consenting to receive electronic delivery of future materials. Obtaining a Copy of the Proxy Materials – If you want to receive a copy of these documents, you must request one. There is no charge to you for requesting a copy. Please make your request for a copy as instructed on the reverse side on or before May 4, 2016 to facilitate timely delivery. + C O Y 029E8F Shareholder Meeting Notice1234 5678 9012 345 IMPORTANT ANNUAL MEETING INFORMATION

. Pinnacle West Capital Corporation’s 2016 Annual Meeting of Shareholders will be held on May 18, 2016, 10:30 a.m. Mountain Standard Time, at the Heard Museum, 2301 North Central Avenue, Phoenix, Arizona 85004. Please see the 2016 Proxy Statement for additional information on how to obtain an admission card in order to attend the Annual Meeting. Proposals to be voted on at the meeting are listed below along with the Board of Directors’ recommendations. The Board recommends a vote FOR all nominees, FOR Proposals 2 and 3, and AGAINST Proposal 4. 1. Election of Directors: 01 - Donald E. Brandt, 02 - Denis A. Cortese, M.D., 03 - Richard P. Fox, 04 - Michael L. Gallagher, 05 - Roy A. Herberger, Jr., Ph.D., 06 - Dale E. Klein, Ph.D., 07 - Humberto S. Lopez, 08 - Kathryn L. Munro, 09 - Bruce J. Nordstrom, 10 - David P. Wagener; Vote on an advisory resolution to approve executive compensation as disclosed in the 2016 Proxy Statement; Ratify the appointment of the Company’s independent accountants for the year ending December 31, 2016; Vote on the approval of a shareholder proposal regarding a report on political spending, if properly presented at the meeting. 2. 3. 4. PLEASE NOTE – YOU CANNOT VOTE BY RETURNING THIS NOTICE. To vote your shares you must vote online or request a paper copy of the proxy materials to receive a proxy card. Here’s how to order a copy of the proxy materials and select a future delivery preference: Paper copies: Current and future paper delivery requests can be submitted via the telephone, Internet or e-mail options below. E-mail copies: Current and future e-mail delivery requests must be submitted via the Internet following the instructions below. If you request an e-mail copy of current materials you will receive an e-mail with a link to the materials. PLEASE NOTE: You must use the number in the shaded bar on the reverse side when requesting a set of proxy materials. g Internet – Go to www.envisionreports.com/PNW and click Cast Your Vote or Request Materials. Follow the instructions to log in and order a copy of the current meeting materials and submit your preference for e-mail or paper delivery of future meeting materials. Telephone – Call us free of charge at 1-866-641-4276 and follow the instructions to log in and order a paper copy of the materials by mail for the current meeting. You can also submit a preference to receive a paper copy for future meetings. E-mail – Send e-mail to investorvote@computershare.com with “Proxy Materials Pinnacle West Capital Corporation” in the subject line. Include in the message your full name and address, plus the number located in the shaded bar on the reverse, and state in the e-mail that you want a paper copy of current meeting materials. You can also state your preference to receive a paper copy for future meetings. To facilitate timely delivery, all requests for a paper copy of the proxy materials must be received by May 4, 2016. g g 029E8F Shareholder Meeting Notice