Important Information Regarding the Pinnacle West Investors Advantage Plan

Automatic Investment Option – Deductions will occur on the 25^th calendar day for the month, or the previous business day if the 25^th falls on a holiday or weekend.

Cash Investments – Cash Investments may be made by check, payable through a U.S. bank or other Financial institution, in U.S. dollars, to Computershare. Generally, the funds will be invested on Thursday of each week. If the investment date falls on ex dividend date, the investment funds will not receive the dividend.

Initial Cash Investment – The minimum initial investment is $50, and there is no minimum required for subsequent investments.

Sale of Plan Shares – A Plan participant has four options when submitting a sale request: Batch Order; Market Order; Day Limit Order; and Good-Til-Cancelled (“GTC”) Order. See the Plan Prospectus for detailed information and pricing on the different sales options. Proceeds checks are mailed after Trade + 2 days.

Investment Options

Full Dividend Reinvestment – Dividends earned on all Common Stock, both in the Plan account and Certificated account will be reinvested to purchase additional shares of Common Stock

Partial Dividend Reinvestment – Participants may designate a specific number of shares on which they wish to receive cash dividends, with dividends on the balance of shares being reinvested to purchase Common Stock.

Cash Investment Only – Dividends earned on all Common Stock will be paid directly to the investor either by check or direct deposit at the election of the shareholder.