On November 8, 2024, Pinnacle West opened its ATM Program, pursuant to which Pinnacle West may sell, from time to time, up to $900 million of its common stock through an at-the-market equity distribution program, which includes the ability to enter into forward sale agreements. Approximately $434 million of common stock is available to be sold under the ATM Program, which takes into account the forward sale agreements in effect as of March 31, 2026.

As of March 31, 2026, Pinnacle West had nine outstanding forward sale agreements under its ATM Program (collectively, the “ATM Forward Sale Agreements”). These agreements relate to approximately $466 million, on a gross basis, of common stock and may be settled at Pinnacle West’s discretion by issuing shares at the applicable forward sales price or, alternatively, by delivering cash in lieu of shares. On April 1, 2026, Pinnacle West entered into a tenth forward sale agreement relating to a total of $100 million, on a gross basis, of common stock, with a maturity date of September 30, 2027.

The following table presents information about the outstanding ATM Forward Sale Agreements as of March 31, 2026 based on their contractual terms at the time each agreement was entered into, including the applicable forward sale prices and related aggregate contractual values, which may differ from the gross amount of common stock referenced above (dollars in thousands, except price per share):


ATM Forward Sale Agreements	Maturity Date (a)	Number of Shares	Forward Sales Price Per Share (b)			Aggregate Value

November 2024	June 30, 2026	552,833	$	89.73		$	49,606
March 2025	September 14, 2026	544,959	$	90.83		$	49,499
August 2025	February 16, 2027	543,001	$	91.21		$	49,527
September 2025	February 22, 2027	558,622	$	88.69		$	49,544
January 2026	July 2, 2027	119,553	$	89.88		$	10,745
March 2026	September 3, 2027	646,674	$	99.52		$	64,357
March 2026	September 10, 2027	490,537	$	100.94		$	49,515
March 2026	September 18, 2027	488,813	$	101.28		$	49,507
March 2026	September 30, 2027	916,930	$	98.12		$	89,969
		4,861,922	$	95.08	(c)	$	462,269

In addition to the ATM Forward Sale Agreements, Pinnacle West also has Forward Sale Agreements that were entered into on February 28, 2024 (the “February 2024 Forward Sale Agreements”). These agreements may be settled at Pinnacle West’s discretion by issuing shares of Pinnacle West common stock and receiving cash, if any, at the then-applicable forward sales price. The terms of the February 2024 Forward Sale Agreements also allow Pinnacle West, at its option, to settle the agreements with the counterparties by delivering cash, in lieu of shares. The February 2024 Forward Sale Agreements were partially settled in December 2024, September 2025, and December 2025. In August 2025, APS amended the February 2024 Forward Sale Agreements with Wells Fargo Bank, National Association, to extend the maturity date of those forward confirmations to December 31, 2026.


February 2024 Forward Sale Agreements	Number of Shares		Forward Sales Price Per Share			Aggregate Value

Initial Price	11,240,601		$	64.51	(a)	$	725,131

Settlements
December 23, 2024	5,377,115	(b)	$	64.17		$	345,049	(c)
September 4, 2025	243,186	(b)	$	63.12		$	15,350	(c)
December 18, 2025	1,193,950	(b)	$	62.82		$	75,004	(c)

In June 2024, Pinnacle West issued $525 million of 4.75% Convertible Senior Notes due 2027, which are senior unsecured obligations of Pinnacle West and will mature on June 15, 2027. Interest is payable semiannually in arrears on June 15 and December 15 of each year, beginning on December 15, 2024.

Prior to March 15, 2027, the holders of the Convertible Notes may elect at their option to convert all or any portion of their Convertible Notes under the following limited circumstances:

•during any calendar quarter (and only during such calendar quarter), if the sale price of Pinnacle West common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter, is greater than or equal to 130% of the conversion price on each applicable trading day;

•during the five business day period after any 10 consecutive trading day period (“Measurement Period”) in which the trading price per $1,000 principal amount of Convertible Notes for each trading day of the Measurement Period was less than 98% of the product of the last reported sale price of Pinnacle West common stock and the conversion rate on such trading day; or

On or after March 15, 2027, until the maturity date, the holders of the Convertible Notes may elect at their option to convert all or any portion of their notes. Upon conversion, Pinnacle West will pay cash up to the aggregate principal amount of the Convertible Notes converted and at Pinnacle West’s sole discretion, pay or deliver cash, shares of Pinnacle West common stock or a combination of both, in respect to the remainder, if any, of Pinnacle West’s conversion obligation in excess of the aggregate principal amount of the Convertible Notes being converted. The initial conversion rate, which is subject to certain adjustments as set forth in the indenture, is 10.8338 shares of common stock per $1,000 principal amount

of Convertible Notes, which is equivalent to an initial conversion price of approximately $92.30 per share. The conversion rate is not subject to adjustment for any accrued and unpaid interest.

If Pinnacle West undergoes a fundamental change, as defined in the Convertible Notes’ indenture, then, subject to certain conditions, holders of the Convertible Notes may require Pinnacle West to repurchase for cash all or any portion of its Convertible Notes at a repurchase price equal to 100% of the principal amount of the Convertible Notes to be repurchased, plus accrued and unpaid interest to, but excluding, the fundamental change repurchase date.

As of March 31, 2026, the conditions allowing holders to convert their Convertible Notes were not met, and as a result, the Convertible Notes were classified as long term debt on Pinnacle West’s Condensed Consolidated Balance Sheets with a carrying amount of $525 million, net of approximately $3 million in unamortized debt issuance costs. The estimated fair value of the Convertible Notes as of March 31, 2026 was approximately $597 million (Level 2 within the fair value hierarchy).

As of March 31, 2026, based on Pinnacle West’s average stock price and the relevant terms of the Convertible Notes, there were shares of Pinnacles West’s common stock included in diluted EPS relating to the potential conversion of the Convertible Notes, but no shares included in basic EPS.


	Three Months Ended March 31,
	2026		2025
Net income (loss) attributable to common shareholders	$	32,920	$	(4,644)

Weighted average common shares outstanding — basic	121,360		119,594
Net effect of dilutive securities:
Contingently issuable performance shares and restricted stock units	444		498
Dilutive shares related to equity forward sale agreements (a)	1,722		1,669
Dilutive shares related to convertible debt instruments (b)	252		—
Total contingently issuable shares (c)	2,418		2,167

Weighted average common shares outstanding — diluted	123,778		121,761
Earnings per weighted-average common share outstanding
Net income (loss) attributable to common shareholders — basic	$	0.27	$	(0.04)
Net income (loss) attributable to common shareholders — diluted	$	0.27	$	(0.04)

(a) For the three months ended March 31, 2026 and 2025 the diluted weighted-average common shares excludes 16,127 and 4,636 shares, respectively relating to the ATM Program. These potentially issuable shares were excluded from the calculation of diluted shares as their inclusion would have been antidilutive.

(b) For the three months ended March 31, 2026 and 2025 the diluted weighted-average common shares excludes 0 and 192,754 shares, respectively relating to the Convertible Notes. These potentially issuable shares were excluded from the calculation of diluted shares as their inclusion would have been antidilutive.

(c) No contingently issuable shares were excluded from the calculation of diluted weighted-average common shares outstanding for the three months ended March 31, 2026. For the three months ended March 31, 2025, 2,167,000 contingently issuable shares were excluded from the calculation of diluted weighted-average common shares outstanding, as their inclusion would have been antidilutive due to the Net Loss results.