Initial Statement of Beneficial Ownership

This filing reports the initial statement of beneficial ownership for Chung Kin Cheung, Chief Financial Officer of AAON, INC. The filing details a stock option grant for 5,211 shares of common stock, exercisable at $97.90, with an expiration date of April 20, 2036. The stock award vests ratably over the first three years from the grant date. Additionally, Mr. Cheung directly owns 2,034 shares of common stock following this transaction. The reporting period is April 20, 2026, and the signature date is April 30, 2026.