Insider Transaction Report for Heather Kiessling

Heather Kiessling, Chief Financial Officer of ASP Isotopes Inc., reported a transaction involving 21,830 shares of Common Stock on October 16, 2026. The shares were automatically sold to cover minimum statutory tax withholding obligations, not as a discretionary trade. The sale price was $2.19 per share, resulting in a post-transaction ownership of 1,504,422 shares. This transaction is reported on Form 4, with footnote F1 providing further details on the mandatory sell-to-cover provision.