X0508 4 2025-12-18-05:00 false 0001921865 ASP Isotopes Inc. ASPI 0002026548 Kiessling Heather C/O ASP ISOTOPES INC. 601 PENNSYLVANIA AVENUE NW SUITE 900 WASHINGTON DC 20004 false true false false Chief Financial Officer false Common Stock 2025-12-18-05:00 4 S false 80000 5.798 D 732500 D The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $5.73 to $5.885, inclusive. The reporting person undertakes to provide ASP Isotopes Inc. (the "Company"), any stockholder of the Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in Footnote 1. /s/ Donald Ainscow, as attorney-in-fact 2025-12-29-05:00