Heather Kiessling - 16 Oct 2026 Form 4 Insider Report for ASP Isotopes Inc. (ASPI)

Reporting relationship: Chief Financial Officer
Issuer ticker: ASPI
Reported as of: 16 Oct 2026
Net transaction value: -$47,808
SEC form: 4
Accepted by SEC: 21 Oct 2026, 21:45:10 UTC
Prior SEC filing: 02 Jul 2026
Source filing: View source filing
Reporting owner signature: /s/ Donald Ainscow, as attorney-in-fact

Filing notes and source

Key filing fact

Heather Kiessling filed Form 4 for ASP Isotopes Inc. (ASPI) on 21 Oct 2026.

Key facts

This page summarizes Heather Kiessling's Form 4 filing for ASP Isotopes Inc. (ASPI).
1 reported transaction and 0 derivative rows are listed below.
Accepted by SEC: 21 Oct 2026, 21:45.

Change

Previous filing in this sequence was filed on 02 Jul 2026.
Current net transaction value: -$47,808.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0002026548 Primary reporting owner

Kiessling Heather

Relationship: Chief Financial Officer
Address: C/O ASP ISOTOPES INC., 2200 ROSS AVENUE, SUITE 4575E, DALLAS
Signature: /s/ Donald Ainscow, as attorney-in-fact
Signature date: 21 Oct 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

ASPI transaction

Common Stock

Sale

Transaction value: -$47,808
Shares: -21,830
Change %: -1.4%
Price: $2.19
Shares after: 1,504,422
Date: 16 Oct 2026
Ownership: Direct
Footnotes: F1

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 1 footnote

Footnote F1

Represents shares automatically sold by ASP Isotopes Inc.(the "Company") on behalf of the reporting person pursuant to a mandatory sell-to-cover provision in the award agreement required to cover minimum statutory tax withholding obligations. The sale does not represent a discretionary trade by the reporting person.