Paul Elliot Mann - Sep 8, 2025 Form 4 Insider Report for ASP Isotopes Inc. (ASPI)

Role
Chief Executive Officer, Director, 10%+ Owner
Signature
/s/ Donald Ainscow, as attorney-in-fact
Stock symbol
ASPI
Transactions as of
Sep 8, 2025
Transactions value $
-$1,371,519
Form type
4
Date filed
9/10/2025, 09:00 PM
Previous filing
Apr 17, 2025
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Mann Paul Elliot Chief Executive Officer, Director, 10%+ Owner C/O ASP ISOTOPES INC., 601 PENNSYLVANIA AVENUE NW, SUITE 900, WASHINGTON /s/ Donald Ainscow, as attorney-in-fact 2025-09-10 0001744816

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction ASPI Common Stock Sale -$691K -81.1K -1.11% $8.53 7.23M Sep 8, 2025 Direct F1, F2
transaction ASPI Common Stock Options Exercise $432K +216K +2.99% $2.00 7.45M Sep 9, 2025 Direct
transaction ASPI Common Stock Tax liability -$432K -50.6K -0.68% $8.53 7.4M Sep 9, 2025 Direct F3
transaction ASPI Common Stock Options Exercise $2M +1M +13.51% $2.00 8.4M Sep 9, 2025 Direct
transaction ASPI Common Stock Tax liability -$2M -234K -2.79% $8.53 8.17M Sep 9, 2025 Direct F3
transaction ASPI Common Stock Sale -$680K -81.1K -0.99% $8.39 8.08M Sep 9, 2025 Direct F1, F4

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
transaction ASPI Employee Stock Option (right to buy) Options Exercise $0 -216K -100% $0.00 0 Sep 9, 2025 Common Stock 216K $2.00 Direct F5
transaction ASPI Employee Stock Option (right to buy) Options Exercise $0 -1M -100% $0.00 0 Sep 9, 2025 Common Stock 1M $2.00 Direct F6
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Buy Plan / Sale Plan: These are also open market purchases/sales of shares, but in this case the transaction is part of a trading plan. Rule 10b5-1 allows insiders to setup a trading plan to buy/sell stocks over a certain period of time. Since the purchases/sales are predetermined, this protects the insiders from violating insider trading law.

Transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

Explanation of Responses:

Id Content
F1 Represents "sell to cover" sales effected pursuant to a Rule 10b5-1 trading plan adopted by the filing person on June 9, 2025 to cover tax withholding obligations in connection with the vesting of restricted stock awards.
F2 The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $8.135 to $8.575, inclusive. The reporting person undertakes to provide 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 2.
F3 Represents shares withheld by the Company in connection with net share settlement to satisfy the exercise price associated with the reporting person's exercise of employee stock options. No shares were sold by the reporting person to satisfy the exercise price or any tax liability.
F4 The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $8.135 to $8.575, inclusive. The reporting person undertakes to provide 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 2.
F5 These options vested in a single installment 12 months after the grant date. The option was granted on April 4, 2022.
F6 These options vested in thirty-six equal installments beginning on the last day of month after the option's grant date. The option was granted on June 10, 2022.