Were ASP Isotopes (ASPI) CEO share sales made under a Rule 10b5-1 trading plan?

Yes. The filing states the share sales were "sell to cover" transactions under a Rule 10b5-1 trading plan adopted on December 30, 2025. They were executed specifically to cover tax withholding obligations tied to quarterly vesting of a restricted stock award.

ASP Isotopes (ASPI) CEO reports tax-cover share sales and 2.23M-share grant

Filing Impact

(Very High)

Filing Sentiment

(Negative)

Form Type

Rhea-AI Filing Summary

ASP Isotopes Inc. Chairman and CEO Paul Elliot Mann reported both share sales and a new equity award. He sold a total of 251,275 shares of common stock in three open-market transactions at weighted average prices of $7.76, $7.88, and $8.29 per share. According to the disclosure, these were "sell to cover" trades under a Rule 10b5-1 plan to cover tax withholding on quarterly vesting of a restricted stock award. Mann also received a grant of 2,233,555 shares of common stock under his employment agreement, which will vest in four equal installments over a one-year period beginning on March 1, 2026.

Insider Trade Summary 10b5-1

Net Seller: 251,275 shares ($2,004,337)

Net Sell 4 txns

Insider Mann Paul Elliot

Role Chairman and CEO

Sold 251,275 shs ($2.00M)

Type	Security	Shares	Price	Value
Grant/Award	Common Stock	2,233,555	$0.00	--
Sale	Common Stock	83,758	$7.88	$660K
Sale	Common Stock	83,758	$8.29	$694K
Sale	Common Stock	83,759	$7.76	$650K

Holdings After Transaction: Common Stock — 9,830,940 shares (Direct, null)

Footnotes (1)

This award of common stock was issued to the reporting person pursuant to his Employment Agreement dated October 4, 2021, as amended on December 20, 2022 and April 5, 2024, and shall vest (subject to compliance with applicable vesting conditions) in four equal installments over a one-year period beginning on March 1, 2026. Represents "sell to cover" sales effected pursuant to a Rule 10b5-1 trading plan adopted by the filing person on December 30, 2025 to cover tax withholding obligations in connection with the quarterly vesting of a restricted stock award. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $7.49 to $8.14, 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 this footnote. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $7.81 to $8.52, 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 this footnote. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $7.53 to $8.13, 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 this footnote.

Key Figures

Shares sold: 251,275 shares Sale price 1: $7.76 per share Sale price 2: $8.29 per share +4 more

7 metrics

Shares sold 251,275 shares Total common shares sold in three open-market transactions

Sale price 1 $7.76 per share Weighted average price for 83,759 shares sold

Sale price 2 $8.29 per share Weighted average price for 83,758 shares sold

Sale price 3 $7.88 per share Weighted average price for 83,758 shares sold

Stock grant 2,233,555 shares Common stock award under CEO employment agreement

Post-transaction holdings 9,830,940 shares Common shares held directly after reported transactions

Vesting start date March 1, 2026 Beginning of four-installment vesting period for stock grant

Key Terms

Rule 10b5-1 trading plan, sell to cover, restricted stock award, weighted average price, +1 more

5 terms

Rule 10b5-1 trading plan financial

"Represents "sell to cover" sales effected pursuant to a Rule 10b5-1 trading plan adopted by the filing person on December 30, 2025"

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

sell to cover financial

"Represents "sell to cover" sales effected pursuant to a Rule 10b5-1 trading plan"

Sell to cover is when a person who receives company stock through options or awards sells just enough shares immediately to pay required taxes, exercise costs, or fees, keeping the rest. Think of it like cashing part of a bonus to cover the tax bill so you can keep the remainder. For investors, it can create predictable small selling pressure and slightly change the number of shares actually held by insiders without increasing long‑term dilution.

restricted stock award financial

"to cover tax withholding obligations in connection with the quarterly vesting of a restricted stock award"

A restricted stock award is company shares given to an employee or executive that cannot be sold or fully owned until certain conditions—like staying with the company for a set time or hitting performance targets—are met. Think of it as a gift that only becomes yours after you fulfill specific obligations; for investors, these awards matter because they can increase the total shares outstanding when they vest, reveal how management is being paid and motivated, and create potential selling pressure when restrictions lift.

weighted average price financial

"The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions"

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

vesting conditions financial

"shall vest (subject to compliance with applicable vesting conditions) in four equal installments"

Vesting conditions are the rules that determine when someone earning company stock or stock options actually gains the right to keep or sell them, typically based on staying with the company for a set time or meeting performance targets. Think of it like keys that unlock gradually — some unlock by calendar date, others only after agreed milestones. Investors care because vesting shapes management incentives, the timing of share sales, and the number of shares that can enter the market, which can affect a company's valuation and ownership mix.

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Form 4 Insider Transactions: What Each Field Means →

06/03/2026 - 09:45 PM

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a 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). See Instruction 10.

1. Name and Address of Reporting Person^*

Mann Paul Elliot

(Last)

(First)

(Middle)

C/O ASP ISOTOPES INC.

2200 ROSS AVENUE, SUITE 4575E

(Street)

DALLAS

TEXAS

75201

(City)

(State)

(Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
ASP Isotopes Inc. [ ASPI ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director	10% Owner
X	Officer (give title below)	Other (specify below)
	Chairman and CEO

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/28/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	05/28/2026⁽¹⁾		A		2,233,555	A	⁽¹⁾	9,830,940	D
Common Stock	06/01/2026		S⁽²⁾		83,758	D	$7.88⁽³⁾	9,747,182	D
Common Stock	06/02/2026		S⁽²⁾		83,758	D	$8.29⁽⁴⁾	9,663,424	D
Common Stock	06/03/2026		S⁽²⁾		83,759	D	$7.76⁽⁵⁾	9,579,845	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)

Explanation of Responses:

1. This award of common stock was issued to the reporting person pursuant to his Employment Agreement dated October 4, 2021, as amended on December 20, 2022 and April 5, 2024, and shall vest (subject to compliance with applicable vesting conditions) in four equal installments over a one-year period beginning on March 1, 2026.

2. Represents "sell to cover" sales effected pursuant to a Rule 10b5-1 trading plan adopted by the filing person on December 30, 2025 to cover tax withholding obligations in connection with the quarterly vesting of a restricted stock award.

3. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $7.49 to $8.14, 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 this footnote.

4. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $7.81 to $8.52, 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 this footnote.

5. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $7.53 to $8.13, 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 this footnote.

	/s/ Donald Ainscow, as attorney-in-fact	06/03/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

Source: View Original Filing on SEC EDGAR

FAQ

What insider transactions did ASP Isotopes (ASPI) report for Paul Elliot Mann?

ASP Isotopes reported that Chairman and CEO Paul Elliot Mann sold 251,275 common shares in three open-market transactions and received a grant of 2,233,555 shares. The filing shows these combined sales and awards as part of his ongoing equity compensation and related tax obligations.

How many ASP Isotopes (ASPI) shares did Paul Elliot Mann sell and at what prices?

Paul Elliot Mann sold 251,275 ASP Isotopes common shares in three trades at weighted average prices of $7.76, $7.88, and $8.29 per share. These transactions were disclosed as open-market sales executed to cover tax withholding obligations on vesting restricted stock.

What equity award did ASP Isotopes (ASPI) grant to its CEO in this Form 4?

ASP Isotopes granted CEO Paul Elliot Mann 2,233,555 shares of common stock under his employment agreement. The award will vest in four equal installments over a one-year period beginning March 1, 2026, subject to compliance with applicable vesting conditions detailed in the agreement.

How many ASP Isotopes (ASPI) shares does Paul Elliot Mann hold after these transactions?

After the reported transactions, Paul Elliot Mann beneficially owned 9,830,940 shares of ASP Isotopes common stock directly. This figure reflects his position following both the tax-related sales and the large stock grant disclosed in the Form 4 filing.

How will the new ASP Isotopes (ASPI) stock grant to the CEO vest over time?

The 2,233,555-share stock grant will vest in four equal installments over one year, starting March 1, 2026. Each quarter during that year, one-quarter of the award becomes vested, assuming the vesting conditions in the CEO’s employment agreement continue to be satisfied.