COO of ASP Isotopes (NASDAQ: ASPI) sells 25,000 shares

Rhea-AI Filing Summary

ASP Isotopes Inc. COO Robert Ainscow reported an open‑market sale of 25,000 shares of common stock on March 6, 2026. The sale was executed at a weighted average price of $4.511 per share, with individual trades ranging from $4.42 to $4.58.

These sales were made under a pre‑arranged Rule 10b5-1 trading plan adopted on December 13, 2024, indicating they were scheduled in advance. Following this transaction, Ainscow directly holds 1,512,817 shares of ASP Isotopes common stock.

Insider Trade Summary 10b5-1

Net Seller: 25,000 shares ($112,775)

Net Sell 1 txn

Insider Ainscow Robert

Role COO

Sold 25,000 shs ($113K)

Type	Security	Shares	Price	Value
Sale	Common Stock	25,000	$4.511	$113K

Holdings After Transaction: Common Stock — 1,512,817 shares (Direct)

Footnotes (1)

1. Represents sales effected pursuant to a Rule 10b5-1 trading plan adopted by the filing person on December 13, 2024. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $4.42 to $4.58, 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 2.

Key Figures

Shares sold: 25,000 shares Weighted average sale price: $4.511 per share Sale price range: $4.42–$4.58 per share +3 more

6 metrics

Shares sold 25,000 shares Open-market sale on March 6, 2026

Weighted average sale price $4.511 per share Average for 25,000 shares sold

Sale price range $4.42–$4.58 per share Multiple transactions within this range

Shares held after transaction 1,512,817 shares Direct ownership following sale

Plan adoption date December 13, 2024 Rule 10b5-1 trading plan used for sale

Transaction code S Sale in open market or private transaction

Key Terms

Rule 10b5-1 trading plan, weighted average price, open-market sale, Common Stock

4 terms

Rule 10b5-1 trading plan regulatory

"Represents sales effected pursuant to a Rule 10b5-1 trading plan adopted by the filing person"

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.

weighted average price financial

"The price reported in Column 4 is a weighted average price."

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.

open-market sale financial

"transaction_action": "open-market sale""

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

Common Stock financial

"security_title": "Common Stock""

Common stock represents ownership shares in a company, giving investors a stake in its success and a say in important decisions through voting rights. It is the most common type of stock traded on markets and can provide income through dividends, as well as potential for value growth. For investors, holding common stock means sharing in the company’s profits and risks.

Form 4 Insider Transactions: What Each Field Means →

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).

X

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^*

Ainscow Robert

(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)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	COO

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/13/2026

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)
			Code	V	Amount	(A) or (D)	Price
Common Stock	03/06/2026		S(1)		25,000	D	$4.511(2)	1,512,817	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)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Represents sales effected pursuant to a Rule 10b5-1 trading plan adopted by the filing person on December 13, 2024.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $4.42 to $4.58, 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 2.

Remarks:

	/s/ Donald Ainscow, as attorney-in-fact	04/13/2026
	** 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)

FAQ

What insider transaction did ASP Isotopes (ASPI) report for its COO?

ASP Isotopes COO Robert Ainscow reported selling 25,000 shares of common stock. The transaction occurred on March 6, 2026, as an open-market sale under a pre-arranged Rule 10b5-1 trading plan adopted in December 2024.

At what price did the ASP Isotopes (ASPI) COO sell his shares?

The COO’s 25,000 ASP Isotopes shares were sold at a weighted average price of $4.511. Individual trades took place in multiple transactions at prices ranging from $4.42 to $4.58 per share, according to the disclosed footnote.

How many ASP Isotopes (ASPI) shares does the COO hold after this sale?

After the reported sale, COO Robert Ainscow directly holds 1,512,817 ASP Isotopes common shares. This figure reflects his position immediately following the 25,000-share open-market sale disclosed in the Form 4 filing.

Was the ASP Isotopes (ASPI) COO sale part of a Rule 10b5-1 plan?

Yes. The filing states the sales were effected under a Rule 10b5-1 trading plan adopted on December 13, 2024. Such plans schedule trades in advance, helping separate routine portfolio management from discretionary market-timing decisions.

What does the price range in the ASP Isotopes (ASPI) COO sale represent?

The filing notes that the reported $4.511 price is a weighted average. The 25,000 shares were sold in multiple transactions at prices between $4.42 and $4.58, and detailed trade-by-trade information is available upon request from the company or regulators.