What was the price range for the ASP Isotopes COO’s share sale?

The weighted average sale price was $5.205 per share, with individual trades executed between $5.055 and $5.52. The filing notes the COO will provide complete details of shares sold at each price within this range upon request to the company, shareholders, or SEC staff.

Tax-related share sale by ASP Isotopes (ASPI) COO under 10b5-1 plan

Filing Impact

(Moderate)

Filing Sentiment

(Negative)

Form Type

Rhea-AI Filing Summary

ASP Isotopes Inc. COO Robert Ainscow reported an open-market sale of 22,500 shares of Common Stock at a weighted average price of $5.205 per share. According to the disclosure, this was a "sell to cover" transaction under a Rule 10b5-1 trading plan adopted on June 9, 2025 to cover tax withholding obligations tied to vesting restricted stock awards. After the sale, he directly held 1,490,317 shares, so the transaction represents a small portion of his overall position.

Insider Trade Summary 10b5-1

Net Seller: 22,500 shares ($117,113)

Net Sell 1 txn

Insider Ainscow Robert

Role COO

Sold 22,500 shs ($117K)

Type	Security	Shares	Price	Value
Sale	Common Stock	22,500	$5.205	$117K

Holdings After Transaction: Common Stock — 1,490,317 shares (Direct)

Footnotes (1)

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. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $5.055 to $5.52, 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: 22,500 shares Weighted average sale price: $5.205 per share Post-transaction holdings: 1,490,317 shares +1 more

4 metrics

Shares sold 22,500 shares Open-market sale on April 16, 2026

Weighted average sale price $5.205 per share Common Stock, open-market sale

Post-transaction holdings 1,490,317 shares Common Stock directly owned after sale

Trade price range $5.055 to $5.52 Range of prices for individual sale transactions

Key Terms

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

4 terms

Rule 10b5-1 trading plan regulatory

"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.

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 awards financial

"tax withholding obligations in connection with the vesting of restricted stock awards"

Restricted stock awards are company shares given to employees or executives that cannot be sold or transferred until certain conditions — like staying with the company for a set time or meeting performance targets — are met, like a gift that is locked in a safe until rules are satisfied. Investors care because these awards tie management’s pay to company performance, can increase the number of shares outstanding when they become tradable (dilution), and may signal expected future selling pressure or commitment to long-term growth.

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.

Form 4 Insider Transactions: What Each Field Means →

04/17/2026 - 09:55 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^*

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)
04/16/2026

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	04/16/2026		S⁽¹⁾		22,500	D	$5.205⁽²⁾	1,490,317	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. 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.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $5.055 to $5.52, 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.

	/s/ Donald Ainscow, as attorney-in-fact	04/17/2026
	** 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 transaction did ASP Isotopes (ASPI) report for its COO?

ASP Isotopes reported that COO Robert Ainscow sold 22,500 shares of Common Stock at a weighted average price of $5.205. The filing states this was a sell-to-cover transaction linked to tax withholding on vesting restricted stock awards under a pre-established Rule 10b5-1 plan.

Why did ASP Isotopes COO Robert Ainscow sell 22,500 ASPI shares?

The sale was disclosed as a "sell to cover" to satisfy tax withholding obligations from vesting restricted stock awards. It was executed under a Rule 10b5-1 trading plan, meaning the trades were pre-arranged rather than timed discretionarily with market movements.

How many ASP Isotopes (ASPI) shares does the COO hold after this Form 4?

Following the reported transaction, COO Robert Ainscow directly owned 1,490,317 shares of ASP Isotopes Common Stock. This indicates the 22,500 shares sold represent a relatively small fraction of his total reported holdings after the tax-related sale.

Was the ASP Isotopes COO’s stock sale under a Rule 10b5-1 plan?

Yes. The filing states the "sell to cover" trades were effected pursuant to a Rule 10b5-1 trading plan adopted on June 9, 2025. Such plans pre-schedule transactions, providing structure for sales and reducing the significance of trade timing as an indicator of insider sentiment.