Perimeter Solutions (PRM) director Thorndike sells 325,000 common shares

Rhea-AI Filing Summary

Perimeter Solutions, Inc. director William N. Thorndike Jr. reported open-market sales of a total of 325,000 shares of Common Stock over three trading days. He sold 134,000 shares on March 9, 2026 in two trades of 90,043 and 34,957 shares at weighted average prices of $23.18 and $23.85 per share, 100,000 shares on March 10, 2026 at a weighted average price of $23.63 per share, and 100,000 shares on March 11, 2026 at a weighted average price of $23.18 per share. The footnotes state that each daily price is a weighted average within intraday ranges, and full breakdowns are available upon request. Following these transactions, he directly holds 8,535,656 shares of Perimeter Solutions common stock.

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

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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^*

Thorndike William N Jr

(Last) (First) (Middle)

C/O PERIMETER SOLUTIONS, INC.

8000 MARYLAND AVE., SUITE 350

(Street)

CLAYTON MO 63105

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Perimeter Solutions, Inc. [ PRM ]

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

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

3. Date of Earliest Transaction (Month/Day/Year)
03/09/2026

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

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

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

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	03/09/2026		S		90,043	D	$23.18(1)	8,770,613	D
Common Stock	03/09/2026		S		34,957	D	$23.85(2)	8,735,656	D
Common Stock	03/10/2026		S		100,000	D	$23.63(3)	8,635,656	D
Common Stock	03/11/2026		S		100,000	D	$23.18(4)	8,535,656	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 the weighted average price of the shares sold on March 9, 2026. The prices of the shares sold pursuant to the transaction ranged from approximately $22.71 to $23.71 per share. The Reporting Person, upon request, will provide the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares sold at each separate price.

2. Represents the weighted average price of the shares sold on March 9, 2026. The prices of the shares sold pursuant to the transaction ranged from approximately $23.73 to $23.95 per share. The Reporting Person, upon request, will provide the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares sold at each separate price.

3. Represents the weighted average price of the shares sold on March 10, 2026. The prices of the shares sold pursuant to the transaction ranged from approximately $23.33 to $23.97 per share. The Reporting Person, upon request, will provide the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares sold at each separate price.

4. Represents the weighted average price of the shares sold on March 11, 2026. The prices of the shares sold pursuant to the transaction ranged from approximately $22.72 to $23.40 per share. The Reporting Person, upon request, will provide the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares sold at each separate price.

Remarks:

	/s/ Noriko Yokozuka, as Attorney-in-Fact	03/11/2026
	** 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).
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FAQ

What insider transactions did Perimeter Solutions (PRM) report for William N. Thorndike Jr.?

Perimeter Solutions reported that director William N. Thorndike Jr. sold a total of 325,000 common shares in open-market transactions over three days in March 2026, according to a Form 4 insider filing detailing each trade and resulting holdings.

Over what dates did PRM director William N. Thorndike Jr. sell shares?

The reported sales occurred on March 9, 10, and 11, 2026. Across these three trading days, Thorndike completed four separate open-market transactions in Perimeter Solutions common stock, all disclosed in the same Form 4 filing.

How many Perimeter Solutions (PRM) shares did Thorndike sell and at what prices?

Thorndike sold 325,000 common shares in total: 134,000 shares on March 9, 100,000 on March 10, and 100,000 on March 11, 2026, at weighted average prices around $23.18, $23.63, and $23.18 per share, respectively.

How many PRM shares does William N. Thorndike Jr. hold after these sales?

After the reported transactions, Thorndike directly holds 8,535,656 shares of Perimeter Solutions common stock. This post-transaction ownership figure is stated in the Form 4 for the last trade date and reflects his remaining direct position.

Were the PRM insider sales executed at a single price or multiple prices?

Each day’s reported price is a weighted average, not a single execution price. Footnotes explain that individual trades on each date occurred within price ranges, and full breakdowns of shares sold at each price are available upon request.

Does the Form 4 for Perimeter Solutions show any derivative transactions for Thorndike?

The Form 4 shows no derivative transactions for Thorndike. All reported activity involves non-derivative Common Stock sales, and the derivative summary section indicates zero derivative exercises or holdings in this particular filing.