Perimeter Solutions (PRM) director sells 325,000 shares in open-market trades

Rhea-AI Filing Summary

Perimeter Solutions, Inc. director William N. Thorndike Jr. reported selling a total of 325,000 shares of common stock in open-market transactions. The sales took place over three days, with 125,000 shares sold on March 4, 2026, 100,000 shares on March 5, 2026, and 100,000 shares on March 6, 2026.

The reported weighted average sale prices were $24.26 on March 4, $24.06 on March 5, and $23.63 on March 6, 2026, with actual trade prices on each day ranging within the bands described in the footnotes. Following these transactions, Thorndike directly held 8,860,656 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

OMB APPROVAL

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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)
03/04/2026

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	03/04/2026		S		125,000	D	$24.26(1)	9,060,656	D
Common Stock	03/05/2026		S		100,000	D	$24.06(2)	8,960,656	D
Common Stock	03/06/2026		S		100,000	D	$23.63(3)	8,860,656	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 4, 2026. The prices of the shares sold pursuant to the transaction ranged from approximately $23.85 to $24.53 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 5, 2026. The prices of the shares sold pursuant to the transaction ranged from approximately $23.66 to $24.40 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.

3. Represents the weighted average price of the shares sold on March 6, 2026. The prices of the shares sold pursuant to the transaction ranged from approximately $23.37 to $23.99 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	03/06/2026
	** 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.

FAQ

What insider transaction did Perimeter Solutions (PRM) disclose in this Form 4?

Perimeter Solutions reported that director William N. Thorndike Jr. sold 325,000 shares of common stock in open-market transactions over three days in March 2026, while remaining a large shareholder after the trades with 8,860,656 shares held directly.

How many Perimeter Solutions (PRM) shares did William N. Thorndike Jr. sell?

William N. Thorndike Jr. sold a total of 325,000 Perimeter Solutions common shares, including 125,000 shares on March 4, 2026, 100,000 shares on March 5, 2026, and 100,000 shares on March 6, 2026, all reported as open-market sales.

What prices were reported for William N. Thorndike Jr.’s PRM share sales?

The sales used weighted average prices of $24.26 on March 4, 2026, $24.06 on March 5, 2026, and $23.63 on March 6, 2026. Footnotes explain that individual trade prices on each day fell within specified price ranges around those averages.

How many Perimeter Solutions (PRM) shares does William N. Thorndike Jr. hold after the sales?

After the reported open-market sales, William N. Thorndike Jr. directly holds 8,860,656 shares of Perimeter Solutions common stock. This post-transaction holding amount is taken from the Form 4 line item for the March 6, 2026 transaction.

Were the Perimeter Solutions (PRM) insider transactions direct or indirect holdings?

The Form 4 classifies all three transactions as involving direct ownership, coded as "D" for the nature of ownership. There are no footnote disclosures indicating indirect holdings through entities such as trusts, partnerships, or family investment vehicles.

What do the Form 4 footnotes say about the PRM sale prices?

Each footnote states that the reported sale price for that day is a weighted average. Actual trade prices ranged within specified bands, and the reporting person offers to provide full details on the number of shares sold at each separate price upon request.