Clean Harbors (CLH) Co-CEO logs tax withholding and forfeited restricted stock

Rhea-AI Filing Summary

Clean Harbors Inc. Co-CEO Eric W. Gerstenberg reported two non-derivative dispositions of common stock on March 13, 2026. The first involved 977 shares used for payment of tax liability by withholding shares upon vesting, at a reference price of $288.93 per share, in accordance with Rule 16b. The second was a disposition of 2,166 shares to the issuer, representing restricted stock forfeited because the company did not achieve performance targets under its Long Term Equity Incentive Program. A separate footnote indicates a correction to the total number of shares held, but the updated post-transaction holdings are not stated in this report.

Insider Trade Summary

Net Seller: 3,143 shares

Net Sell 2 txns

Insider GERSTENBERG ERIC W

Role CO-CEO

Type	Security	Shares	Price	Value
Tax Withholding	Common Stock F1, F2	977	$288.93	$282K
Disposition	Common Stock F3, F2	2,166	$0.00	$0.00

Holdings After Transaction: Common Stock — 60,857 shares (Direct)

Footnotes (3)

1. F1. Payment of tax liability by withholding of securities incident to vesting of securities in accordance with Rule 16b.
2. F2. Correction to Total Number of Shares Held.
3. F3. Shares of restricted stock forfeited due to the Company not achieving performance targets under its Long Term Equity Incentive Program.

Key Figures

Shares withheld for taxes: 977 shares Tax withholding reference price: $288.93 per share Restricted shares forfeited: 2,166 shares +2 more

5 metrics

Shares withheld for taxes 977 shares Common stock withheld on March 13, 2026 to pay tax liability on vesting

Tax withholding reference price $288.93 per share Price associated with 977-share tax withholding transaction

Restricted shares forfeited 2,166 shares Restricted stock forfeited to issuer for not meeting performance targets

Tax-liability transaction count 1 transaction One code F transaction for payment of tax liability by withholding securities

Issuer disposition count 1 transaction One code D disposition of restricted stock to the issuer

Key Terms

Rule 16b, Long Term Equity Incentive Program, restricted stock, disposition to issuer, +1 more

5 terms

Rule 16b regulatory

"Payment of tax liability by withholding of securities incident to vesting of securities in accordance with Rule 16b."

Long Term Equity Incentive Program financial

"performance targets under its Long Term Equity Incentive Program."

restricted stock financial

"Shares of restricted stock forfeited due to the Company not achieving performance targets"

Shares granted to an individual that carry limits on transfer or sale until certain conditions are met, such as staying with the company for a set time or hitting performance targets. Think of them as a locked gift that gradually opens; for investors they matter because they affect how many shares may enter the market later, signal management incentives and potential dilution, and reveal confidence in future company performance.

disposition to issuer financial

"transaction_code_description": "Disposition to issuer""

payment of tax liability by withholding securities financial

"transaction_code_description": "Payment of tax liability by delivering or withholding securities""

FAQ

What insider transactions did CLH Co-CEO Eric Gerstenberg report on March 13, 2026?

On March 13, 2026, Co-CEO Eric W. Gerstenberg reported two dispositions of Clean Harbors (CLH) common stock: 977 shares withheld to cover tax liabilities on vesting and 2,166 restricted shares forfeited back to the company for missed performance targets.

How many CLH shares were withheld for Eric Gerstenberg’s tax obligations?

Eric Gerstenberg had 977 CLH shares withheld to pay tax liabilities related to vesting equity, at a reference price of $288.93 per share. This was characterized as payment of tax liability by withholding securities under Rule 16b.

Why were 2,166 Clean Harbors (CLH) restricted shares forfeited by Eric Gerstenberg?

The 2,166 restricted shares were forfeited because Clean Harbors did not achieve performance targets under its Long Term Equity Incentive Program. The transaction is reported as a disposition to the issuer with no cash price per share listed.

Does the amended Form 4 for CLH correct Eric Gerstenberg’s share holdings?

Yes. A footnote states there is a correction to the total number of shares held by Eric Gerstenberg. However, the amended Form 4/A does not provide a specific updated share balance after the reported transactions.

Were Eric Gerstenberg’s CLH transactions under a Rule 10b5-1 trading plan?

No. The Form 4/A indicates the Rule 10b5-1 checkbox is not checked, and no footnote describes a pre-arranged trading plan. The reported dispositions relate to tax withholding and performance-based forfeiture of restricted stock.

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 08/14/2026 - 09:18 AM Accepted by SEC EDGAR 08/14/2026 - 09:17 AM Learn about SEC filing dates

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^*

GERSTENBERG ERIC W

(Last) (First) (Middle)

C/O CLEAN HARBORS ENVIRON. SERVICES INC.

42 LONGWATER DRIVE

(Street)

NORWELL MASSACHUSETTS 02061

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
CLEAN HARBORS INC [ CLH ]

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
03/13/2026

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)
03/17/2026

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	03/13/2026		F		977(1)	D	$288.93	63,023(2)	D
Common Stock	03/13/2026		D		2,166(3)	D	$0	60,857(2)	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. Payment of tax liability by withholding of securities incident to vesting of securities in accordance with Rule 16b.

2. Correction to Total Number of Shares Held.

3. Shares of restricted stock forfeited due to the Company not achieving performance targets under its Long Term Equity Incentive Program.

	/s/ Eric W. Gerstenberg	08/14/2026
	** 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)