[Form 4] CLEAN HARBORS INC Insider Trading Activity

Rhea-AI Filing Summary

Clean Harbors Inc executive Rebecca Underwood reported a routine tax-related share disposition. She had 311 shares of Common Stock withheld at $290.74 per share to cover tax liabilities tied to vesting, as permitted under Rule 16b-3. After this withholding, she directly holds 18,373 shares of Clean Harbors common stock.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider Underwood Rebecca

Role PRESIDENT & EVP FACILITIES

Type	Security	Shares	Price	Value
Tax Withholding	Common Stock	311	$290.74	$90K

Holdings After Transaction: Common Stock — 18,373 shares (Direct, null)

Footnotes (1)

1. [object Object]

Key Figures

Shares withheld for taxes: 311 shares Price per share: $290.74 per share Shares owned after transaction: 18,373 shares +1 more

4 metrics

Shares withheld for taxes 311 shares Tax-withholding disposition on Common Stock

Price per share $290.74 per share Valuation used for 311-share tax withholding

Shares owned after transaction 18,373 shares Direct ownership following tax withholding

Tax-withholding shares (summary) 311 shares Form 4 transactionSummary taxWithholdingShares

Key Terms

tax-withholding disposition, Rule 16b3, Common Stock

3 terms

tax-withholding disposition financial

"transaction_action: "tax-withholding disposition" for 311 shares"

A tax-withholding disposition is an event or transaction—such as selling or transferring securities, exercising options, or receiving compensation—that triggers a requirement to hold back part of the payment and remit it to tax authorities. It matters to investors because it reduces the cash they receive immediately and can change the timing and amount of taxable income, like a cashier taking a portion of your sale proceeds to pay taxes before you get the rest.

Rule 16b3 regulatory

"Payment of tax liability by withholding of securities incident to vesting of securities in accordance with Rule 16b3"

Common Stock financial

"security_title: "Common Stock" in the Form 4 transaction"

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.

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 07/06/2026 - 03:11 PM Accepted by SEC EDGAR 07/06/2026 - 03:11 PM 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^*

Underwood Rebecca

(Last) (First) (Middle)

42 LONGWATER DR

(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)
	PRESIDENT & EVP FACILITIES

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
07/01/2026

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	07/01/2026		F		311(1)	D	$290.74	18,373	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 16b3

	/s/ Rebecca Underwood	07/06/2026
	** 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.
* Form 4: SEC 1474 (03-26)

FAQ

What insider transaction did Clean Harbors (CLH) report for Rebecca Underwood?

Clean Harbors reported that executive Rebecca Underwood had 311 shares of Common Stock withheld. The shares, valued at $290.74 each, were used to pay tax liabilities arising from vesting, leaving her with 18,373 shares directly owned.

Was the Clean Harbors (CLH) Form 4 transaction an open-market sale?

No, the Form 4 shows a tax-withholding disposition, not an open-market sale. 311 shares were withheld by the company to cover taxes on vesting, which is a routine administrative event for equity compensation.

How many Clean Harbors (CLH) shares does Rebecca Underwood hold after the filing?

Following the reported tax-withholding event, Rebecca Underwood directly holds 18,373 shares of Clean Harbors Common Stock. This figure is disclosed as her total direct ownership after the 311-share withholding transaction.

What was the price per share in the Clean Harbors (CLH) insider tax-withholding?

The tax-withholding disposition was recorded at $290.74 per share for 311 shares of Clean Harbors Common Stock. This price is used to value the shares applied toward the associated tax liability on vesting.

How does Rule 16b-3 apply to the Clean Harbors (CLH) Form 4 transaction?

The footnote states the tax payment occurred by withholding shares incident to vesting under Rule 16b-3. That rule generally exempts certain insider transactions, like equity compensation and related tax withholding, from short-swing profit liability rules.