IDEXX Executive Chair Mazelsky sells 25,140 shares

The option grant vested in five annual installments beginning February 14, 2019, with a listed expiration date of February 13, 2028.

Available on EDGAR 11/05/2026 - 05:02 PM EST Accepted by SEC EDGAR 11/05/2026 - 05:01 PM EST Learn about SEC filing dates

Rhea-AI Filing Summary

IDEXX Laboratories Executive Chair of the Board Jonathan Jay Mazelsky exercised 25,140 non-qualified stock options on November 4, 2026, at an exercise price of $178.26 per share, acquiring 25,140 common shares. He also sold 25,140 common shares in 13 reported transactions that day; reported per-share transaction prices ranged from $698.2625 to $711.9475. No Rule 10b5-1 plan is reported.

Insider Trade Summary

Exercise and Sale: 25,140 shares ($13.20M approx. pre-tax spread)

Exercise and Sale 15 txns

Insider MAZELSKY JONATHAN JAY

Role Executive Chair of the Board

Sold 25,140 shs ($17.68M)

Approx. gross sale proceeds $17.68M

Approx. exercise cost $4.48M

Approx. pre-tax spread $13.20M

Share of Position Sold 23.1%

Type	Security	Shares	Price	Value
Exercise	Non-Qualified Stock Option (right-to-buy) F14, F13	25,140	--	--
Exercise	Common Stock	25,140	$178.26	$4.48M
Sale	Common Stock F1	1,945	$698.2625	$1.36M
Sale	Common Stock F2	4,075	$699.3278	$2.85M
Sale	Common Stock F3	1,667	$700.325	$1.17M
Sale	Common Stock F4	4,540	$701.3564	$3.18M
Sale	Common Stock F5	2,136	$702.2107	$1.50M
Sale	Common Stock F6	3,950	$703.449	$2.78M
Sale	Common Stock	240	$705.59	$169K
Sale	Common Stock F7	840	$707.00	$594K
Sale	Common Stock F8	1,840	$707.8445	$1.30M
Sale	Common Stock F9	1,300	$709.0019	$922K
Sale	Common Stock F10	1,501	$710.1207	$1.07M
Sale	Common Stock F11	775	$711.3085	$551K
Sale	Common Stock F12	331	$711.9475	$236K

Holdings After Transaction: Non-Qualified Stock Option (right-to-buy) — 0 contracts (Direct); Common Stock — 83,803.302 shares (Direct)

Holdings Before and After: Non-Qualified Stock Option (right-to-buy), 25,140 to 0 contracts (Direct); Common Stock, 83,803.302 to 83,803.302 shares (Direct)

Other Insiders: 3 other insiders reported open-market sales of this stock in the 30 days up to this filing.

Footnotes (14)

1. F1. Represents the weighted average price of the shares sold ranging from a low of $697.80 to a high of $698.77 per share. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares purchased at each separate price.
2. F2. Represents the weighted average price of the shares sold ranging from a low of $698.92 to a high of $699.89 per share. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares purchased at each separate price.
3. F3. Represents the weighted average price of the shares sold ranging from a low of $700.00 to a high of $700.80 per share. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares purchased at each separate price.
4. F4. Represents the weighted average price of the shares sold ranging from a low of $701.005 to a high of $701.96 per share. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares purchased at each separate price.
5. F5. Represents the weighted average price of the shares sold ranging from a low of $702.00 to a high of $702.81 per share. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares purchased at each separate price.
6. F6. Represents the weighted average price of the shares sold ranging from a low of $703.04 to a high of $703.99 per share. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares purchased at each separate price.
7. F7. Represents the weighted average price of the shares sold ranging from a low of $706.60 to a high of $707.16 per share. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares purchased at each separate price.
8. F8. Represents the weighted average price of the shares sold ranging from a low of $707.645 to a high of $708.59 per share. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares purchased at each separate price.
9. F9. Represents the weighted average price of the shares sold ranging from a low of $708.65 to a high of $709.46 per share. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares purchased at each separate price.
10. F10. Represents the weighted average price of the shares sold ranging from a low of $709.815 to a high of $710.63 per share. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares purchased at each separate price.
11. F11. Represents the weighted average price of the shares sold ranging from a low of $710.82 to a high of $711.73 per share. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares purchased at each separate price.
12. F12. Represents the weighted average price of the shares sold ranging from a low of $711.845 to a high of $712.34 per share. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares purchased at each separate price.
13. F13. Grant of option to buy shares of Issuer common stock that vested in five annual installments beginning February 14, 2019.
14. F14. Not applicable.

Key Figures

Options exercised: 25,140 options Exercise price: $178.26 per share Common shares acquired: 25,140 shares +2 more

5 metrics

Options exercised 25,140 options November 4, 2026

Exercise price $178.26 per share Options exercised on November 4, 2026

Common shares acquired 25,140 shares November 4, 2026

Common shares sold 25,140 shares Across 13 reported transactions on November 4, 2026

Reported per-share sale prices $698.2625–$711.9475 per share Reported transactions on November 4, 2026

Key Terms

Non-Qualified Stock Option, weighted average price, annual installments

3 terms

Non-Qualified Stock Option financial

"Non-Qualified Stock Option (right-to-buy)"

A non-qualified stock option (NSO) is a contract that lets an employee or service provider buy company shares at a fixed price for a set period, like a voucher to purchase stock later at today’s price. It matters to investors because exercising NSOs creates ordinary income for the holder and can increase share count, affecting a company’s earnings and ownership mix; think of it as a future sale that can dilute existing shareholders and has immediate tax consequences for the recipient.

weighted average price financial

"weighted average price of the shares sold"

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.

annual installments financial

"vested in five annual installments beginning February 14, 2019"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

How many IDEXX shares did Jonathan Jay Mazelsky sell?

Jonathan Jay Mazelsky sold 25,140 IDEXX Laboratories common shares on November 4, 2026, in 13 reported transactions. The reported per-share transaction prices ranged from $698.2625 to $711.9475. No Rule 10b5-1 plan is reported.

How many IDEXX stock options did Jonathan Jay Mazelsky exercise, and at what price?

Jonathan Jay Mazelsky exercised 25,140 non-qualified stock options on November 4, 2026, at an exercise price of $178.26 per share, acquiring 25,140 common shares. The option grant had a listed expiration date of February 13, 2028.

When did Jonathan Jay Mazelsky's IDEXX option grant begin vesting?

Jonathan Jay Mazelsky's option grant vested in five annual installments beginning February 14, 2019.

AI-generated analysis. How Rhea-AI works. Not financial advice.

Form 4 Insider Transactions: What Each Field Means →

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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^*

MAZELSKY JONATHAN JAY

(Last) (First) (Middle)

ONE IDEXX DRIVE

(Street)

WESTBROOK MAINE 04092

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
IDEXX LABORATORIES INC /DE [ IDXX ]

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

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Executive Chair of the Board

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
11/04/2026

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	11/04/2026		M		25,140	A	$178.26	108,943.302	D
Common Stock	11/04/2026		S		1,945	D	$698.2625(1)	106,998.302	D
Common Stock	11/04/2026		S		4,075	D	$699.3278(2)	102,923.302	D
Common Stock	11/04/2026		S		1,667	D	$700.325(3)	101,256.302	D
Common Stock	11/04/2026		S		4,540	D	$701.3564(4)	96,716.302	D
Common Stock	11/04/2026		S		2,136	D	$702.2107(5)	94,580.302	D
Common Stock	11/04/2026		S		3,950	D	$703.449(6)	90,630.302	D
Common Stock	11/04/2026		S		240	D	$705.59	90,390.302	D
Common Stock	11/04/2026		S		840	D	$707(7)	89,550.302	D
Common Stock	11/04/2026		S		1,840	D	$707.8445(8)	87,710.302	D
Common Stock	11/04/2026		S		1,300	D	$709.0019(9)	86,410.302	D
Common Stock	11/04/2026		S		1,501	D	$710.1207(10)	84,909.302	D
Common Stock	11/04/2026		S		775	D	$711.3085(11)	84,134.302	D
Common Stock	11/04/2026		S		331	D	$711.9475(12)	83,803.302	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
Non-Qualified Stock Option (right-to-buy)	$178.26	11/04/2026		M			25,140	(13)	02/13/2028	Common Stock	25,140	(14)	0	D

Explanation of Responses:

1. Represents the weighted average price of the shares sold ranging from a low of $697.80 to a high of $698.77 per share. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares purchased at each separate price.

2. Represents the weighted average price of the shares sold ranging from a low of $698.92 to a high of $699.89 per share. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares purchased at each separate price.

3. Represents the weighted average price of the shares sold ranging from a low of $700.00 to a high of $700.80 per share. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares purchased at each separate price.

4. Represents the weighted average price of the shares sold ranging from a low of $701.005 to a high of $701.96 per share. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares purchased at each separate price.

5. Represents the weighted average price of the shares sold ranging from a low of $702.00 to a high of $702.81 per share. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares purchased at each separate price.

6. Represents the weighted average price of the shares sold ranging from a low of $703.04 to a high of $703.99 per share. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares purchased at each separate price.

7. Represents the weighted average price of the shares sold ranging from a low of $706.60 to a high of $707.16 per share. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares purchased at each separate price.

8. Represents the weighted average price of the shares sold ranging from a low of $707.645 to a high of $708.59 per share. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares purchased at each separate price.

9. Represents the weighted average price of the shares sold ranging from a low of $708.65 to a high of $709.46 per share. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares purchased at each separate price.

10. Represents the weighted average price of the shares sold ranging from a low of $709.815 to a high of $710.63 per share. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares purchased at each separate price.

11. Represents the weighted average price of the shares sold ranging from a low of $710.82 to a high of $711.73 per share. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares purchased at each separate price.

12. Represents the weighted average price of the shares sold ranging from a low of $711.845 to a high of $712.34 per share. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares purchased at each separate price.

13. Grant of option to buy shares of Issuer common stock that vested in five annual installments beginning February 14, 2019.

14. Not applicable.

Remarks:

	/s/ Lily J. Lu, Attorney-in-Fact for Jonathan Jay Mazelsky	11/05/2026
	** 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)