Sec Form 4 Filing - Britt Irene Chang @ IDEXX LABORATORIES INC /DE - 2023-09-01

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Britt Irene Chang 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 _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) IDEXX LABORATORIES, INC., ONE IDEXX DRIVE 3. Date of Earliest Transaction (MM/DD/YY) 09/01/2023 (Street) WESTBROOK, ME04092 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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 of Derivative Security: 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 Restricted Stock Unit ( 1 ) ( 2 ) 09/01/2023 A 208 ( 2 ) ( 2 ) Common Stock 208 $ 0 208 D Non-Qualified Stock Option (right-to-buy) ( 1 ) $ 511.29 09/01/2023 A 493 ( 3 ) 08/31/2033 Common Stock 493 $ 0 493 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Britt Irene Chang IDEXX LABORATORIES, INC. ONE IDEXX DRIVE WESTBROOK, ME04092 X Signatures /s/ Lily J. Lu, Attorney-in-Fact for Irene Chang Britt 09/06/2023 Signature of Reporting Person Date

Explanation of Responses:

( 1 )This equity grant represents pro rata equity compensation earned by the reporting person as a non-employee Director from her election to the IDEXX Laboratories, Inc. Board of Directors on July 11, 2023 until the 2024 annual meeting of stockholders. ( 2 )Each restricted stock unit represents a contingent right to receive one share of IDEXX Laboratories, Inc. common stock. Restricted stock units vest in one installment on the date of the 2024 annual meeting of stockholders or May 17, 2024, whichever event occurs earlier. ( 3 )Grant of option to buy shares of IDEXX Laboratories, Inc. common stock that vests in one installment on May 17, 2024 or on the date of the 2024 annual meeting of stockholders, whichever event is earlier.

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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