IDEXX officer Mazelsky proposes $17.7M share sale

The notice lists an aggregate market value of $17,678,196.60; the shares came from an issuer stock-option exercise paid in cash.

Available on EDGAR 11/04/2026 - 04:23 PM EST Accepted by SEC EDGAR 11/04/2026 - 04:22 PM EST Learn about SEC filing dates

Rhea-AI Filing Summary

IDEXX Laboratories, Inc. officer and director Jonathan Jay Mazelsky reported a proposed sale of 25,140 common shares, with an approximate sale date of November 4, 2026. The securities information lists an aggregate market value of $17,678,196.60. The shares were acquired from the issuer through a stock option exercise on November 4, 2026, with cash payment.

Key Figures

Proposed sale: 25,140 common shares Aggregate market value: $17,678,196.60 Shares outstanding: 78,786,265 shares

3 metrics

Proposed sale 25,140 common shares Approximate sale date: November 4, 2026

Aggregate market value $17,678,196.60 Proposed sale

Shares outstanding 78,786,265 shares IDEXX Laboratories, Inc.

Key Terms

Rule 144, Stock Option Exercise, Securities To Be Sold

3 terms

Rule 144 regulatory

"paragraph (a) of Rule 144"

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

Stock Option Exercise financial

"Stock Option Exercise"

A stock option exercise is the act of using a previously granted right to buy shares of a company's stock at a specific, predetermined price by paying that price and receiving the shares. It matters to investors because exercising changes who owns the shares (which can dilute existing ownership), can trigger taxable events and shift potential gains or losses, and affects voting power and the company’s outstanding share count—like turning a voucher into an actual product that becomes part of circulating supply.

Securities To Be Sold regulatory

"144: Securities To Be Sold"

FAQ

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How many IDXX shares did Jonathan Jay Mazelsky propose to sell?

Jonathan Jay Mazelsky reported a proposed sale of 25,140 common shares, with an aggregate market value of $17,678,196.60 and an approximate sale date of November 4, 2026.

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

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Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0001556270
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	IDEXX LABORATORIES, INC.
SEC File Number	000-19271
Address of Issuer	One IDEXX Drive Westbrook MAINE 04092
Phone	207-556-0300
Name of Person for Whose Account the Securities are To Be Sold	JONATHAN J MAZELSKY
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Officer
Relationship to Issuer	Director

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common	Morgan Stanley Smith Barney LLC Executive Financial Services 1 New York Plaza 8th Floor New York NY 10004	25140	17678196.60	78786265	11/04/2026	NASDAQ

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common	11/04/2026	Stock Option Exercise	Issuer			25140	11/04/2026	Cash

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Nothing to Report

144: Remarks and Signature

Remarks
Date of Notice	11/04/2026
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/ Jonathan Jay Mazelsky
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)