X0306 4 2022-05-11 0 0000874716 IDEXX LABORATORIES INC /DE IDXX 0001094176 SZOSTAK M ANNE ONE IDEXX DRIVE WESTBROOK ME 04092 1 0 0 0 Common Stock 2022-05-11 4 M 0 224 0 A 224 D Common Stock 6557 I 2021 Szostak IDEXX GRAT Common Stock 660 I Trust of M. Anne Szostak Non-Qualified Stock Option (right-to-buy) 333.90 2022-05-11 4 A 0 945 A 2032-05-10 Common Stock 945 945 D Restricted Stock Unit 2022-05-11 4 A 0 344 A Common Stock 344 568 D Restricted Stock Unit 2022-05-11 4 M 0 224 D Common Stock 224 344 D The reporting person is the settlor and trustee of the 2021 Szostak IDEXX GRAT (the "GRAT"). The GRAT is irrevocable, and the reporting person disclaims beneficial ownership of these shares except to the extent of her pecuniary interest therein. The reporting person is the settlor of the Trust of M. Anne Szostak ("Trust") and the trustee of the Trust, has power to direct the distribution of Trust assets, and has the power to revoke or amend the Trust. The reporting person has a pecuniary interest in the shares transferred to the Trust. Grant of option to buy shares of IDEXX Laboratories, Inc. common stock that vest in one installment on the one year anniversary of the date of grant or on the date of the 2023 annual meeting of shareholders, whichever event is earlier. Each restricted stock unit represents a contingent right to receive one share of IDEXX Laboratories, Inc. common stock. Restricted stock units vest in in one installment on the one year anniversary of the date of grant or on the date of the 2023 annual meeting of shareholders, whichever event is earlier. Each restricted stock unit represents a contingent right to receive one share of IDEXX Laboratories, Inc. common stock. These restricted stock units vested in in one installment on the one year anniversary of the date of grant or on the date of the 2022 annual meeting of shareholders, whichever event was earlier. Not applicable. /s/ Lily J. Lu, Attorney-in-Fact for M. Anne Szostak 2022-05-13