Organon & Co.

Non-GAAP Financial Measures

This proxy contains“non-GAAP financial measures,” which are financial measures that either exclude or include amounts that are not excluded or included in the most directly comparable measures calculated and presented in accordance with U.S. generally accepted accounting principles (“GAAP”). Specifically, the company makes use of thenon-GAAP financial measures Adjusted EBITDA, Adjusted Net Income, and Adjusted diluted EPS, which are not recognized terms under GAAP and are presented only as a supplement to the company’s GAAP financial statements. This proxy also provides certain measures that exclude the impact of foreign exchange. We calculate foreign exchange by converting our current-period local currency financial results using the prior period average currency rates and comparing these adjusted amounts to our current-period results. The company believes that thesenon-GAAP financial measures help to enhance an understanding of the company’s financial performance. However, the presentation of these measures has limitations as an analytical tool and should not be considered in isolation, or as a substitute for the company’s results as reported under GAAP. Because not all companies use identical calculations, the presentations of thesenon-GAAP measures may not be comparable to other similarly titled measures of other companies.

The company usesnon-GAAP financial measures in its operational and financial decision making, and believes that it is useful to exclude certain items in order to focus on what it regards to be a more meaningful representation of the underlying operating performance of the business.

Revenues

Adjusted Revenue for AIP

Reconciliation of GAAP Income from Continuing Operations Before Income Taxes to Adjusted EBITDA

Reconciliation of GAAP Income from Continuing Operations Before Income Taxes to Non-GAAP Adjusted Net Income

SCAN TO VIEW MATERIALS & VOTE w ORGANON & CO. VOTE BY INTERNET 30 HUDSON STREET Before The Meeting—Go to www.proxyvote.com or scan the QR Barcode above FLOOR 33 Use the Internet to transmit your voting instructions and for electronic delivery of information. Vote JERSEY CITY, NJ 07302 by 11:59 P.M. Eastern Daylight Time on June 3, 2024. Have your proxy card in hand when you access the web site and follow the instructions to obtain your records and to create an electronic voting instruction form. During The Meeting—Go to www.virtualshareholdermeeting.com/OGN2024 You may attend the meeting via the Internet and vote during the meeting. Have the information that is printed in the box marked by the arrow available and follow the instructions. VOTE BYPHONE—1-800-690-6903 Use any touch-tone telephone to transmit your voting instructions. Vote by 11:59 P.M. Eastern Daylight Time on June 3, 2024. Have your proxy card in hand when you call and then follow the instructions. VOTE BY MAIL Mark, sign and date your proxy card and return it in the postage-paid envelope we have provided or return it to Vote Processing, c/o Broadridge, 51 Mercedes Way, Edgewood, NY 11717. Proxies submitted by mail must be received prior to the meeting date. TO VOTE, MARK BLOCKS BELOW IN BLUE OR BLACK INK AS FOLLOWS: V35180-P04602 KEEP THIS PORTION FOR YOUR RECORDS THIS PROXY CARD IS VALID ONLY WHEN SIGNED AND DATED. DETACH AND RETURN THIS PORTION ONLY ORGANON & CO. The Board of Directors recommends you vote FOR each of the following Class III Director Nominees: 1. Election of Directors Nominees: For Against Abstain 1a. Kevin Ali ! ! ! 1b. Martha E. McGarry ! ! ! 1c. Philip Ozuah, M.D., Ph. D. ! ! ! 1d. Shalini Sharp ! ! ! The Board of Directors recommends you vote FOR the following proposals: For Against Abstain 2. Approve, on anon-binding advisory basis, the compensation of Organon’s Named Executive Officers. ! ! ! 3. Ratify the appointment of PricewaterhouseCoopers LLP as Organon’s independent registered public accounting firm for 2024. ! ! ! NOTE: The proxies are authorized to vote in their discretion upon such other business as may properly come before the meeting or any adjournment or postponement thereof. Please sign exactly as your name(s) appear(s) hereon. When signing as attorney, executor, administrator, or other fiduciary, please give full title as such. Joint owners should each sign personally. All holders must sign. If a corporation or partnership, please sign in full corporate or partnership name by authorized officer. Signature [PLEASE SIGN WITHIN BOX] Date Signature (Joint Owners) Date

Important Notice Regarding the Availability of Proxy Materials for the Annual Meeting: The Notice and Proxy Statement and Annual Report are available at www.proxyvote.com V35181-P04602 ORGANON & CO. Annual Meeting of Shareholders June 4, 2024 9:00 a.m. (Eastern Daylight Time) This proxy is solicited on behalf of the Board of Directors The undersigned hereby appoints Kevin Ali, Matthew Walsh and Kirke Weaver as Proxies, each with the power to appoint his/her substitute, revoking all proxies previously given, and hereby authorizes them to represent and to vote all of the stock of Organon & Co. that the shareholder(s) is/are entitled to vote at the Annual Meeting of Shareholders to be held via webcast at www.virtualshareholdermeeting.com/OGN2024 at 9:00 a.m. Eastern Daylight Time on June 4, 2024, and at any adjournments or postponements thereof, upon the matters set forth on the reverse side, as designated, and upon such other matters as may properly come before the meeting. The shares represented by this proxy will be voted as directed by the shareholder and in accordance with the judgment of the Proxies upon any other matter that may properly come before the meeting and any adjournment or postponement thereof. If no specification is made, the shares will be voted FOR each nominee in Item 1 and FOR Items 2 and 3. Continued and to be signed on reverse side