Transactions in Connection with Share Buy-back Program Company Announcement COPENHAGEN, Denmark

Transactions in Connection with Share Buy-back Program

Company Announcement

COPENHAGEN, Denmark; May 21, 2024 - Genmab A/S (Nasdaq: GMAB). On March 15, 2024, Genmab announced the initiation of a share buy-back program to repurchase up to DKK 3.5 billion worth of shares.

The share buy-back program is expected to be completed no later than December 16, 2024.

The following transactions were executed under the program from May 13, 2024 to May 17, 2024:

Details of each transaction are included as an appendix to this announcement.

Transactions in Connection with Share Buy-back Program

Following these transactions, Genmab holds 1,573,136 shares as treasury shares, corresponding to 2.38% of the total share capital and voting rights.

The share buy-back program is undertaken in accordance with Regulation (EU) No. 596/2014 ( MAR') and the Commission Delegated Regulation (EU) 2016/1052, also referred to as the "Safe Harbour Regulation." Further details on the terms of the share buy-back program can be found in our company announcement no. 22 dated March 15, 2024.

Genmab is an international biotechnology company with a core purpose guiding its unstoppable team to strive towards improving the lives of patients through innovative and differentiated antibody therapeutics. For 25 years, its passionate, innovative and collaborative team has invented next-generation antibody technology platforms and leveraged translational, quantitative, and data sciences, resulting in a proprietary pipeline including bispecific T-cell engagers, next-generation immune checkpoint modulators, effector function enhanced antibodies, and antibody-drug conjugates. To help develop and deliver novel antibody therapies to patients, Genmab has formed 20+ strategic partnerships with biotechnology and pharmaceutical companies. By 2030, Genmab's vision is to transform the lives of people with cancer and other serious diseases with knock-your-socks-off (KYSO ) antibody medicines.

Marisol Peron, Senior Vice President, Global Communications & Corporate Affairs

T: +1 609 524 0065; E: mmp@genmab.com

Andrew Carlsen, Vice President, Head of Investor Relations

T: +45 3377 9558; E: acn@genmab.com

This Company Announcement contains forward looking statements. The words "believe," "expect," "anticipate," "intend" and "plan" and similar expressions identify forward looking statements. Actual results or performance may differ materially from any future results or performance expressed or implied by such statements. The important factors that could cause our actual results or performance to differ materially include, among others, risks associated with pre-clinical and clinical development of products, uncertainties related to the outcome and conduct of clinical trials including unforeseen safety issues, uncertainties related to product manufacturing, the lack of market acceptance of our products, our inability to manage growth, the competitive environment in relation to our business area and markets, our inability to attract and retain suitably qualified personnel, the unenforceability or lack of protection of our patents and proprietary rights, our relationships with affiliated entities, changes and developments in technology which may render our products or technologies obsolete, and other factors. For a further discussion of these risks, please refer to the risk management sections in Genmab's most recent financial reports, which are available on www.genmab.com and the risk factors included in Genmab's most recent Annual Report on Form 20-F and other filings with the U.S. Securities and Exchange Commission (SEC), which are available at www.sec.gov. Genmab does not undertake any obligation to update or revise forward looking statements in this Company Announcement nor to confirm such statements to reflect subsequent events or circumstances after the date made or in relation to actual results, unless required by law.

Genmab A/S and/or its subsidiaries own the following trademarks: Genmab ; the Y-shaped Genmab logo ; Genmab in combination with the Y-shaped Genmab logo ; HuMax ; DuoBody ; HexaBody ; DuoHexaBody , HexElect and KYSO .