Merrimack Pharmaceuticals, Inc. Announces Anticipated Final Cash Dividend Amount of Initial Liquidating Distribution, Subject to Receipt of Stockholder Approval of Plan of Dissolution

Merrimack Pharmaceuticals, Inc. (Nasdaq: MACK) (“Merrimack” or the “Company”) today announced that the Board of Directors intends to declare a liquidating cash dividend in the amount of $15.10 per share, if stockholder approval of the Plan of Dissolution is obtained at the Special Meeting of Stockholders held on May 10, 2024. The dividend is expected to be paid on or about May 17, 2024, to stockholders of record on May 10, 2024.

We cannot predict with certainty the amount of liquidating distributions to our stockholders. Based on the information currently available to us, we estimate that the aggregate amount initially to be distributed to stockholders will be $15.10 per share. Total actual distributions, if any, could be higher or lower than $15.10 per share and the estimate for the amount to be initially distributed to stockholders could change. It is also possible that any distribution could be followed in the future by additional distributions, if it is determined that any reserved amounts no longer need to be reserved. Also, although not anticipated currently, additional amounts could be distributed in the event additional milestones are achieved under the Ipsen and Elevation Oncology agreements.

IMPORTANT ADDITIONAL INFORMATION AND WHERE TO FIND IT

In connection with the proposed liquidation and Dissolution of the Company (the “Dissolution”) and the Plan of Dissolution, the Company filed a definitive proxy statement (the “Proxy Statement”) with the Securities and Exchange Commission (the “SEC”) on March 21, 2024. BEFORE MAKING ANY VOTING DECISION, INVESTORS AND SECURITY HOLDERS ARE URGED TO READ THE DEFINITIVE PROXY STATEMENT, ANY AMENDMENTS OR SUPPLEMENTS THERETO, ANY OTHER SOLICITING MATERIALS AND ANY OTHER DOCUMENTS TO BE FILED WITH THE SEC IN CONNECTION WITH THE PROPOSED DISSOLUTION, THE PLAN OF DISSOLUTION AND RELATED MATTERS, AND/OR INCORPORATED BY REFERENCE IN THE PROXY STATEMENT BECAUSE THEY CONTAIN OR WILL CONTAIN IMPORTANT INFORMATION ABOUT MERRIMACK PHARMACEUTICALS, INC., THE PROPOSED DISSOLUTION, THE PLAN OF DISSOLUTION AND RELATED MATTERS. Stockholders may obtain a free copy of the Proxy Statement and the other relevant materials, and any other documents filed by the Company with the SEC, at the SEC’s website at http://www.sec.gov or on the “Investors” section of the Company’s website at www.merrimack.com.