Company: PRME
Filing Date: 2025-07-02
Form Type: PRE 14A
Source: 0001193125-25-155000
Chunk: 9

Company: Prime Medicine, Inc.
Filing Date: 2025-07-02
Form: PRE 14A
Chunk 9
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 as a vote “against” Proposal 2. If any other matter is presented at the Special Meeting, your proxy provides that your shares will be voted by the proxy holder named in the proxy card in accordance with his or her best judgement. At the time this proxy statement was first made available, we knew of no matters that needed to be acted on at the Special Meeting, other than those discussed in this proxy statement. Our Board’s Voting Recommendations Our Board recommends that you vote:

| • |     | “FOR” the approval of the repricing of certain outstanding stock options that have been 
 granted under the 2019 Plan and/or the 2022 Plan (Proposal 1); and                      |

| • |     | “FOR” the approval of a proposal to adjourn the Special Meeting to a later date, if necessary                                                                                                                                                       
 or appropriate, to permit further solicitation and vote of additional proxies in the event that there are insufficient votes for, or otherwise in connection with, the approval of the Option Repricing Proposal at the time of the Special Meeting 
 (Proposal 2).                                                                                                                                                                                                                                       |

If any other matter is properly brought before the Special Meeting, the Company – through the individuals named in the Company’s proxy card and acting as the “proxy holder,” or his or her designee, and pursuant to the blanket authorization granted under the proxy – will vote your shares on that matter in accordance with the discretion and judgment of the proxy holder. Required Votes to Approve Each Proposal As a stockholder, you are entitled to cast one vote per share for the proposal to approve: (i) the repricing of certain outstanding stock options that have been granted under the 2019 Plan and/or the 2022 Plan (Proposal 1); and (ii) a proposal to adjourn the Special Meeting to a later date, if necessary or appropriate, to permit further solicitation and vote of additional proxies in the event that there are insufficient votes for, or otherwise in connection with, the approval of the Option Repricing Proposal at the time of the Special Meeting (Proposal 2), but you may not cumulate your votes (in other words, you may not cast votes representing two times the number of your shares entitled to vote on each such proposal). 5

The following table summarizes the minimum vote needed to approve each proposal and the effect of abstentions and broker non-votes,if any:

| Proposal         |     | Voting      
 Options     |     | Board      
 Recommends |     | Vote Required                                                                                                                                                                                             |     |