FLATIRON BIO, LLC 401(K) PLAN

Profit-sharing plan.

This plan or any part of it is intended to meet the conditions of 29 CFR 2550.404c-1 (shifting investment responsibility to participants).

Participants have the opportunity to direct the investment of all of the assets allocated to their individual accounts regardless of whether 29 CFR 2550.404c-1 is intended to be met.

Cash or deferred arrangement described in Code section 401(k) that is part of a qualified defined contribution plan under which employees may elect to defer part of their compensation or receive these amounts in cash.

Plan provides for automatic enrollment in plan that has elective contributions deducted from payroll.

Total or partial participant-directed account plan where plan uses a default investment account for participants who fail to direct assets in their account.

Plan covering self-employed individuals.

A master prototype or volume submitter plan that is the subject of a favorable opinion or advisory letter from the IRS.