On March 24, 2023, bluebird bio, Inc.'s board of directors appointed Richard Paulson to the Board as a Class III director, effective April 3, 2023. Mr. Paulson is eligible to participate in the Company's Non-Employee Director Compensation Policy, including receipt of an annual retainer of $45,000 for his Board service, and an initial award, effective April 3, 2023, of stock option to purchase 7,500 shares of the Company's common stock, par value $0.01 per share at a purchase price equal to the closing price per share of the Common Stock on the Nasdaq Global Select Market on April 3, 2023, and 4,663 restricted stock units. The stock options and restricted stock units will vest ratably over three years in annual installments.

Mr. Paulson will also enter into the Company's standard indemnification agreement for directors and officers. Mr. Paulson is not a party to any transaction with the Company that would require disclosure under Item 404(a) of Regulation S-K, and there are no arrangements or understandings between Mr. Paulson and any other persons pursuant to which he was selected as a director.