UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): September 18, 2017

bluebird bio, Inc.

(Exact name of Registrant as Specified in Its Charter)

Registrant’s Telephone Number, Including Area Code: (339) 499-9300

Not Applicable

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instructions A.2. below):

Indicate by check mark whether the registrant is an emerging growth company as defined in as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

On September 18, 2017, the board of directors (the “Board”) of bluebird bio, Inc. (the “Company”), upon the recommendation of the Board’s nominating and corporate governance committee, appointed Mary Lynne Hedley, Ph.D. to the Board as a Class II director.   Dr. Hedley has not been appointed to any committees of the Board, as of the date of this Current Report on Form 8-K.

In connection with the appointment, on September 18, 2017, the Company granted Dr. Hedley a stock option to purchase 10,700 shares of the Company’s common stock, par value $0.01 per share (“Common Stock”), at a purchase price equal to the closing price per share of the Common Stock on the NASDAQ Global Select Market on September 18, 2017. Dr. Hedley was also granted on September 18, 2017 restricted stock units for 2,700 shares of Common Stock. The stock options and restricted stock units vest ratably over three years in annual installments.  

Dr. Hedley 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 Dr. Hedley and any other persons pursuant to which she was selected as a director.

On September 18, 2017, Dr. John Maraganore notified the Company of his resignation from the Board and the Compensation Committee of the Board, effective immediately.  Dr. Maraganore’s resignation was not caused by any disagreement with the Company on any matter relating to the Company’s operations, policies or practices.  

On September 20, 2017, the Company issued a press release announcing Dr. Hedley’s appointment to the Board. A copy of this press release is furnished as Exhibit 99.1 to this report on Form 8-K.

The information in this Item 7.01 and Exhibit 99.1 attached hereto is intended to be furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934 (the “Exchange Act”) or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933 or the Exchange Act, except as expressly set forth by specific reference in such filing.

Item 9.01Financial Statements and Exhibits.

(d) Exhibits

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.