SEC FORM 4 SEC Form 4
FORM 4 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940
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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
1. Name and Address of Reporting Person*
Gregory Philip D

(Last) (First) (Middle)
C/O BLUEBIRD BIO, INC.
60 BINNEY STREET

(Street)
CAMBRIDGE MA 02142

(City) (State) (Zip)
2. Issuer Name and Ticker or Trading Symbol
bluebird bio, Inc. [ BLUE ]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
Director 10% Owner
X Officer (give title below) Other (specify below)
Chief Scientific Officer
3. Date of Earliest Transaction (Month/Day/Year)
04/02/2018
4. If Amendment, Date of Original Filed (Month/Day/Year)
6. Individual or Joint/Group Filing (Check Applicable Line)
X Form filed by One Reporting Person
Form filed by More than One Reporting Person
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4)
Code V Amount (A) or (D) Price
Common Stock 04/02/2018 M 1,250 A $50.51 31,522 D
Common Stock 04/02/2018 S(1) 1,250 D $167.642(2) 30,272 D
Common Stock 04/02/2018 S(1) 300 D $169.0183(3) 29,972 D
Common Stock 04/02/2018 S(1) 700 D $170.5 29,272 D
Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 6. Date Exercisable and Expiration Date (Month/Day/Year) 7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Stock Option (right to buy) $50.51 04/02/2018 M 1,250 (4) 03/01/2026 Common Stock 1,250 $0.00 17,000 D
Explanation of Responses:
1. The sales reported in the Form 4 were effected pursuant to a 10b5-1 trading plan adopted by the reporting person on March 17, 2017.
2. The range in prices for the transaction reported on this line was $167.30 to $168.20. The average weighted price was $167.6420. The reporting person will provide, upon request by the SEC, the issuer or security holder of the issuer, full information regarding the number of shares sold at each separate price.
3. The range in prices for the transaction reported on this line was $169.00 to $169.05. The average weighted price was $169.0183. The reporting person will provide, upon request by the SEC, the issuer or security holder of the issuer, full information regarding the number of shares sold at each separate price
4. This option vests over a four-year period, at a rate of twenty-five percent (25%) on January 4, 2017 and in 36 equal monthly installments thereafter.
Remarks:
/s/ Jason F. Cole, Attorney-in-Fact 04/04/2018
** Signature of Reporting Person Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
LIMITED POWER OF ATTORNEY

The undersigned hereby constitutes and appoints each of Jason F. Cole,
Jeffrey T. Walsh, Kory Wentworth, and Helen Fu, and each of them individually,
and with full power of substitution, the undersigned's true and lawful
attorney-in-fact to:

     (1)     Complete and execute for and on behalf of the undersigned, in the
             undersigned's capacity as an officer, director and/or ten
             percent (10%) shareholder of bluebird bio, Inc., a Delaware
             corporation (the "Company") any and all instruments, certificates
             and documents required to be executed on behalf of the undersigned
             as an individual or on behalf of the undersigned's company or
             partnership, as the case may be, pursuant to Section 13 and
             Section 16 of the Securities Exchange Act of 1934, as amended (the
            "Exchange Act") or the rules and regulations thereunder;

     (2)     Do and perform any and all acts for and on behalf of the
             undersigned which may be necessary or desirable to complete and
             execute any such instruments, certificates or documents required to
             be filed pursuant to Sections 13 and 16 of the Exchange Act or
             the rules or regulations thereunder and timely file such forms with
             the United States Securities and Exchange Commission and any
             stock exchange or similar
 authority; and

     (3)     Take any other action of any type whatsoever in connection with the
             foregoing which, in the opinion of such attorney-in-fact, may be of
             benefit to, in the best interest of, or legally required by, the
             undersigned, it being understood that the documents executed by any
             such attorney-in-fact on behalf of the undersigned pursuant to this
             Power of Attorney shall be in such form and shall contain such
             terms and conditions as such attorney-in-fact may approve in such
             attorney-in-fact's discretion.

     The undersigned hereby grants to each such attorney-in-fact, acting singly,
full power and authority to do and perform any and every act which is necessary,
proper or desirable to be done in the exercise of any of the rights and powers
herein granted, as fully to all intents and purposes as the undersigned might or
could do if personally present, with full power of substitution or revocation,
hereby ratifying and confirming all that any such attorney-in-fact, or any such
attorney-in-fact's substitute or substitutes, shall lawfully do or cause to be
done by virtue of this Power of Attorney and the rights and powers herein
granted.

      The undersigned acknowledges that each of the foregoing attorneys-in-fact,
in serving in such capacity at the request of the undersigned, are not assuming,
nor is the Company assuming, any of the undersigned's responsibilities to comply
with Section 13 or Section 16 of the Exchange Act or the rules or regulations
thereunder.  The undersigned hereby agrees to indemnify each attorney-in-fact
and the Company from and against any demand, damage, loss, cost or expense
arising from any false or misleading information provided by the undersigned to
such attorney-in fact.

     This Power of Attorney shall remain in full force and effect until the
undersigned is no longer required to file any instruments, certificates and
documents pursuant to Section 13 and 16 of the Exchange Act or the rules or
regulations thereunder with respect to the undersigned's holdings of and
transactions in securities issued by the Company, unless earlier revoked by the
undersigned in a signed writing delivered to the foregoing attorneys-in-fact.

	IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be
executed as of March 7, 2018.

                              /s/ Philip D. Gregory
                              Philip D. Gregory