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^*

TEPPER ROBERT I

(Last)

(First)

(Middle)

C/O THIRD ROCK VENTURES, LLC

29 NEWBURY STREET, 3RD FLOOR

(Street)

BOSTON

02116

(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)

X	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
02/03/2015

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	02/03/2015		J⁽¹⁾		1,215,054	D	$0	0	I	See footnote⁽²⁾
Common Stock	02/03/2015		J⁽³⁾		300,863	A	$0	300,863	I	See footnote⁽⁴⁾
Common Stock	02/03/2015		J⁽⁵⁾		300,863	D	$0	0	I	See footnote⁽⁴⁾
Common Stock	02/03/2015		J⁽⁶⁾		62,479	A	$0	89,017	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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)

Explanation of Responses:

1. Distribution of shares in kind by Third Rock Ventures, L.P. ("TRV")on a pro rata basis to its partners.

2. The shares are directly held by TRV. The general partner of TRV is Third Rock Ventures GP, L.P. ("TRV GP"). The general partner of TRV GP is TRV GP, LLC ("TRV GP LLC") and the Reporting Person is a Manager of TRV GP LLC, as such, each of TRV GP, TRV GP LLC and the Reporting Person exercises shared voting and investment power over the shares held of record by TRV. The Reporting Person disclaims beneficial ownership of the shares except to the extent of his pecuniary interest therein, if any.

3. TRV GP received shares distributed in kind by TRV on a pro rata basis to its partners.

4. The shares are directly held by TRV GP. As such, TRV GP LLC and the Reporting Person, as a Manager of TRV GP LLC, exercise voting and investment power over the shares held of record by TRV GP. The Reporting Person disclaims beneficial ownership of the shares except to the extent of his pecuniary interest therein, if any.

5. Distribution of shares in kind by TRV GP on a pro rata basis to its partners.

6. The Reporting Person received shares distributed in kind by TRV GP on a pro rata basis to its partners.

Remarks:

	/s/ Kevin Gillis by Power of Attorney for Robert I. Tepper, MD	02/04/2015
	** 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.
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