SEC FORM 3

SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

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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1. Name and Address of Reporting Person^*

Mulder Geert-Jan

(Last)

(First)

(Middle)

C/O CO?PERATIVE AAC LS U.A.

PO BOX 5187

(Street)

NAARDEN

1410 AD

(City)

(State)

(Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
06/18/2013

3. Issuer Name and Ticker or Trading Symbol
bluebird bio, Inc. [ BLUE ]

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

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

5. 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 Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
1. Title of Derivative Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
Series A-1 Convertible Preferred Stock	⁽¹⁾	⁽¹⁾	Common Stock	139,395	⁽¹⁾	I	See footnote⁽²⁾
Series A-2 Convertible Preferred Stock	⁽³⁾	⁽³⁾	Common Stock	331,158	⁽³⁾	I	See footnote⁽²⁾
Series B Preferred Convertible Preferred Stock	⁽⁴⁾	⁽⁴⁾	Common Stock	561,470	⁽⁴⁾	I	See footnote⁽²⁾
Series C Preferred Convertible Preferred Stock	⁽⁵⁾	⁽⁵⁾	Common Stock	70,196	⁽⁵⁾	I	See footnote⁽²⁾
Series D Preferred Convertible Preferred Stock	⁽⁶⁾	⁽⁶⁾	Common Stock	52,902	⁽⁶⁾	I	See footnote⁽²⁾
Warrant to Purchase Series A-1 Stock (right to buy)	⁽⁷⁾	11/16/2015	Series A-1 Convertible Preferred Stock⁽⁸⁾	14,934	$12.55	I	See footnote⁽²⁾
Warrant to Purchase Series A-1 Stock (right to buy)	⁽⁷⁾	10/26/2016	Series A-1 Convertible Preferred Stock⁽⁸⁾	9,956	$12.55	I	See footnote⁽²⁾
Warrant to Purchase Series A-1 Stock (right to buy)	⁽⁷⁾	05/03/2017	Series A-1 Convertible Preferred Stock⁽⁸⁾	32,856	$12.55	I	See footnote⁽²⁾
Warrant to Purchase Series A-1 Stock (right to buy)	⁽⁷⁾	08/28/2018	Series A-1 Convertible Preferred Stock⁽⁸⁾	7,467	$12.55	I	See footnote⁽²⁾
Warrant to Purchase Series A-1 Stock (right to buy)	⁽⁷⁾	12/18/2018	Series A-1 Convertible Preferred Stock⁽⁸⁾	7,467	$12.55	I	See footnote⁽²⁾
Warrant to Purchase Series A-1 Stock (right to buy)	⁽⁷⁾	04/15/2019	Series A-1 Convertible Preferred Stock⁽⁸⁾	14,634	$12.55	I	See footnote⁽²⁾
Warrant to Purchase Series B Stock (right to buy)	⁽⁷⁾	04/15/2019	Series B Convertible Preferred Stock⁽⁹⁾	9,091	$6.19	I	See footnote⁽²⁾

Explanation of Responses:

1. The Series A-1 Convertible Preferred Stock is convertible into Common Stock on an 18.967-for-one basis into the number of shares of Common Stock as shown in column 3 at any time at the holder's election, and automatically upon the closing of the Issuer's initial public offering, and has no expiration date.

2. The securities are held directly by Cooperative AAC LS U.A. ("Cooperative"). The Reporting Person is a director of Cooperative and disclaims beneficial ownership of all shares held by the foregoing entity except to the extent of his pecuniary interest therein.

3. The Series A-2 Convertible Preferred Stock is convertible into Common Stock on an 18.967-for-one basis into the number of shares of Common Stock as shown in column 3 at any time at the holder's election, and automatically upon the closing of the Issuer's initial public offering, and has no expiration date.

4. The Series B Convertible Preferred Stock is convertible into Common Stock on an 18.967-for-one basis into the number of shares of Common Stock as shown in column 3 at any time at the holder's election, and automatically upon the closing of the Issuer's initial public offering, and has no expiration date.

5. The Series C Convertible Preferred Stock is convertible into Common Stock on an 18.967-for-one basis into the number of shares of Common Stock as shown in column 3 at any time at the holder's election, and automatically upon the closing of the Issuer's initial public offering, and has no expiration date.

6. The Series D Convertible Preferred Stock is convertible into Common Stock on an 18.967-for-one basis into the number of shares of Common Stock as shown in column 3 at any time at the holder's election, and automatically upon the closing of the Issuer's initial public offering, and has no expiration date.

7. This warrant is immediately exercisable.

8. Upon completion of the Issuer's initial public offering, this warrant to purchase shares of Series A-1 Convertible Preferred Stock will automatically convert on an 18.967-for-one basis into a warrant to purchase shares of Common Stock.

9. Upon completion of the Issuer's initial public offering, this warrant to purchase shares of Series B Convertible Preferred Stock will automatically convert on an 18.967-for-one basis into a warrant to purchase shares of Common Stock.

Remarks:

	Linda Bain, Attorney-in-Fact	06/18/2013
	** 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 5 (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).
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