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* Arch Venture Fund VII LP (Last) (First) (Middle) 8725 WEST HIGGINS ROAD SUITE 290 (Street) CHICAGO IL 60631 (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) Director X 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) Form filed by One Reporting Person X 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)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Series C Convertible Preferred Stock	(1)	(1)	Common Stock	1,052,946	(1)	D(2)(3)
Series D Convertible Preferred Stock	(4)	(4)	Common Stock	740,642	(4)	D(2)(3)

1. Name and Address of Reporting Person* Arch Venture Fund VII LP (Last) (First) (Middle) 8725 WEST HIGGINS ROAD SUITE 290 (Street) CHICAGO IL 60631 (City) (State) (Zip)

1. Name and Address of Reporting Person* ARCH Venture Partners VII, L.P. (Last) (First) (Middle) 8725 WEST HIGGINS ROAD SUITE 290 (Street) CHICAGO IL 60631 (City) (State) (Zip)

1. Name and Address of Reporting Person* ARCH Venture Partners VII, LLC (Last) (First) (Middle) 8725 WEST HIGGINS ROAD SUITE 290 (Street) CHICAGO IL 60631 (City) (State) (Zip)

1. Name and Address of Reporting Person* CRANDELL KEITH (Last) (First) (Middle) 8725 WEST HIGGINS ROAD SUITE 290 (Street) CHICAGO IL 60631 (City) (State) (Zip)

1. Name and Address of Reporting Person* BYBEE CLINTON (Last) (First) (Middle) 8725 WEST HIGGINS ROAD SUITE 290 (Street) CHICAGO IL 60631 (City) (State) (Zip)

1. Name and Address of Reporting Person* NELSEN ROBERT (Last) (First) (Middle) 8725 WEST HIGGINS ROAD SUITE 290 (Street) CHICAGO IL 60631 (City) (State) (Zip)

Explanation of Responses:

1. 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.

2. Beneficial ownership consists of: 1,793,588 shares of Common Stock issuable upon conversion of shares of Series C Convertible Preferred Stock and Series D Convertible Preferred Stock held by ARCH Venture Fund VII, L.P. ("ARCH Fund VII").

3. The sole general partner of ARCH Fund VII is ARCH Venture Partners VII, L.P. ("ARCH Partners VII"), which may be deemed to be the beneficial owner of the shares held by ARCH Fund VII. The sole general partner of ARCH Partners VII is ARCH Venture Partners VII, LLC ("ARCH VII LLC"), which may be deemed to be the beneficial owner of the shares held by ARCH Fund VII. ARCH Partners VII and ARCH VII LLC disclaim beneficial ownership of such shares, except to the extent of any pecuniary interest therein. The managing directors of ARCH VII LLC are Keith Crandell, Clinton Bybee and Robert Nelsen, and they may be deemed to beneficially own the shares held by ARCH Fund VII. Messrs. Crandell, Bybee and Nelsen disclaim beneficial ownership of such shares, except to the extent of any pecuniary interest therein.

4. 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.

Remarks:

	By: /s/ Mark McDonnell, as Attorney-in-Fact for Keith Crandell, Managing Director of the general partner of the general partner of ARCH Fund VII	06/18/2013
	By: /s/ Mark McDonnell, as Attorney-in-Fact for Keith Crandell, Managing Director of the general partner of ARCH Partners VII	06/18/2013
	By: /s/ Mark McDonnell, as Attorney-in-Fact for Keith Crandell, Managing Director of ARCH VII LLC	06/18/2013
	By: /s/ Mark McDonnell, as Attorney-in-Fact for Keith Crandell	06/18/2013
	By: /s/ Mark McDonnell, as Attorney-in-Fact for Clinton Bybee	06/18/2013
	By: /s/ Mark McDonnell, as Attorney-in-Fact for Robert Nelsen	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).
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.

POWER OF ATTORNEY

KNOW ALL MEN BY THESE PRESENTS, that each person whose signature appears below
hereby constitutes and appoints Mark McDonnell his true and lawful
attorney-in-fact, with full power of substitution, to sign any and all
instruments, certificates and documents that may be necessary, desirable or
appropriate to be executed on behalf of himself as an individual or in his
capacity as a direct or indirect general partner, director, officer or manager
of any partnership, corporation or limited liability company, pursuant to
section 13 or 16 of the Securities Exchange Act of 1934, as amended (the
"Exchange Act"), and any and all regulations promulgated thereunder, and to file
the same, with all exhibits thereto, and any other documents in connection
therewith, with the Securities and Exchange Commission, and with any other
entity when and if such is mandated by the Exchange Act or by the Financial
Industry Regulatory Authority, granting unto said attorney-in-fact full power
and authority to do and perform each and every act and thing necessary,
desirable or appropriate, fully to all intents and purposes as he might or could
do in person, thereby ratifying and confirming all that said attorney-in-fact,
or his substitutes, may lawfully do or cause to be done by virtue hereof.  This
power of attorney is perpetual and shall survive the death, incapacity,
dissolution or termination of the undersigned.

IN WITNESS WHEREOF, this Power of Attorney has been signed as of the 7th day of
May, 2013.

				ARCH VENTURE FUND VII, L.P.

			        By: ARCH Venture Partners VII, L.P.
				its General Partner

				    By: ARCH Venture Partners VII, LLC
				    its General Partner

				        By: /s/ Keith Crandell
	                                Managing Director



				ARCH VENTURE PARTNERS VII, L.P.

				By:	ARCH Venture Partners VII, LLC
					its General Partner

					By:  /s/ Keith Crandell
					     Managing Director




				ARCH VENTURE PARTNERS VII, LLC

				By:  /s/ Keith Crandell
				     Managing Director


				 /s/ Keith Crandell
				 Keith Crandell

				 /s/ Robert Nelsen
				 Robert Nelsen

				 /s/ Clint Bybee
                           Clinton Bybee