UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
Under the Securities Exchange Act of 1934
(Amendment No. 5)*
bluebird bio, Inc.
(Name of Issuer)
Common Stock
(Title of Class of Securities)
09609G100
(CUSIP Number)
December 29, 2017
(Date of Event Which Requires Filing of this Statement)
Check the appropriate box to designate the rule pursuant to which this
Schedule is filed:
[X] Rule 13d-1(b)
[ ] Rule 13d-1(c)
[ ] Rule 13d-1(d)
*The remainder of this cover page shall be filled out for a reporting
person's initial filing on this form with respect to the subject class
of securities, and for any subsequent amendment containing information
which would alter the disclosures provided in a prior cover page.
The information required in the remainder of this cover page shall not
be deemed to be "filed" for the purpose of Section 18 of the Securities
Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of
that section of the Act but shall be subject to all other provisions of
the Act (however, see the Notes).
CUSIP: 09609G100 Page 1 of 4
1 NAMES OF REPORTING PERSONS
I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
Capital Research Global Investors **
2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE
INSTRUCTIONS) (a)
(b)
3 SEC USE ONLY
4 CITIZENSHIP OR PLACE OF ORGANIZATION
Delaware
5 SOLE VOTING POWER
6,010,817
6 SHARED VOTING POWER
NUMBER OF
SHARES NONE
BENEFICIALL
Y OWNED BY
7 SOLE DISPOSITIVE POWER
EACH
REPORTING 6,010,817
PERSON
WITH:
8 SHARED DISPOSITIVE POWER
NONE
9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
6,010,817 Beneficial ownership disclaimed pursuant to Rule
13d-4
10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES
(SEE INSTRUCTIONS)
11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
12.2%
12 TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)
IA
** A division of Capital Research and Management Company (CRMC)
CUSIP: 09609G100 Page 2 of 4
SECURITIES AND EXCHANGE COMMISSION
Washington, DC 20549
Schedule 13G
Under the Securities Exchange Act of 1934
Amendment No. 5
Item 1(a) Name of Issuer:
bluebird bio, Inc.
Item 1(b) Address of Issuer's Principal Executive Offices:
150 Second Street
Cambridge, MA 02141
Item 2(a) Name of Person(s) Filing:
Capital Research Global Investors
Item 2(b) Address of Principal Business Office or, if none,
Residence:
333 South Hope Street
Los Angeles, CA 90071
Item 2(c) Citizenship: N/A
Item 2(d) Title of Class of Securities:
Common Stock
Item 2(e) CUSIP Number:
09609G100
Item 3 If this statement is filed pursuant to sections 240.13d-1(b)
or 240.13d-2(b) or (c), check whether the person filing is a:
(e) [X] An investment adviser in accordance with
section 240.13d-1(b)(1)(ii)(E).
Item 4 Ownership
Provide the following information regarding the aggregate
number and percentage of the class of securities of the issuer
identified in Item 1.
(a) Amount beneficially owned:
(b) Percent of class:
(c) Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
(ii) Shared power to vote or to direct the vote:
(iii) Sole power to dispose or to direct the disposition of:
(iv) Shared power to dispose or to direct the disposition of:
See page 2
Capital Research Global Investors divisions of CRMC is deemed
to be the beneficial owner of 6,010,817 shares or 12.2% of the
49,028,297 shares believed to be outstanding.
Item 5 Ownership of Five Percent or Less of a Class. If this
statement is being filed to report the fact that as of the date
hereof the reporting person has ceased to be the beneficial
CUSIP: 09609G100 Page 3 of 4
owner of more than five percent of the class of securities,
check the following: [ ]
Item 6 Ownership of More than Five Percent on Behalf of Another
Person: N/A
Item 7 Identification and Classification of the Subsidiary Which
Acquired the Security Being Reported on By the Parent Holding
Company or Control Person: N/A
Item 8 Identification and Classification of Members of the Group:
N/A
Item 9 Notice of Dissolution of Group: N/A
Item 10 Certification
By signing below, I certify that, to the best of my knowledge
and belief, the securities referred to above were acquired and
are held in the ordinary course of business and were not
acquired and are not held for the purpose of or with the effect
of changing or influencing the control of the issuer of the
securities and were not acquired and are not held in connection
with or as a participant in any transaction having that purpose
or effect.
Signature
After reasonable inquiry and to the best of my knowledge and
belief, I certify that the information set forth in this
statement is true, complete and correct.
Date: February 7, 2018
Signature: /s/ Donald H. Rolfe
Name/Title: Donald H. Rolfe - Senior Vice President
and Senior Counsel, Fund Business
Management Group
Capital Research and Management Company
CUSIP: 09609G100 Page 4 of 4