SC 13G 1 fp0086874-11_sc13g.htm

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

(Rule 13d-102)

INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT

TO RULE 13d-1(b), (c), AND (d) AND AMENDMENTS THERETO FILED

PURSUANT TO RULE 13d-2(b)

(AMENDMENT NO. 0)*

bluebird bio, Inc.

(Name of Issuer)

Common Stock, $0.01 par value per share

(Title of Class of Securities)

09609G100

(CUSIP Number)

December 31, 2023

(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 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 NO. 09609G100

13G

Page 2 of 5 Pages

1	NAMES OF REPORTING PERSONS S.S. OR I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS Granahan Investment Management LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP			(a) [ ] (b) [ ]
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION State of Massachusetts
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH		5	SOLE VOTING POWER 6,741,868
		6	SHARED VOTING POWER None
		7	SOLE DISPOSITIVE POWER 8,077,697
		8	SHARED DISPOSITIVE POWER None
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 8,077,697
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW 9 EXCLUDES CERTAIN SHARES			[ ]
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 7.38%
12	TYPE OF REPORTING PERSON IA

CUSIP NO. 09609G100

13G

Page 3 of 5 Pages

Item 1.

(a)

Name of Issuer:

bluebird bio, Inc.

(b)

Address of Issuer’s Principal Executive Offices:

455 Grand Union Boulevard

Somerville, Massachusetts 02145

Item 2.

(a)

Name of Person Filing:

Granahan Investment Management LLC

(b)

Address of Principal Business Office or, if None, Residence:

Wyman Street, Suite 460

Waltham, MA 02451

(c)

Citizenship:

State of Massachusetts

(d)

Title of Class of Securities:

Common Stock, $0.01 par value per share

(e)

CUSIP Number:

09609G100

Item 3.

If This Statement is Filed Pursuant to Rule 13d-1(b), or 13d-2(b) or (c), Check Whether the Person Filing is a:

(a) [ ]

Broker or dealer registered under Section 15 of the Exchange Act.

(b) [ ]

Bank as defined in Section 3(a)(6) of the Exchange Act.

Insurance company as defined in Section 3(a)(19) of the Exchange Act.

(d) [ ]

Investment company registered under Section 8 of the Investment Company Act.

(e [ X]

An investment adviser in accordance with Rule 13d-1(b)(1)(ii)(E);

(f) [ ]

An employee benefit plan or endowment fund in accordance with Rule 13d-1(b)(1)(ii)(F);

(g) [ ]

A parent holding company or control person in accordance with Rule 13d-1(b)(1)(ii)(G);

(h) [ ]

A savings association as defined in Section 3(b) of the Federal Deposit Insurance Act;

(i) [ ]

A church plan that is excluded from the definition of an investment company under Section 3(c)(14) of the Investment Company Act;

(j) [ ]

Group, in accordance with Rule 13d-1(b)(1)(ii)(J).

CUSIP NO. 09609G100

13G

Page 4 of 5 Pages

Item 4.

Ownership.

(a)	Amount beneficially owned:		8,077,697
(b)	Percent of class:		7.38%
(c)	Number of shares as to which the person has:
	(i)	Sole power to vote or to direct the vote:	6,741,868
	(ii)	Shared power to vote or to direct the vote:	0
	(iii)	Sole power to dispose or to direct the disposition of:	8,077,697
	(iv)	Shared power to dispose or to direct the disposition of:	0

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 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.

All of the Shares set forth in Item 4 are owned by various investment advisory clients of Granahan Investment Management LLC, which is deemed to be a beneficial owner of those shares pursuant to Rule 13d-3 under the Securities Exchange Act of 1934, due to its discretionary power to make investment decisions over such shares and/or its ability to vote such shares.

Item 7.

Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.

Not applicable

Item 8.

Identification and Classification of Members of the Group.

Not applicable

Item 9.

Notice of Dissolution of Group.

Not applicable

CUSIP NO. 09609G100

13G

Page 5 of 5 Pages

Item 10.

Certification.

By signing below the undersigned certifies that, to the best of my knowledge and belief, the securities referred to above were acquired and 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.

	Granahan Investment Management LLC

	By:	/s/Brian Granahan
	Name:	Brian Granahan
	Title:	Chief Compliance Officer

	Date:	February 14, 2024

SEC Form SC 13G filed by bluebird bio Inc.