Atlas Venture Associates X Form 3 Initial statement of insider ownership

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

OMB APPROVAL

OMB Number:	3235-0104
Estimated average burden
hours per response:	0.5

1. Name and Address of Reporting Person^*

Atlas Venture Fund X, L.P.

(Last) (First) (Middle)

400 TECHNOLOGY SQUARE, 10TH FLOOR

(Street)

CAMBRIDGE MA 02139

(City) (State) (Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
06/11/2020

3. Issuer Name and Ticker or Trading Symbol
Generation Bio Co. [ GBIO ]

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)
Common Stock	2,590,726	D(1)

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 A Preferred Stock	(2)	(2)	Common Stock	8,521,213	(2)	D(1)
Series C Preferred Stock	(3)	(3)	Common Stock	1,518,819	(3)	D(4)

1. Name and Address of Reporting Person^*

Atlas Venture Fund X, L.P.

(Last) (First) (Middle)

400 TECHNOLOGY SQUARE, 10TH FLOOR

(Street)

CAMBRIDGE MA 02139

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

Atlas Venture Associates X, LLC

(Last) (First) (Middle)

400 TECHNOLOGY SQUARE, 10TH FLOOR

(Street)

CAMBRIDGE MA 02139

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

ATLAS VENTURE ASSOCIATES X, L.P.

(Last) (First) (Middle)

400 TECHNOLOGY SQUARE, 10TH FLOOR

(Street)

CAMBRIDGE MA 02139

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

Atlas Venture Opportunity Fund I, L.P.

(Last) (First) (Middle)

400 TECHNOLOGY SQUARE, 10TH FLOOR

(Street)

CAMBRIDGE MA 02139

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

Atlas Venture Associates Opportunity I, L.P.

(Last) (First) (Middle)

400 TECHNOLOGY SQUARE, 10TH FLOOR

(Street)

CAMBRIDGE MA 02139

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

Atlas Venture Associates Opportunity I, LLC

(Last) (First) (Middle)

400 TECHNOLOGY SQUARE, 10TH FLOOR

(Street)

CAMBRIDGE MA 02139

(City) (State) (Zip)

Explanation of Responses:

1. The shares are held directly by Atlas Venture Fund X, L.P. ("Atlas Venture Fund X"). The general partner of Atlas Venture Fund X is Atlas Venture Associates X, L.P. ("AVA X LP"). Atlas Venture Associates X, LLC ("AVA X LLC") is the general partner of AVA X LP. Each of AVA X LP and AVA X LLC disclaims Section 16 beneficial ownership of the securities held by Atlas Venture Fund X, except to the extent of its pecuniary interest therein, if any.

2. The Series A Preferred Stock automatically converts into the number of shares of Common Stock as shown in Column 3 without payment of further consideration at the holder's election or upon closing of the initial public offering of the Issuer's common stock. The shares have no expiration date.

3. The Series C Preferred Stock automatically converts into the number of shares of Common Stock as shown in Column 3 without payment of further consideration at the holder's election or upon closing of the initial public offering of the Issuer's common stock. The shares have no expiration date.

4. The shares are held directly by Atlas Venture Opportunity Fund I, L.P. ("Atlas Venture Opportunity Fund I"). The general partner of Atlas Venture Opportunity Fund I is Atlas Venture Associates Opportunity I, L.P. ("AVAO I LP"). Atlas Venture Associates Opportunity I, LLC ("AVAO I LLC") is the general partner of AVAO I LP. Each of AVAO I LP and AVAO I LLC disclaims Section 16 beneficial ownership of the securities held by Atlas Venture Opportunity Fund I, except to the extent of its pecuniary interest therein, if any.

Remarks:

	/s/ Atlas Venture Fund X, LP, By: Atlas Venture Associates X, L.P., it's general partner, By: Atlas Venture Associates X, LLC, its general partner, By: Ommer Chohan, Chief Financial Officer, /s/ Ommer Chohan	06/11/2020
	/s/ Atlas Venture Associates X, LP, By: Atlas Venture Associates X, LLC, it's general partner, By: Ommer Chohan, Chief Financial Officer, /s/ Ommer Chohan	06/11/2020
	/s/ Atlas Venture Associates X, LLC, By: Ommer Chohan, Chief Financial Officer, /s/ Ommer Chohan	06/11/2020
	/s/ Atlas Venture Opportunity Fund I, L.P., By: Atlas Venture Associates Opportunity I, L.P., its general partner, By: Atlas Venture Associates Opportunity I, LLC, its general partner, By: Ommer Chohan, Chief Financial Officer, /s/ Ommer Chohan	06/11/2020
	/s/ Atlas Venture Associates Opportunity I, L.P., By: Atlas Venture Associates Opportunity I, LLC, its general partner, By: Ommer Chohan, Chief Financial Officer, /s/ Ommer Chohan	06/11/2020
	/s/ Atlas Venture Associates Opportunity I, LLC, By: Ommer Chohan, Chief Financial Officer, /s/ Ommer Chohan	06/11/2020
	** 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.