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* 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) 06/20/2018	3. Issuer Name and Ticker or Trading Symbol AVROBIO, Inc. [ AVRO ]
		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 Seed Preferred Stock	(1)	(1)	Common Stock	3,333,333	(1)	I	See Footnote(2)
Series A Preferred Stock	(1)	(1)	Common Stock	12,580,199	(1)	I	See Footnote(2)
Series B Preferred Stock	(1)	(1)	Common Stock	3,740,239	(1)	I	See Footnote(2)

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, 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)

Explanation of Responses:

1. All series of Convertible Preferred Stock shall automatically convert on a 4.132-for-1 basis into shares of the Issuer's Common Stock immediately prior to the closing of the Issuer's initial public offering and have no expiration date

2. 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.

Remarks:

	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	06/20/2018
	Atlas Venture Associates X, LP, By: Atlas Venture Associates X, LLC, it's general partner, By: Ommer Chohan, Chief Financial Officer, /s/ Ommer Chohan	06/20/2018
	Atlas Venture Associates X, LLC, By: Ommer Chohan, Chief Financial Officer, /s/ Ommer Chohan	06/20/2018
	** 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).
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