Booth Bruce Form 3 Magenta Therapeutics / Bruce Booth ownership change

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^*

Booth Bruce

(Last) (First) (Middle)

C/O MAGENTA THERAPEUTICS, INC

50 HAMPSHIRE STREET

(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
Magenta Therapeutics, Inc. [ MGTA ]

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director	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)

X	Form filed by One Reporting Person
	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	96,749	I	See Footnote(3)

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	(1)	(1)	Common Stock	4,667,797	(1)	I	See Footnote(3)
Series B Preferred Stock	(2)	(2)	Common Stock	79,079	(2)	I	See Footnote(3)

Explanation of Responses:

1. Each share of Series A Preferred Stock is convertible into shares of the Issuer's common stock, $0.001 par value per share ("Common Stock") on a 2.58398:1 basis. Upon the closing of the Issuer's initial public offering, all shares of Series A Preferred Stock will convert into shares of Common Stock of the Issuer. The Series A Preferred Stock has no expiration date.

2. Each share of Series B Preferred Stock is convertible into shares of the Issuer's Common Stock on a 2.58398:1 basis. Upon the closing of the Issuer's initial public offering, all shares of Series B Preferred Stock will convert into shares of Common Stock of the Issuer. The Series B Preferred Stock has no expiration date.

3. 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. Dr. Booth is a member of AVA X LLC and disclaims beneficial ownership of such securities held by Atlas Venture Fund X, except to the extent of his pecuniary interest therein, if any.

Remarks:

Exhibit 24.1: Power of Attorney

	/s/ Ommer Chohan, Attorney-in-Fact for Bruce Booth	06/20/2018
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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