SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP 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: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* NELSEN ROBERT (Last) (First) (Middle) C/O UNITY BIOTECHNOLOGY, INC. 3280 BAYSHORE BOULEVARD (Street) BRISBANE CA 94005 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol Unity Biotechnology, Inc. [ UBX ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 06/20/2019
	4. 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 Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock								8,365,764	I	See Footnotes(1)(3)
Common Stock								1,682,417	I	See Footnotes(2)(3)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (Right to Buy)	$9	06/20/2019		A		25,000		(4)	06/19/2029	Common Stock	25,000	$0.00	25,000	D

Explanation of Responses:

1. The shares are directly held by ARCH Venture Fund VII, L.P. ("ARCH VII"). ARCH Venture Partners VII, L.P. (the "GPLP"), as the sole general partner of ARCH VII, may be deemed to beneficially own certain of the shares held by ARCH VII. ARCH Venture Partners VII, LLC ("GPLLC"), as the sole general partner of GPLP, may be deemed to beneficially own the shares held by GPLP. The Reporting Person is a managing director of GPLLC, and as such may be deemed to beneficially own the shares held by ARCH VII. The Reporting Person disclaims beneficial ownership of such shares except to the extent of any pecuniary interest therein.

2. The shares are directly held by ARCH Venture Fund VIII Overage, L.P. ("ARCH Overage"). ARCH Venture Partners VIII, LLC (the "AVP GPLLC"), as the sole general partner of ARCH Overage, may be deemed to beneficially own the shares held by ARCH Overage. The Reporting Person is a managing director of AVP GPLLC, and as such may be deemed to beneficially own the shares held by ARCH Overage. The Reporting Person disclaims beneficial ownership of such shares except to the extent of any pecuniary interest therein.

3. The managing directors of ARCH VII LLC and AVP GPLLC are Keith Crandell, Clinton Bybee and Robert Nelsen, and they may be deemed to beneficially own the shares held by ARCH Fund VII and ARCH Overage. Messrs. Crandell, Bybee and Nelsen disclaim beneficial ownership of such shares, except to the extent of any pecuniary interest therein.

4. The underlying shares subject to the option vest and become exercisable as to 100% of the total number of shares subject to the option on the earlier of (i) the one-year anniversary measured from June 20, 2019 or (ii) the date of the 2020 Annual Meeting of the Issuer's stockholders, assuming continuous service as a Non-Employee Director until such vesting date.

	/s/ Tamara L. Tompkins, Attorney-in-Fact for Robert Nelsen	06/24/2019
	** 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 4 (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).
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