Statement of Changes in Beneficial Ownership (4)

FORM 4 [ ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES
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Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

1. Name and Address of Reporting Person ^* Knowles Julius	2. Issuer Name and Ticker or Trading Symbol Keros Therapeutics, Inc. [ KROS ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below)
(Last) (First) (Middle) C/O KEROS THERAPEUTICS, INC., 99 HAYDEN AVENUE, SUITE 120, BUILDING E	3. Date of Earliest Transaction (MM/DD/YYYY) 7/1/2021
(Street) LEXINGTON, MA 02421 (City) (State) (Zip)	4. If Amendment, Date Original Filed (MM/DD/YYYY)	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. Trans. Date	2A. Deemed Execution Date, if any	3. Trans. 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)
1.Title of Security (Instr. 3)	2. Trans. Date	2A. Deemed Execution Date, if any	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	7/1/2021		S⁽¹⁾		13268	D	$41.22 ⁽²⁾	530196	I	See footnote ⁽³⁾
Common Stock	7/1/2021		S⁽¹⁾		8650	D	$41.22 ⁽²⁾	355745	I	See footnote ⁽⁴⁾
Common Stock	7/1/2021		S⁽¹⁾		1112	D	$41.89 ⁽⁵⁾	529084	I	See footnote ⁽³⁾
Common Stock	7/1/2021		S⁽¹⁾		728	D	$41.89 ⁽⁵⁾	355017	I	See footnote ⁽⁴⁾
Common Stock	7/1/2021		S⁽¹⁾		46	D	$42.75	529038	I	See footnote ⁽³⁾
Common Stock	7/1/2021		S⁽¹⁾		30	D	$42.75	354987	I	See footnote ⁽⁴⁾
Common Stock	7/2/2021		S⁽¹⁾		8627	D	$41.08 ⁽⁶⁾	520411	I	See footnote ⁽³⁾
Common Stock	7/2/2021		S⁽¹⁾		5626	D	$41.08 ⁽⁶⁾	349361	I	See footnote ⁽⁴⁾
Common Stock	7/2/2021		S⁽¹⁾		5789	D	$41.72 ⁽⁷⁾	514622	I	See footnote ⁽³⁾
Common Stock	7/2/2021		S⁽¹⁾		3776	D	$41.72 ⁽⁷⁾	345585	I	See footnote ⁽⁴⁾

*Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)*
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	4. Trans. 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		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 of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)			11. Nature of Indirect Beneficial Ownership (Instr. 4)

Explanation of Responses:
(1)	The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan.
(2)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $40.74 to $41.73 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (2), (5), (6) and (7).
(3)	The securities are held by Partners Innovation Fund, LLC ("PIF I"). Partners Innovation Fund, LLC ("Partners GP I") is the ultimate general partner of PIF I. The Reporting Person, a member of the board of directors of the Issuer, is a partner of Partners GP I and as a result, may be deemed to share voting and investment power with respect to the shares held by PIF I.
(4)	The securities are held by Partners Innovation Fund II, L.P. ("PIF II"). Partners Innovation Fund II, LLC ("Partners GP II") is the ultimate general partner of PIF II. The Reporting Person, a member of the board of directors of the Issuer, is a partner of Partners GP II and as a result, may be deemed to share voting and investment power with respect to the shares held by PIF II.
(5)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $41.74 to $42.57 inclusive.
(6)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $40.51 to $41.50 inclusive.
(7)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $41.51 to $42.00 inclusive.

Reporting Owners
Reporting Owner Name / Address	Relationships
Reporting Owner Name / Address	Director	10% Owner	Officer	Other
Knowles Julius C/O KEROS THERAPEUTICS, INC. 99 HAYDEN AVENUE, SUITE 120, BUILDING E LEXINGTON, MA 02421	X