BlackRock Portfolio Management (KROS) discloses 5.7% ownership in Keros Therapeutics

Rhea-AI Filing Summary

BlackRock Portfolio Management LLC reports beneficial ownership of common stock of Keros Therapeutics, Inc. on a Schedule 13G. The firm reports beneficial ownership of 1,122,874 shares of Keros common stock, representing 5.7% of the outstanding class.

BlackRock Portfolio Management LLC, organized in Delaware and based at 50 Hudson Yards, New York, reports sole voting power over 991,089 shares and sole dispositive power over 1,122,874 shares, with no shared voting or dispositive power. Various underlying persons may receive dividends or sale proceeds from these shares, but no single person is reported to hold more than five percent of Keros’ outstanding common stock.

Key Figures

Beneficially owned shares: 1,122,874 shares Percent of class: 5.7% Sole voting power: 991,089 shares +2 more

5 metrics

Beneficially owned shares 1,122,874 shares Common stock of Keros Therapeutics, Inc. beneficially owned by BlackRock Portfolio Management LLC

Percent of class 5.7% Portion of Keros Therapeutics common stock class beneficially owned by BlackRock Portfolio Management LLC

Sole voting power 991,089 shares Shares of Keros Therapeutics common stock over which BlackRock Portfolio Management LLC has sole voting power

Sole dispositive power 1,122,874 shares Shares of Keros Therapeutics common stock over which BlackRock Portfolio Management LLC has sole dispositive power

Form date 07/17/2026 Date signed by Managing Director Spencer Fleming on the Schedule 13G

Key Terms

beneficially owned, Sole Voting Power, Sole Dispositive Power, Schedule 13G, +1 more

5 terms

beneficially owned financial

"this reflects the securities beneficially owned, or deemed to be beneficially owned, by certain business units"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

Sole Voting Power financial

"5 | Sole Voting Power 991,089.00 6 | Shared Voting Power 0.00"

Sole voting power is the exclusive right to cast votes attached to a shareholder’s stock without needing approval from anyone else. Like holding the only remote control for a TV, it lets that holder decide corporate matters such as board members, mergers, and policy changes, making it important to investors because it concentrates control and can strongly influence a company’s strategy and the value of its shares.

Sole Dispositive Power financial

"7 | Sole Dispositive Power 1,122,874.00 8 | Shared Dispositive Power 0.00"

Sole dispositive power is the exclusive legal authority to decide what happens to a security — for example, whether to sell, transfer, or retain shares — without needing anyone else’s permission. Investors care because it signals who truly controls the economic outcome of an investment: like holding the only key to a safe, the holder can realize gains or losses and may trigger regulatory reporting, insider rules, or influence over corporate ownership.

Schedule 13G regulatory

"In accordance with SEC Release No. 34-39538 (January 12, 1998), this reflects the securities beneficially owned"

A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.

Power of Attorney regulatory

"Exhibit 24: Power of Attorney Exhibit 99: Item 7"

A power of attorney is a legal document that allows one person to make decisions and act on behalf of another person, often in financial or legal matters. It’s like giving someone a trusted helper or agent the authority to handle important tasks if you are unable to do so yourself. This matters to investors because it can impact how their assets are managed or transferred if they become unable to oversee their affairs.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 07/17/2026 - 11:34 AM Accepted by SEC EDGAR 07/17/2026 - 11:33 AM Learn about SEC filing dates

FAQ

What percentage of Keros Therapeutics (KROS) does BlackRock Portfolio Management LLC report owning?

BlackRock Portfolio Management LLC reports beneficial ownership of 5.7% of Keros Therapeutics’ common stock. This corresponds to 1,122,874 shares of Keros common stock as disclosed in the Schedule 13G filing.

How many Keros Therapeutics (KROS) shares does BlackRock Portfolio Management LLC have voting power over?

BlackRock Portfolio Management LLC reports sole voting power over 991,089 shares of Keros Therapeutics common stock. It reports no shared voting power with any other party for these securities.

What is the total number of Keros Therapeutics (KROS) shares beneficially owned by BlackRock Portfolio Management LLC?

The filing states that BlackRock Portfolio Management LLC beneficially owns 1,122,874 shares of Keros Therapeutics common stock. This position represents 5.7% of the outstanding class of Keros’ common stock.

Does BlackRock Portfolio Management LLC share dispositive power over Keros Therapeutics (KROS) shares?

No. BlackRock Portfolio Management LLC reports sole dispositive power over 1,122,874 shares of Keros Therapeutics common stock and no shared dispositive power with any other person or entity.

Who ultimately benefits from dividends and sale proceeds of Keros Therapeutics (KROS) shares held by BlackRock Portfolio Management LLC?

The filing explains that various persons have rights to receive dividends or sale proceeds from Keros shares held by BlackRock. However, no single person has an interest exceeding five percent of Keros’ total outstanding common shares.

What type of SEC filing did BlackRock Portfolio Management LLC submit for its Keros Therapeutics (KROS) stake?

BlackRock Portfolio Management LLC submitted a Schedule 13G reporting its beneficial ownership in Keros Therapeutics common stock. This schedule is used by certain shareholders to report holdings of more than five percent of a class of equity securities.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

Keros Therapeutics, Inc.

(Name of Issuer)

Common Stock

(Title of Class of Securities)

492327101

(CUSIP Number)

06/30/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 492327101

1

Names of Reporting Persons

BlackRock Portfolio Management LLC

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 991,089.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 1,122,874.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,122,874.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

5.7 %

12

Type of Reporting Person (See Instructions)

HC

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Keros Therapeutics, Inc.
(b)	Address of issuer's principal executive offices: 1050 WALTHAM STREET, SUITE 302 LEXINGTON MA 02421
Item 2.
(a)	Name of person filing: BlackRock Portfolio Management LLC In accordance with SEC Release No. 34-39538 (January 12, 1998), this Schedule 13G reflects the securities beneficially owned, or deemed to be beneficially owned, by certain business units (collectively, the "Reporting Business Units") of BlackRock, Inc. and its subsidiaries and affiliates. It does not include securities, if any, beneficially owned by other business units whose beneficial ownership of securities are disaggregated from that of the Reporting Business Units in accordance with such release.
(b)	Address or principal business office or, if none, residence: BlackRock Portfolio Management LLC, 50 Hudson Yards New York, NY 10001
(c)	Citizenship: See Item 4 of Cover Page
(d)	Title of class of securities: Common Stock
(e)	CUSIP Number(s): 492327101
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 1122874
(b)	Percent of class: 5.7 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 991089
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 1122874
	(iv) Shared power to dispose or to direct the disposition of: 0
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required. Various persons have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of the common stock of Keros Therapeutics, Inc.. No one person's interest in the common stock of Keros Therapeutics, Inc. is more than five percent of the total outstanding common shares.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	If a parent holding company has filed this schedule, pursuant to Rule 13d-1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary. See Exhibit 99
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

BlackRock Portfolio Management LLC

Signature:	Spencer Fleming
Name/Title:	Managing Director
Date:	07/17/2026

Exhibit Information

Exhibit 24: Power of Attorney Exhibit 99: Item 7