Director at Keros Therapeutics (KROS) buys 1,000 shares under 10b5-1 plan

Rhea-AI Filing Summary

Keros Therapeutics director Jean Jacques Bienaime bought 1,000 shares of common stock in an open-market transaction at a weighted average price of $10.58 per share. The trades on May 15, 2026 were executed under a Rule 10b5-1 trading plan adopted on December 5, 2025.

Following this purchase, he directly owns 9,450 Keros Therapeutics shares.

Insights

Equity analyst

Pre-planned, modest insider share purchase with limited signaling value.

Director Jean Jacques Bienaime executed an open-market purchase of 1,000 Keros Therapeutics shares at a weighted average of $10.58 on May 15, 2026. After this transaction, he directly holds 9,450 shares of common stock.

The filing notes the trade was made under a Rule 10b5-1 trading plan adopted on December 5, 2025, indicating it was pre-scheduled rather than opportunistic. Such pre-planned, relatively small transactions are generally viewed as routine portfolio management rather than a strong signal about company prospects.

Insider Trade Summary 10b5-1

Net Buyer: 1,000 shares ($10,580)

Net Buy 1 txn

Insider BIENAIME JEAN JACQUES

Role null

Bought 1,000 shs ($11K)

Type	Security	Shares	Price	Value
Purchase	Common Stock	1,000	$10.58	$11K

Holdings After Transaction: Common Stock — 9,450 shares (Direct, null)

Footnotes (1)

1. Shares were purchased pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 5, 2025. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $10.44 to $10.69 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 purchased at each separate price within the range set forth in this footnote.

Key Figures

Shares purchased: 1,000 shares Weighted average price: $10.58 per share Holding after transaction: 9,450 shares +2 more

5 metrics

Shares purchased 1,000 shares Open-market purchase on May 15, 2026

Weighted average price $10.58 per share Price for 1,000-share purchase

Holding after transaction 9,450 shares Direct ownership following purchase

Trade price range $10.44–$10.69 per share Individual trade prices within aggregated purchase

10b5-1 plan adoption date December 5, 2025 Plan governing the reported purchase

Key Terms

Rule 10b5-1 trading plan, weighted average price, open-market purchase

3 terms

Rule 10b5-1 trading plan regulatory

"Shares were purchased pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person"

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

weighted average price financial

"The price reported in Column 4 is a weighted average price."

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

open-market purchase financial

"transaction_action": "open-market purchase""

An open-market purchase is when an investor or a company buys shares on a public stock exchange at the going market price, rather than through a private deal. It matters to investors because these purchases change how many shares are available, can push the stock price up or signal confidence from large buyers, and often affect per-share metrics like earnings—think of it like someone buying lots of apples off a grocery shelf, reducing supply and potentially raising the price.

Form 4 Insider Transactions: What Each Field Means →

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).

X

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

BIENAIME JEAN JACQUES

(Last) (First) (Middle)

C/O KEROS THERAPEUTICS, INC.

1050 WALTHAM STREET, SUITE 302

(Street)

LEXINGTON MASSACHUSETTS 02421

(City) (State) (Zip)

UNITED STATES

(Country)

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)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/15/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

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	05/15/2026		P(1)		1,000	A	$10.58(2)	9,450	D

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

Explanation of Responses:

1. Shares were purchased pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 5, 2025.

2. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $10.44 to $10.69 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 purchased at each separate price within the range set forth in this footnote.

	/s/ Esther Cho, Attorney-in-Fact	05/19/2026
	** 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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

FAQ

What insider transaction did Keros Therapeutics (KROS) report in this filing?

Keros Therapeutics reported that director Jean Jacques Bienaime bought 1,000 shares of common stock. The open-market purchase occurred on May 15, 2026 at a weighted average price of $10.58 per share, increasing his direct ownership stake in the company.

At what price did the Keros Therapeutics director buy shares in this Form 4?

The director’s purchase is reported at a weighted average price of $10.58 per share. Footnotes explain the 1,000 shares were bought in multiple trades, with individual prices ranging from $10.44 to $10.69 inclusive during the same trading session.

How many Keros Therapeutics (KROS) shares does the insider own after this transaction?

Following the reported purchase, director Jean Jacques Bienaime directly owns 9,450 shares of Keros Therapeutics common stock. This total reflects his position immediately after buying 1,000 shares in the open market as disclosed in the Form 4 filing.

Was the Keros Therapeutics insider trade made under a Rule 10b5-1 plan?

Yes. A footnote states the shares were purchased pursuant to a Rule 10b5-1 trading plan adopted on December 5, 2025. Such plans pre-schedule trades, helping insiders systematically diversify while reducing concerns about trading on nonpublic information.

What does the weighted average price mean in this Keros Therapeutics Form 4?

The weighted average price of $10.58 reflects combining several trades into a single figure. Footnotes clarify that the 1,000 shares were bought in multiple transactions between $10.44 and $10.69, and detailed trade-by-trade prices are available upon request from the reporting person.