Planned Monte Rosa (GLUE) CEO share sale under Rule 10b5-1

Rhea-AI Filing Summary

Monte Rosa Therapeutics President & CEO Markus Warmuth reported an open-market sale of 5,467 shares of common stock. The shares were sold at a weighted average price of $18.922 per share, in multiple trades between $18.67 and $19.38.

After the transaction, Warmuth directly holds 600,004 shares of Monte Rosa Therapeutics. The sale was carried out under a pre-arranged Rule 10b5-1 trading plan adopted on May 14, 2025, indicating the transaction timing was set in advance rather than being purely discretionary.

Insider Trade Summary 10b5-1

Net Seller: 5,467 shares ($103,447)

Net Sell 1 txn

Insider Warmuth Markus

Role President & CEO

Sold 5,467 shs ($103K)

Type	Security	Shares	Price	Value
Sale	Common Stock	5,467	$18.922	$103K

Holdings After Transaction: Common Stock — 600,004 shares (Direct, null)

Footnotes (1)

1. These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted on May 14, 2025. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $18.67 to $19.38, 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 range.

Key Figures

Shares sold: 5,467 shares Weighted average sale price: $18.922 per share Shares held after transaction: 600,004 shares

3 metrics

Shares sold 5,467 shares Open-market sale of common stock

Weighted average sale price $18.922 per share Common stock sale on transaction date

Shares held after transaction 600,004 shares Direct ownership following Form 4 sale

Key Terms

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

3 terms

Rule 10b5-1 trading plan regulatory

"These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted on May 14, 2025."

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 sale financial

"transaction_action": "open-market sale""

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

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^*

Warmuth Markus

(Last) (First) (Middle)

MONTE ROSA THERAPEUTICS, INC.

321 HARRISON AVENUE, SUITE 900

(Street)

BOSTON MASSACHUSETTS 02118

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Monte Rosa Therapeutics, Inc. [ GLUE ]

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

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	President & CEO

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/01/2026

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	05/01/2026		S(1)		5,467	D	$18.922(2)	600,004	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. These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted on May 14, 2025.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $18.67 to $19.38, 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 range.

	/s/ Markus Warmuth	05/05/2026
	** 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 did Monte Rosa Therapeutics (GLUE) disclose in this Form 4 filing?

Monte Rosa Therapeutics reported that President & CEO Markus Warmuth executed an open-market sale of 5,467 common shares at a weighted average price of $18.922. After this transaction, he directly holds 600,004 shares, reflecting a relatively small, disclosed adjustment to his ownership.

How many Monte Rosa Therapeutics (GLUE) shares did the CEO sell and at what price?

CEO Markus Warmuth sold 5,467 shares of Monte Rosa Therapeutics common stock. The filing states a weighted average sale price of $18.922 per share, with individual trade prices ranging from $18.67 to $19.38, across multiple open-market transactions on the same reporting date.

How many Monte Rosa Therapeutics (GLUE) shares does the CEO hold after this transaction?

Following the reported sale, Markus Warmuth directly holds 600,004 shares of Monte Rosa Therapeutics common stock. This post-transaction ownership figure comes directly from the Form 4 and shows he retains a substantial continuing equity stake in the company after the disclosed sale.

Was the Monte Rosa Therapeutics (GLUE) CEO sale under a Rule 10b5-1 trading plan?

Yes. A footnote explains the transactions were effected under a Rule 10b5-1 trading plan adopted on May 14, 2025. Such plans pre-arrange trade timing and quantities, signaling that these sales followed a predetermined schedule rather than opportunistic market timing.

What type of transaction did the Monte Rosa Therapeutics (GLUE) Form 4 report?

The Form 4 reports an open-market sale of common stock, coded as “S” for sale. It is classified as a non-derivative transaction, meaning it involved outright common shares rather than options or other derivative securities, and did not include any option exercises or conversions.