Atrium Therapeutics (RNA) CFO awarded 30,000 RSUs and 60,000 stock options

Rhea-AI Filing Summary

Atrium Therapeutics, Inc. reported that its Chief Financial Officer, Brendan R. Winslow, received equity compensation consisting of restricted stock units and stock options. He was granted 30,000 shares of Common Stock as an award, bringing his direct holdings to 43,601 shares after the transaction.

He was also granted 60,000 stock options to buy Common Stock at an exercise price of $14.30 per share, expiring on April 20, 2036. According to the award terms, 25% of the RSUs vest on March 20, 2027, with the remainder vesting in three yearly installments. For the options, 25% of the underlying shares vest on March 20, 2027, with the remaining shares vesting in 36 substantially equal monthly installments. These are compensation-related grants, not open-market purchases.

Insider Trade Summary

2 transactions reported

Mixed 2 txns

Insider Winslow Brendan R.

Role Chief Financial Officer

Type	Security	Shares	Price	Value
Grant/Award	Stock Option (Right to Buy)	60,000	$0.00	--
Grant/Award	Common Stock	30,000	$0.00	--

Holdings After Transaction: Stock Option (Right to Buy) — 60,000 shares (Direct, null); Common Stock — 43,601 shares (Direct, null)

Footnotes (1)

1. Represents an award of restricted stock units ("RSUs"). Each RSU represents a contingent right to receive one share of the Issuer's common stock. Twenty-five percent (25%) of the RSUs shall vest on March 20, 2027, with the remaining RSUs vesting in three (3) substantially equal yearly installments each year thereafter, subject to the Reporting Person's continuous service to the Issuer on each such vesting date. Twenty-five percent (25%) of the shares underlying this option shall vest and become exercisable on March 20, 2027, with the remaining shares vesting in thirty-six (36) substantially equal monthly installments each month thereafter, subject to the Reporting Person's continuous service to the Issuer on each such vesting date.

Key Figures

RSU grant: 30,000 shares Options granted: 60,000 options Option exercise price: $14.30 per share +4 more

7 metrics

RSU grant 30,000 shares Restricted stock units awarded to CFO on April 20, 2026

Options granted 60,000 options Stock Option (Right to Buy) granted on April 20, 2026

Option exercise price $14.30 per share Exercise price for 60,000 stock options

Shares held after grant 43,601 shares Total Common Stock directly owned by CFO following award

RSU initial vesting date March 20, 2027 25% of RSUs vest on this date

Option initial vesting date March 20, 2027 25% of option shares vest and become exercisable

Option expiration April 20, 2036 Expiration date of 60,000 stock options

Key Terms

restricted stock units ("RSUs"), Stock Option (Right to Buy), vesting, exercise price, +1 more

5 terms

restricted stock units ("RSUs") financial

"Represents an award of restricted stock units ("RSUs"). Each RSU represents a contingent right"

Restricted stock units (RSUs) are a company promise to give an employee shares of stock (or cash equivalent) in the future, but only after certain conditions—usually staying with the company for a set time or hitting performance goals—are met. Investors watch RSUs because when they vest they increase the number of shares outstanding and can lead insiders to sell shares, affecting share price, company dilution and the true cost of employee pay.

Stock Option (Right to Buy) financial

"Stock Option (Right to Buy) with 60,000.0000 underlying shares of Common Stock"

vesting financial

"Twenty-five percent (25%) of the RSUs shall vest on March 20, 2027, with the remaining RSUs vesting"

Vesting is the process by which you earn full ownership of something, like company stock or a retirement benefit, over time. It’s like earning the right to keep a gift piece by piece the longer you stay with a company, making sure employees stay committed before they receive all the benefits.

exercise price financial

"conversion_or_exercise_price": "14.3000" for the Stock Option (Right to Buy)"

The exercise price is the fixed amount at which you can buy or sell an asset, like a stock, when using an options contract. It matters because it helps determine whether exercising the option will be profitable or not, depending on the current market price. Think of it as the set price you agree on today to buy or sell later.

expiration date financial

"expiration_date": "2036-04-20T00:00:00.000Z" for the stock option grant"

The expiration date is the deadline after which a financial contract, such as an option or a futures agreement, is no longer valid or can be exercised. It matters to investors because it determines the timeframe during which they can take action or benefit from the contract, similar to how a coupon or a food item has a limited period of usefulness. Once the expiration date passes, the contract loses its value or ability to be used.

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).

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^*

Winslow Brendan R.

(Last) (First) (Middle)

C/O ATRIUM THERAPEUTICS, INC.

10578 SCIENCE CENTER DRIVE, SUITE 125

(Street)

SAN DIEGO CALIFORNIA 92121

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Atrium Therapeutics, Inc. [ RNA ]

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

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Financial Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/20/2026

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	04/20/2026		A		30,000(1)	A	$0	43,601	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
Stock Option (Right to Buy)	$14.3	04/20/2026		A		60,000		(2)	04/20/2036	Common Stock	60,000	$0	60,000	D

Explanation of Responses:

1. Represents an award of restricted stock units ("RSUs"). Each RSU represents a contingent right to receive one share of the Issuer's common stock. Twenty-five percent (25%) of the RSUs shall vest on March 20, 2027, with the remaining RSUs vesting in three (3) substantially equal yearly installments each year thereafter, subject to the Reporting Person's continuous service to the Issuer on each such vesting date.

2. Twenty-five percent (25%) of the shares underlying this option shall vest and become exercisable on March 20, 2027, with the remaining shares vesting in thirty-six (36) substantially equal monthly installments each month thereafter, subject to the Reporting Person's continuous service to the Issuer on each such vesting date.

	/s/ Brendan Winslow	04/22/2026
	** 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 equity awards did Atrium Therapeutics (RNA) grant to its CFO Brendan Winslow?

Atrium Therapeutics granted CFO Brendan Winslow 30,000 shares of Common Stock and 60,000 stock options as equity compensation. The stock options allow him to buy shares at $14.30 each, subject to multi-year vesting schedules tied to continued service.

How many Atrium Therapeutics (RNA) shares does the CFO hold after this Form 4?

After these grants, CFO Brendan Winslow directly holds 43,601 shares of Atrium Therapeutics Common Stock. This figure reflects his ownership following the 30,000-share restricted stock award reported in the filing, excluding the 60,000 unexercised stock options granted.

What is the vesting schedule for the 30,000 RSUs granted by Atrium Therapeutics (RNA)?

The 30,000 RSUs vest over four years. Twenty-five percent vest on March 20, 2027, and the remaining RSUs vest in three substantially equal yearly installments thereafter, contingent on Brendan Winslow’s continuous service with Atrium Therapeutics on each vesting date.

What are the key terms of the 60,000 stock options granted by Atrium Therapeutics (RNA)?

The 60,000 stock options have a $14.30 exercise price and expire on April 20, 2036. Twenty-five percent of the underlying shares vest on March 20, 2027, with the balance vesting in 36 substantially equal monthly installments, subject to continued service.

Does this Atrium Therapeutics (RNA) Form 4 show insider buying or market selling?

The Form 4 shows compensation-related equity grants, not market trades. Brendan Winslow received 30,000 shares and 60,000 options as awards, with no open-market purchases or sales reported. The transactions reflect non-cash grants tied to his executive role.