908 Devices (MASS) SVP exercises options and sells common shares

Rhea-AI Filing Summary

908 Devices Inc. senior vice president of Products and Production, Kevin J. McCallion, reported small insider transactions in company stock. On March 2, 2026, he exercised a stock option for 7 shares at $1.05 per share and received fully vested, immediately exercisable shares.

He then sold 7 shares of common stock at $7.00 per share in an open-market transaction made under a Rule 10b5-1 trading plan adopted on December 9, 2025. After these transactions, he directly held 26,686 option shares and 44,925 common shares.

Insider Trade Summary

Net Seller: 7 shares ($49)

Net Sell 3 txns

Insider McCallion Kevin J.

Role SVP, Products and Production

Sold 7 shs ($49.00)

Type	Security	Shares	Price	Value
Exercise	Stock Option (right to buy)	7	$0.00	--
Exercise	Common Stock	7	$1.05	$7.35
Sale	Common Stock	7	$7.00	$49.00

Holdings After Transaction: Stock Option (right to buy) — 26,686 shares (Direct); Common Stock — 44,932 shares (Direct)

Footnotes (1)

1. This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 9, 2025. The shares underlying the option are fully vested and immediately exercisable.

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^*

McCallion Kevin J.

(Last) (First) (Middle)

C/O 908 DEVICES INC.

44 3RD AVENUE

(Street)

BURLINGTON MA 01803

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
908 Devices Inc. [ MASS ]

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

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	SVP, Products and Production

3. Date of Earliest Transaction (Month/Day/Year)
03/02/2026

4. If Amendment, Date of Original Filed (Month/Day/Year)
03/04/2026

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

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

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	03/02/2026		M(1)		7	A	$1.05	44,932	D
Common Stock	03/02/2026		S(1)		7	D	$7	44,925	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)	$1.05	03/02/2026		M(1)			7	(2)	08/27/2030	Common Stock	7	$0	26,686	D

Explanation of Responses:

1. This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 9, 2025.

2. The shares underlying the option are fully vested and immediately exercisable.

	/s/ Mark S. Levine, Attorney-in-Fact	03/04/2026
	** 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.

FAQ

What insider transactions did Kevin J. McCallion report for MASS?

Kevin J. McCallion reported exercising a stock option for 7 shares at $1.05 per share and selling 7 shares of common stock at $7.00 per share. Both transactions occurred on March 2, 2026 and were made directly.

Was the 908 Devices (MASS) insider sale under a Rule 10b5-1 plan?

Yes. The sale of 7 shares of common stock at $7.00 per share was made under a Rule 10b5-1 trading plan adopted by Kevin J. McCallion on December 9, 2025, providing a pre-arranged framework for trading.

How many 908 Devices common shares does Kevin J. McCallion hold after this Form 4/A?

Following the reported transactions, Kevin J. McCallion directly held 44,925 shares of 908 Devices common stock. This figure reflects his ownership after exercising 7 option shares and selling 7 shares on March 2, 2026.

What stock options did the 908 Devices executive exercise in this filing?

He exercised a stock option covering 7 shares at an exercise price of $1.05 per share. The filing notes that the shares underlying the option are fully vested and immediately exercisable, and he held 26,686 option shares afterward.

Is the MASS Form 4/A transaction a buy or a sell overall?

The filing shows both an option exercise and a sale, resulting in a net sell of 7 shares. He acquired 7 shares through an option exercise, then sold 7 shares of common stock in an open-market transaction on the same date.