SEC FORM 3

SEC FORM 3 SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person^*

McCallion Kevin J.

(Last)

(First)

(Middle)

C/O 908 DEVICES INC.

44 3RD AVENUE

(Street)

BURLINGTON

01803

(City)

(State)

(Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
02/26/2026

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

4. 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

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

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 Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	44,925	D

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
1. Title of Derivative Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
Stock Option (right to buy)	⁽¹⁾	08/27/2030	Common Stock	26,693	$1.05	D
Stock Option (right to buy)	⁽¹⁾	03/01/2032	Common Stock	27,917	$16.66	D
Stock Option (right to buy)	⁽²⁾	02/28/2033	Common Stock	37,801	$8.83	D
Stock Option (right to buy)	⁽³⁾	02/28/2034	Common Stock	42,014	$7.35	D
Stock Option (right to buy)	⁽⁴⁾	03/02/2035	Common Stock	40,011	$1.98	D
Stock Option (right to buy)	⁽⁵⁾	02/01/2036	Common Stock	21,187	$6.19	D
Restricted Stock Units	⁽⁶⁾	⁽⁶⁾	Common Stock	6,229	⁽⁷⁾	D
Restricted Stock Units	⁽⁸⁾	⁽⁸⁾	Common Stock	15,376	⁽⁷⁾	D
Restricted Stock Units	⁽⁸⁾	⁽⁸⁾	Common Stock	58,602	⁽⁷⁾	D
Restricted Stock Units	⁽⁹⁾	⁽⁹⁾	Common Stock	48,466	⁽⁷⁾	D

Explanation of Responses:

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

2. Twenty-five percent of the shares underlying the option became vested and exercisable on February 1, 2024, and the remaining 75% of the shares underlying the option became or will become vested and exercisable in substantially equal monthly installments over the 36 months following February 1, 2024, subject to the reporting person's continued service through the applicable vesting date.

3. Twenty-five percent of the shares underlying the option became vested and exercisable on February 1, 2025, and the remaining 75% of the shares underlying the option became or will become vested and exercisable in substantially equal monthly installments over the 36 months following February 1, 2025, subject to the reporting person's continued service through the applicable vesting date.

4. One-third of the shares underlying the option became vested and exercisable on February 1, 2026, and the remaining two-thirds of the shares underlying the option became or will become vested and exercisable in substantially equal monthly installments over the 24 months following February 1, 2026, subject to the reporting person's continued service through the applicable vesting date.

5. One-third of the shares underlying the option become vested and exercisable on February 1, 2027, and the remaining two-thirds of the shares underlying the option become vested and exercisable in substantially equal monthly installments over the 24 months following February 1, 2027, subject to the reporting person's continued service through the applicable vesting date.

6. These restricted stock units ("RSUs") vest on February 1, 2027, subject to the reporting person's continued service through the applicable vesting date. The RSUs have no expiration date.

7. Each RSU represents a contingent right to receive one share of Common Stock, par value $0.001, when vested.

8. These RSUs vest in two substantially equal annual installments at the two anniversary dates following February 1, 2026, subject to the reporting person's continued service through the applicable vesting date. The RSUs have no expiration date.

9. These RSUs vest in three substantially equal annual installments at the three anniversary dates following February 1, 2026, subject to the reporting person's continued service through the applicable vesting date. The RSUs have no expiration date.

	/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 5 (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.

New insider Mccallion Kevin J. claimed ownership of 44,925 shares (SEC Form 3)