908 Devices (NASDAQ: MASS) SVP details stock options and RSUs

Rhea-AI Filing Summary

908 Devices Inc. executive Kevin J. McCallion, SVP of Products and Production, filed an initial ownership report detailing his equity in the company. He holds several stock option awards, including one covering 42,014 shares, restricted stock units covering 58,602 shares, and 44,925 shares of common stock, all held directly. Footnotes explain multi‑year vesting schedules for the options and RSUs, with key vesting dates beginning February 1, 2024 and extending through February 1, 2027, generally conditioned on his continued service.

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 MA 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)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
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.
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FAQ

What does the Kevin J. McCallion Form 3 filing for 908 Devices (MASS) show?

The Form 3 shows Kevin J. McCallion’s initial equity holdings in 908 Devices. It lists multiple stock option grants, restricted stock units, and 44,925 shares of common stock, all held directly, along with detailed vesting schedules tied to future service dates.

Did Kevin J. McCallion buy or sell 908 Devices (MASS) shares in this Form 3?

The filing does not report any new purchases or sales, only existing holdings. All transaction entries are coded as holdings with unknown transaction codes, indicating this is an initial statement of beneficial ownership rather than a record of recent trading activity.

What stock options does Kevin J. McCallion hold in 908 Devices (MASS)?

He holds several stock option awards, including one with 42,014 underlying shares and others with 37,801 and 40,011 shares. Footnotes describe vesting that began on February 1, 2024, 2025, and 2026, with remaining portions vesting monthly over 24–36 months, subject to continued service.

What restricted stock units (RSUs) are reported for Kevin J. McCallion at 908 Devices (MASS)?

The Form 3 lists multiple RSU awards, including one covering 58,602 shares and others for 48,466 and 15,376 shares. Footnotes state these RSUs vest in one to three annual installments starting February 1, 2026 or 2027 and convert into common stock when vested.

How many 908 Devices (MASS) common shares does Kevin J. McCallion directly own?

The filing reports direct ownership of 44,925 shares of common stock. This figure reflects his beneficial holdings separate from options and RSUs, which may convert into additional shares over time as vesting conditions are satisfied under their respective schedules.

What are the key vesting dates in Kevin J. McCallion’s equity awards at 908 Devices (MASS)?

Key vesting reference dates are February 1, 2024, 2025, 2026, and 2027. Options and RSUs generally vest either 25% or one‑third on these dates, with remaining portions vesting monthly or annually over 24–36 months, conditioned on his continued service with the company.