908 Devices (MASS) SVP John Kenneweg details options, RSUs and shares

Rhea-AI Filing Summary

908 Devices Inc. executive John Kenneweg, SVP of Sales & Product Marketing, filed an initial Form 3 detailing his equity holdings in the company. The filing shows multiple stock option awards and restricted stock units, along with 57,784 shares of Common Stock held directly as of February 26, 2026.

Footnotes describe how various option grants and RSUs vest over time, with portions having already vested and remaining amounts vesting in monthly or annual installments through 2027, subject to his continued service. All entries are reported as holdings, with no explicit purchases or sales indicated in this filing.

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^*

Kenneweg John

(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, Sales & Product Marketing

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	57,784	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)	12/02/2026	Common Stock	27,656	$0.96	D
Stock Option (right to buy)	(1)	01/21/2029	Common Stock	61,459	$1.58	D
Stock Option (right to buy)	(1)	09/14/2030	Common Stock	36,875	$3.24	D
Stock Option (right to buy)	(1)	12/01/2031	Common Stock	8,702	$24	D
Stock Option (right to buy)	(1)	03/01/2032	Common Stock	13,460	$16.66	D
Stock Option (right to buy)	(2)	02/28/2033	Common Stock	46,049	$8.83	D
Stock Option (right to buy)	(3)	02/28/2034	Common Stock	41,822	$7.35	D
Stock Option (right to buy)	(4)	03/02/2035	Common Stock	39,828	$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	7,588	(7)	D
Restricted Stock Units	(8)	(8)	Common Stock	15,306	(7)	D
Restricted Stock Units	(8)	(8)	Common Stock	58,333	(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	03/06/2026
	** 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.

FAQ

What does the 908 Devices (MASS) Form 3 for John Kenneweg report?

The Form 3 reports John Kenneweg’s initial beneficial ownership in 908 Devices, including stock options, restricted stock units, and 57,784 directly held common shares as of February 26, 2026, plus detailed vesting schedules extending through 2027 tied to his continued service.

How many 908 Devices (MASS) common shares does John Kenneweg hold directly?

John Kenneweg is reported as directly holding 57,784 shares of 908 Devices common stock as of February 26, 2026. This figure reflects his beneficial ownership of issued shares, separate from his stock options and restricted stock unit awards disclosed in the same Form 3.

What equity awards are disclosed for John Kenneweg in 908 Devices (MASS) Form 3?

The Form 3 discloses multiple stock option awards and several restricted stock unit grants for John Kenneweg. These awards vest over time, with portions already vested and remaining tranches scheduled to vest in monthly or annual installments through 2027, assuming he continues in service.

How do John Kenneweg’s stock options at 908 Devices (MASS) vest?

The stock option footnotes state that some grants vested 25% or one-third on specific February 1 dates, with remaining shares vesting in substantially equal monthly installments over 24 or 36 months, extending through 2026 and 2027, conditioned on his continued service with 908 Devices.

What are the vesting terms for John Kenneweg’s RSUs at 908 Devices (MASS)?

The RSU footnotes explain that some restricted stock units vest fully on February 1, 2027, while others vest in two or three substantially equal annual installments following February 1, 2026. Each RSU converts into one share of common stock upon vesting and has no expiration date.

Does the 908 Devices (MASS) Form 3 show insider stock purchases or sales?

The Form 3 lists John Kenneweg’s holdings in stock options, restricted stock units, and common stock, but does not report explicit purchases or sales. All transaction entries are characterized as holdings, reflecting his beneficial ownership position rather than new buy or sell activity.