[Form 3] 908 Devices Inc. Initial Statement of Beneficial Ownership

Rhea-AI Filing Summary

Christopher D. Brown filed an initial Statement of Beneficial Ownership (Form 3) for 908 Devices (MASS) following his appointment as Director. The filing reveals significant equity holdings as of June 13, 2025:

• Direct Common Stock ownership: 962,122 shares
• Stock Options: Total of 320,404 shares at various exercise prices ranging from $1.75 to $16.66, with different vesting schedules
• Restricted Stock Units (RSUs): 52,837 units vesting over four annual installments from 2022-2024

The stock options include both fully vested options and those with future vesting schedules through 2025. RSUs represent contingent rights to receive common stock upon vesting, with no expiration date. This substantial equity position aligns the director's interests with shareholders and indicates a long-term commitment to the company.

Positive

• Director Christopher D. Brown holds significant direct ownership of 962,122 shares of common stock, demonstrating substantial alignment with shareholder interests

Negative

• None.

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^*

Brown Christopher D.

(Last) (First) (Middle)

C/O 908 DEVICES INC.

645 SUMMER STREET

(Street)

BOSTON MA 02210

(City) (State) (Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
06/13/2025

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

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

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

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	962,122	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 (option to buy)	(1)	06/22/2027	Common Stock	114,318	$1.75	D
Stock Option (option to buy)	(1)	09/21/2030	Common Stock	67,604	$3.24	D
Stock Option (option to buy)	(2)	03/01/2032	Common Stock	33,400	$16.66	D
Stock Option (option to buy)	(3)	02/28/2033	Common Stock	45,018	$8.83	D
Stock Option (option to buy)	(4)	02/28/2034	Common Stock	60,064	$7.35	D
Restricted Stock Units	(6)	(6)	Common Stock	5,027	(5)	D
Restricted Stock Units	(7)	(7)	Common Stock	14,836	(5)	D
Restricted Stock Units	(8)	(8)	Common Stock	32,974	(5)	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 become vested and exercisable on February 1, 2023, and the remaining 75% of the shares underlying the option become vested and exercisable in substantially equal monthly installments over the 36 months following February 1, 2023, subject to the reporting person's continued service through the applicable vesting date.

3. Twenty-five percent of the shares underlying the option become vested and exercisable on February 1, 2024, and the remaining 75% of the shares underlying the option 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.

4. Twenty-five percent of the shares underlying the option become vested and exercisable on February 1, 2025, and the remaining 75% of the shares underlying the option 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.

5. Each Restricted Stock Unit ("RSU") represents a contingent right to receive one share of Common Stock, par value $0.001, when vested. This transaction represents the settlement of RSUs in shares of Common Stock on their scheduled vesting date.

6. These RSUs vest in four substantially equal annual installments at the four anniversary dates following February 1, 2022, subject to the reporting person's continued service through the applicable vesting date. The RSUs have no expiration date.

7. These RSUs vest in four substantially equal annual installments at the four anniversary dates following February 1, 2023, subject to the reporting person's continued service through the applicable vesting date. The RSUs have no expiration date.

8. These RSUs vest in four substantially equal annual installments at the four anniversary dates following February 1, 2024, subject to the reporting person's continued service through the applicable vesting date. The RSUs have no expiration date.

Remarks:

	/s/ Michael S. Turner, as Attorney-in-Fact	06/18/2025
	** 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

How many shares of MASS stock does Christopher Brown directly own?

According to the Form 3 filing, Christopher Brown directly owns 962,122 shares of MASS common stock.

What stock options does Christopher Brown hold in MASS?

Christopher Brown holds several stock options in MASS: 114,318 shares at $1.75 (expires 6/22/2027), 67,604 shares at $3.24 (expires 9/21/2030), 33,400 shares at $16.66 (expires 3/1/2032), 45,018 shares at $8.83 (expires 2/28/2033), and 60,064 shares at $7.35 (expires 2/28/2034).

How many Restricted Stock Units (RSUs) does Christopher Brown have in MASS?

Christopher Brown holds three RSU grants totaling 52,837 units: 5,027 RSUs vesting from February 2022, 14,836 RSUs vesting from February 2023, and 32,974 RSUs vesting from February 2024. Each RSU represents one share of common stock upon vesting.

What is Christopher Brown's role at MASS?

According to the Form 3 filing, Christopher Brown serves as a Director of 908 Devices Inc. (MASS).

What is the vesting schedule for Christopher Brown's newest MASS stock options?

The newest stock options (granted 2/28/2034) vest 25% on February 1, 2025, with the remaining 75% vesting in equal monthly installments over 36 months following February 1, 2025, subject to continued service.