908 Devices director sells 30K shares at $10.58

A 908 Devices Inc. director sold 30,000 shares under a pre-arranged Rule 10b5-1 trading plan and continues to hold 775,559 shares.

Rhea-AI Filing Summary

908 Devices Inc. (MASS) director Christopher D. Brown reported selling 30,000 shares of common stock on September 2, 2026, at a weighted average price of $10.58 per share in open-market or private transactions. The sales were made pursuant to a Rule 10b5-1 trading plan adopted on November 24, 2025, and Brown now holds 775,559 shares directly.

Insider Trade Summary 10b5-1

Net Seller: 30,000 shares

Net Sell 1 txn

Insider Brown Christopher D.

Role Director

Sold 30,000 shs ($317K)

Type	Security	Shares	Price	Value
Sale	Common Stock F1, F2	30,000	$10.58	$317K

Holdings After Transaction: Common Stock — 775,559 shares (Direct)

Footnotes (2)

1. F1. This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 24, 2025.
2. F2. The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $10.33 to $10.97 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

Key Figures

Shares sold: 30,000 shares Weighted average sale price: $10.58 per share Sale price range: $10.33–$10.97 per share +2 more

5 metrics

Shares sold 30,000 shares Sale of common stock on September 2, 2026

Weighted average sale price $10.58 per share Sale of 30,000 shares on September 2, 2026

Sale price range $10.33–$10.97 per share Multiple transactions included in the 30,000-share sale

Holdings after transaction 775,559 shares Direct ownership position after the September 2, 2026 sale

10b5-1 plan adoption date November 24, 2025 Rule 10b5-1 trading plan governing the reported sale

Key Terms

Rule 10b5-1 trading plan, weighted average price, open market or private transaction

3 terms

Rule 10b5-1 trading plan regulatory

"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted"

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

weighted average price financial

"The price reported is a weighted average price."

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

open market or private transaction financial

"Sale in open market or private transaction"

FAQ

What insider transaction did 908 Devices Inc. (MASS) report for Christopher D. Brown?

Christopher D. Brown reported a sale of 30,000 shares of 908 Devices Inc. common stock on September 2, 2026, in a transaction coded as a sale in an open market or private transaction.

At what price were the MASS shares sold in this Form 4 filing?

The filing reports a weighted average price of $10.58 per share. A footnote explains the shares were sold in multiple transactions at prices ranging from $10.33 to $10.97 inclusive.

How many 908 Devices Inc. (MASS) shares does Christopher D. Brown hold after this sale?

After the reported sale, Christopher D. Brown directly holds 775,559 shares of 908 Devices Inc. common stock, according to the Form 4.

Was the MASS insider sale made under a Rule 10b5-1 trading plan?

Yes. The filing states the transaction was made pursuant to a Rule 10b5-1 trading plan adopted by Christopher D. Brown on November 24, 2025.

What type of transaction code is reported in this MASS Form 4?

The transaction is coded as S, described as a sale in open market or private transaction, covering 30,000 shares of common stock.

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Available on EDGAR 09/04/2026 - 04:16 PM Accepted by SEC EDGAR 09/04/2026 - 04:15 PM Learn about SEC filing dates

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^*

Brown Christopher D.

(Last) (First) (Middle)

C/O 908 DEVICES INC.

44 3RD AVENUE

(Street)

BURLINGTON MASSACHUSETTS 01803

(City) (State) (Zip)

UNITED STATES

(Country)

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

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

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/02/2026

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

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

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

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	09/02/2026		S(1)		30,000	D	$10.58(2)	775,559	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

Explanation of Responses:

1. This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 24, 2025.

2. The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $10.33 to $10.97 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

	/s/ Mark S. Levine, Attorney-in-Fact	09/04/2026
	** 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.
* Form 4: SEC 1474 (03-26)