Over what dates did the 908 Devices (MASS) insider share sales occur?

The reported insider share sales occurred on April 8, April 9, and April 10, 2026. Each day’s transactions involved open-market sales of 908 Devices Common Stock at weighted average prices slightly above $7 per share, as detailed in the Form 4 filing.

908 Devices (NASDAQ: MASS) director sells 40,000 shares under 10b5-1 plan

Filing Impact

(Moderate)

Filing Sentiment

(Negative)

Form Type

Rhea-AI Filing Summary

908 Devices Inc. director Christopher D. Brown reported open-market sales of 40,000 shares of Common Stock. The transactions occurred over three days at prices around $7 per share, under a Rule 10b5-1 trading plan adopted on November 24, 2025.

Brown sold 15,030 shares at a weighted average price of $7.05 on April 8, 7,392 shares at $7.04 on April 9, and 17,578 shares at $7.07 on April 10. After these sales, he continues to hold 945,559 shares directly, indicating he retains a substantial equity position in the company.

Insider Trade Summary 10b5-1

Net Seller: 40,000 shares ($282,278)

Net Sell 3 txns

Insider Brown Christopher D.

Role Director

Sold 40,000 shs ($282K)

Type	Security	Shares	Price	Value
Sale	Common Stock	17,578	$7.07	$124K
Sale	Common Stock	7,392	$7.04	$52K
Sale	Common Stock	15,030	$7.05	$106K

Holdings After Transaction: Common Stock — 945,559 shares (Direct)

Footnotes (1)

This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 24, 2025. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $7.00 to $7.25 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 ranges set forth in footnotes (2), (3) and (4). The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $7.00 to $7.10 inclusive. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $7.00 to $7.14 inclusive.

Key Figures

Total shares sold: 40,000 shares Sale on April 8, 2026: 15,030 shares at $7.05/share Sale on April 9, 2026: 7,392 shares at $7.04/share +3 more

6 metrics

Total shares sold 40,000 shares Aggregate open-market sales reported in April 2026

Sale on April 8, 2026 15,030 shares at $7.05/share Weighted average price for that day’s transactions

Sale on April 9, 2026 7,392 shares at $7.04/share Weighted average price for that day’s transactions

Sale on April 10, 2026 17,578 shares at $7.07/share Weighted average price for that day’s transactions

Shares held after transactions 945,559 shares Direct ownership after April 10, 2026 sale

Net share change 40,000 shares sold transactionSummary net-sell shares

Key Terms

Rule 10b5-1 trading plan, weighted average price, open-market sale, Common Stock

4 terms

Rule 10b5-1 trading plan financial

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

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 in Column 4 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 sale financial

"transaction_action: open-market sale"

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

Common Stock financial

"security_title: Common Stock"

Common stock represents ownership shares in a company, giving investors a stake in its success and a say in important decisions through voting rights. It is the most common type of stock traded on markets and can provide income through dividends, as well as potential for value growth. For investors, holding common stock means sharing in the company’s profits and risks.

Form 4 Insider Transactions: What Each Field Means →

04/10/2026 - 06:37 PM

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).

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)
04/08/2026

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	04/08/2026		S⁽¹⁾		15,030	D	$7.05⁽²⁾	970,529	D
Common Stock	04/09/2026		S⁽¹⁾		7,392	D	$7.04⁽³⁾	963,137	D
Common Stock	04/10/2026		S⁽¹⁾		17,578	D	$7.07⁽⁴⁾	945,559	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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)

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 in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $7.00 to $7.25 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 ranges set forth in footnotes (2), (3) and (4).

3. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $7.00 to $7.10 inclusive.

4. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $7.00 to $7.14 inclusive.

	/s/ Mark S. Levine, Attorney-in-Fact	04/10/2026
	** 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)

Source: View Original Filing on SEC EDGAR

FAQ

What did 908 Devices (MASS) director Christopher D. Brown report in this Form 4?

Christopher D. Brown reported selling 40,000 shares of 908 Devices Common Stock in open-market transactions. The sales took place over three days in April 2026 at prices around $7 per share, under a pre-arranged Rule 10b5-1 trading plan.

How many 908 Devices (MASS) shares did Christopher D. Brown sell and at what prices?

Brown sold a total of 40,000 shares of 908 Devices. He sold 15,030 shares at $7.05, 7,392 shares at $7.04, and 17,578 shares at $7.07. Footnotes note these are weighted averages from multiple trades within specified price ranges.

How many 908 Devices (MASS) shares does Christopher D. Brown hold after these sales?

After completing the reported transactions, Christopher D. Brown holds 945,559 shares of 908 Devices Common Stock directly. This figure, disclosed in the filing, shows he retains a significant ownership stake even after selling 40,000 shares in the open market.

Were the 908 Devices (MASS) insider sales made under a Rule 10b5-1 plan?

Yes. A footnote states the transactions were made under a Rule 10b5-1 trading plan adopted by Christopher D. Brown on November 24, 2025. Such plans pre-schedule trades, which can make the timing of sales less indicative of short-term views.