AWM Investment Co. funds trim 908 Devices (MASS) stake with 42K-share sale

Filing Impact

(Moderate)

Filing Sentiment

(Negative)

Form Type

Rhea-AI Filing Summary

AWM Investment Company, Inc., as investment adviser to several funds, reported open-market sales of 908 Devices Inc. common stock held indirectly through limited partnerships. The transactions covered 39,782 shares at a weighted-average price of $8.9703 on June 4, 2026 and 2,500 shares at $8.95 on June 2, 2026. After these sales, entities advised by AWM reported holding 4,887,491 shares indirectly. AWM and its principals disclaim beneficial ownership of these shares except to the extent of their pecuniary interest.

Insider Trade Summary

Net Seller: 42,282 shares ($379,231)

Net Sell 2 txns

Insider AWM Investment Company, Inc.

Role null

Sold 42,282 shs ($379K)

Type	Security	Shares	Price	Value
Sale	908 DEVICES, INC.	39,782	$8.9703	$357K
Sale	908 DEVICES, INC.	2,500	$8.95	$22K

Holdings After Transaction: 908 DEVICES, INC. — 4,887,491 shares (Indirect, By Limited Partnership)

Footnotes (1)

This is a weighted average price. AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds). As the investment adviser to the Funds, AWM holds sole voting and investment power over 2,025,616 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 578,813 Shares held by CAY, 267,602 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II. David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose.

Key Figures

Shares sold (total): 42,282 shares Sale on June 4, 2026: 39,782 shares at $8.9703 Sale on June 2, 2026: 2,500 shares at $8.95 +4 more

7 metrics

Shares sold (total) 42,282 shares Two open-market sales reported in Form 4

Sale on June 4, 2026 39,782 shares at $8.9703 Weighted-average sale price, open-market transaction

Sale on June 2, 2026 2,500 shares at $8.95 Open-market sale of common stock

Shares held after transactions 4,887,491 shares Indirect ownership via limited partnerships after sales

SSFQP holding 2,025,616 shares Shares with sole voting and investment power via SSFQP

CAY holding 578,813 shares Shares with sole voting and investment power via CAY

TECH II holding 1,677,323 shares Shares with sole voting and investment power via TECH II

Key Terms

open-market sale, weighted average price, investment adviser, beneficial ownership, +2 more

6 terms

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.

weighted average price financial

"This 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.

investment adviser financial

"AWM Investment Company, Inc. ... is the investment adviser to Special Situations Fund III QP, L.P."

An investment adviser is a person or firm that professionally manages money and gives recommendations about buying, selling, or holding investments. Like a financial coach or guide, they have a legal duty to act in a client's best financial interest, so their advice, fees and potential conflicts can directly affect returns and risk — making their role important for investors who want informed, accountable help with portfolios.

beneficial ownership financial

"The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein."

Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.

pecuniary interest financial

"disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein."

Section 16 regulatory

"for purposes of Section 16 of the Securities Exchange Act of 1934, as amended"

Section 16 is a U.S. securities law rule that governs the trading and disclosure obligations of company insiders — typically officers, directors and large shareholders — to promote transparency and deter unfair profit-taking. It requires insiders to publicly report their stock trades and allows companies or the issuer to reclaim quick, short-term profits from certain insider trades, like a scoreboard and a refund policy that help investors see and limit possible insider advantage.

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Form 4 Insider Transactions: What Each Field Means →

06/04/2026 - 04:43 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^*

AWM Investment Company, Inc.

(Last)

(First)

(Middle)

527 MADISON AVENUE

SUITE 2600

(Street)

NEW YORK

10022

(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)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
06/02/2026

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)
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)
908 DEVICES, INC.	06/02/2026		S		2,500	D	$8.95⁽¹⁾	4,927,273	I	By Limited Partnership
908 DEVICES, INC.	06/04/2026		S		39,782	D	$8.9703⁽¹⁾	4,887,491⁽²⁾⁽³⁾	I⁽²⁾⁽³⁾	By Limited Partnership⁽²⁾⁽³⁾

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 is a weighted average price.

2. AWM Investment Company, Inc., a Delaware Corporation (AWM), is the investment adviser to Special Situations Fund III QP, L.P. (SSFQP), Special Situations Cayman Fund, L.P. (CAY), Special Situations Private Equity Fund, L.P. (SSPE), Special Situations Technology Fund, L.P. (TECH) and Special Situations Technology Fund II, L.P. (TECH II and together with SSFQP, CAY, SSPE and TECH, the Funds). As the investment adviser to the Funds, AWM holds sole voting and investment power over 2,025,616 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 578,813 Shares held by CAY, 267,602 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II.

3. David M. Greenhouse (Greenhouse) and Adam C. Stettner (Stettner) are the controlling principals of AWM. The reporting person disclaims beneficial ownership of the Shares, except to the extent of its pecuniary interest therein. This report shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose.

	Adam Stettner	06/04/2026
	** 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)

Source: View Original Filing on SEC EDGAR

FAQ

What insider transactions did AWM Investment Company report for 908 Devices (MASS)?

AWM Investment Company reported two open-market sales of 908 Devices common stock. Funds it advises sold 39,782 shares at a weighted-average price of $8.9703 on June 4, 2026, and 2,500 shares at $8.95 on June 2, 2026.

How many 908 Devices (MASS) shares were sold in total in this Form 4?

The filing shows total sales of 42,282 908 Devices shares. These consisted of 39,782 shares sold on June 4, 2026 and 2,500 shares sold on June 2, 2026, all reported as open-market transactions by funds advised by AWM Investment Company.

What is AWM’s reported 908 Devices (MASS) position after these sales?

After the reported transactions, entities advised by AWM show indirect ownership of 4,887,491 908 Devices shares. These are held through several limited partnerships, and the Form 4 clarifies that AWM reports them as indirect holdings by limited partnership.

How are the 908 Devices (MASS) shares distributed among AWM-advised funds?

The filing states AWM has sole voting and investment power over 2,025,616 shares via SSFQP, 578,813 via CAY, 267,602 via SSPE, 338,137 via TECH, and 1,677,323 via TECH II. Together, these positions represent the funds’ reported 908 Devices common stock holdings.

Does AWM Investment Company claim beneficial ownership of the 908 Devices (MASS) shares?

The Form 4 specifies that AWM disclaims beneficial ownership of the shares, except to the extent of its pecuniary interest. It also states the report should not be deemed an admission of beneficial ownership for Section 16 or other purposes.

Who controls AWM Investment Company in relation to this 908 Devices (MASS) filing?

The filing identifies David M. Greenhouse and Adam C. Stettner as controlling principals of AWM Investment Company. AWM serves as investment adviser to several Special Situations funds that hold the reported 908 Devices common stock positions.