AWM Investment sells 5,000 908 Devices shares

AWM Investment Company, Inc., a 10% owner of 908 Devices Inc., reported an indirect open-market sale of 5,000 shares of Common Stock at a weighted average price of $8.2514 per share on May 11, 2026.

Rhea-AI Filing Summary

AWM Investment Company, Inc., a 10% owner of 908 Devices Inc., reported an indirect open-market sale of 5,000 shares of Common Stock at a weighted average price of $8.2514 per share on May 11, 2026.

The shares are held through a limited partnership, and AWM reports indirect ownership. After this transaction, entities advised by AWM collectively held 5,116,715 shares of 908 Devices Common Stock. AWM and its principals disclaim beneficial ownership beyond their pecuniary interest.

Insider Trade Summary

Net Seller: 5,000 shares

Net Sell 1 txn

Insider AWM Investment Company, Inc.

Role 10% Owner

Sold 5,000 shs ($41K)

Type	Security	Shares	Price	Value
Sale	Common Stock	5,000	$8.2514	$41K

Holdings After Transaction: Common Stock — 5,116,715 shares (Indirect, By Limited Partnership)

Footnotes (3)

1. F1. This is a weighted average price.
2. F2. 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 2,179,495 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 630,388 Shares held by CAY, 291,372 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II.
3. F3. 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: 5,000 shares Sale price: $8.2514 per share Shares held after sale: 5,116,715 shares +5 more

8 metrics

Shares sold 5,000 shares Open-market sale of Common Stock on May 11, 2026

Sale price $8.2514 per share Weighted average sale price for 5,000-share transaction

Shares held after sale 5,116,715 shares Indirect holdings by AWM-advised entities following transaction

SSFQP holdings 2,179,495 shares Common Stock held by Special Situations Fund III QP, L.P.

CAY holdings 630,388 shares Common Stock held by Special Situations Cayman Fund, L.P.

SSPE holdings 291,372 shares Common Stock held by Special Situations Private Equity Fund, L.P.

TECH holdings 338,137 shares Common Stock held by Special Situations Technology Fund, L.P.

TECH II holdings 1,677,323 shares Common Stock held by Special Situations Technology Fund II, L.P.

Key Terms

open-market sale, indirect ownership, beneficial ownership, pecuniary interest, +1 more

5 terms

open-market sale financial

"transaction_action is described as an open-market sale of Common Stock"

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.

indirect ownership financial

"the transaction is reported as indirect, with ownership via a limited partnership"

beneficial ownership financial

"the reporting person disclaims beneficial ownership of the Shares"

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

"beneficial ownership is disclaimed except to the extent of its pecuniary interest"

Section 16 regulatory

"the securities are reported for purposes of Section 16 of the Exchange Act"

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.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

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

AWM Investment Company, Inc. reported selling 5,000 908 Devices shares. The indirect open-market sale of Common Stock occurred on May 11, 2026 at a weighted average price of $8.2514 per share, as disclosed in a Form 4 filing.

How many 908 Devices (MASS) shares does AWM hold after this Form 4 transaction?

After the sale, AWM-associated entities held 5,116,715 shares. The filing states that, following the 5,000-share open-market sale, funds advised by AWM collectively owned 5,116,715 shares of 908 Devices Common Stock on an indirect basis.

Was the 908 Devices (MASS) insider trade by AWM a buy or a sell?

The reported insider trade was a sale of shares. AWM’s Form 4 describes an open-market sale of 5,000 shares of 908 Devices Common Stock, coded as an “S” transaction and classified as a non-derivative, indirect disposition.

At what price did AWM’s affiliated fund sell 908 Devices (MASS) shares?

The 5,000 shares were sold at a weighted average price of $8.2514. The filing notes this weighted average sale price for the Common Stock transaction executed on May 11, 2026, and identifies the price detail as a weighted average in a footnote.

How is AWM’s ownership in 908 Devices (MASS) structured according to the Form 4?

AWM’s interest is held indirectly through several investment funds. The filing explains that AWM advises multiple limited partnerships that hold 908 Devices shares, and AWM has sole voting and investment power over those fund-held positions while disclaiming beneficial ownership beyond pecuniary interest.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 05/13/2026 - 04:49 PM EDT 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).

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 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)
05/11/2026

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	05/11/2026		S		5,000	D	$8.2514(1)	5,116,715(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)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

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 2,179,495 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 630,388 Shares held by CAY, 291,372 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	05/13/2026
	** 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)