908 Devices Inc. (MASS) holder AWM sells 50,000 shares, keeps 4.83M

Rhea-AI Filing Summary

AWM Investment Company, Inc., a ten percent owner of 908 Devices Inc., reported an indirect sale of 50,000 shares of Common Stock on August 4, 2026 at a weighted average price of $8.3553 per share. The shares are held through limited partnerships advised by AWM, which reported aggregate post-transaction holdings of 4,829,773 shares and disclaimed beneficial ownership except to the extent of its pecuniary interest.

Insider Trade Summary

Net Seller: 50,000 shares

Net Sell 1 txn

Insider AWM Investment Company, Inc.

Role 10% Owner

Sold 50,000 shs ($418K)

Type	Security	Shares	Price	Value
Sale	Common Stock F2, F3, F1	50,000	$8.3553	$418K

Holdings After Transaction: Common Stock — 4,829,773 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 2,020,434 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 577,077 Shares held by CAY, 216,802 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: 50,000 shares Sale price (weighted average): $8.3553 per share Shares held after transaction: 4,829,773 shares +5 more

8 metrics

Shares sold 50,000 shares Common Stock sold on August 4, 2026 by AWM-associated limited partnership

Sale price (weighted average) $8.3553 per share Weighted average sale price for the 50,000 shares of Common Stock

Shares held after transaction 4,829,773 shares Aggregate 908 Devices Inc. Common Stock held by AWM-advised funds after the sale

SSFQP holdings 2,020,434 shares Shares of Common Stock held by Special Situations Fund III QP, L.P.

CAY holdings 577,077 shares Shares of Common Stock held by Special Situations Cayman Fund, L.P.

SSPE holdings 216,802 shares Shares of Common Stock held by Special Situations Private Equity Fund, L.P.

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

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

Key Terms

weighted average price, investment adviser, beneficial ownership, pecuniary interest, +1 more

5 terms

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 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"

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"

ten percent owner financial

"AWM Investment Company, Inc. is a ten percent owner of the issuer"

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

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 08/06/2026 - 04:26 PM Accepted by SEC EDGAR 08/06/2026 - 04:26 PM Learn about SEC filing dates

FAQ

What insider transaction involving 908 Devices Inc. (MASS) did AWM report?

AWM Investment Company, Inc. reported an indirect sale of 50,000 shares of 908 Devices Inc. Common Stock. The transaction occurred on August 4, 2026 and was reported as a sale in the open market or a private transaction at a weighted average price.

How many MASS shares did AWM sell and at what price?

AWM sold 50,000 shares of 908 Devices Inc. (MASS) at a weighted average price of $8.3553 per share. The price is explicitly described as a weighted average, meaning individual trade prices within the transaction may have varied around this average level.

What are AWM’s remaining MASS holdings after this transaction?

After the sale, AWM-reported funds held an aggregate of 4,829,773 shares of 908 Devices Inc. (MASS) Common Stock. These shares are held indirectly through several limited partnership funds for which AWM acts as investment adviser and has sole voting and investment power.

How are AWM’s MASS shares allocated among its funds?

AWM, as investment adviser, has sole voting and investment power over 2,020,434 shares held by SSFQP, 577,077 by CAY, 216,802 by SSPE, 338,137 by TECH, and 1,677,323 by TECH II, all in 908 Devices Inc. (MASS) Common Stock.

Does AWM claim full beneficial ownership of its MASS holdings?

AWM expressly disclaims beneficial ownership of the 908 Devices Inc. (MASS) shares it reports, except to the extent of its pecuniary interest. The report states it should not be deemed an admission of beneficial ownership of the securities for Section 16 or any other purpose.

Is AWM’s ownership in MASS direct or indirect?

AWM’s reported 908 Devices Inc. (MASS) holdings are indirect, held “By Limited Partnership.” The shares are owned by multiple funds—such as SSFQP, CAY, SSPE, TECH, and TECH II—for which AWM serves as investment adviser with sole voting and investment power.

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)
08/04/2026

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	08/04/2026		S		50,000(2)(3)	D	$8.3553(1)	4,829,773(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 2,020,434 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 577,077 Shares held by CAY, 216,802 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	08/06/2026
	** 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)