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AWM Investment trims 908 Devices (MASS) stake with 186,942-share sale

Filing Impact
(Very High)
Filing Sentiment
(Negative)
Form Type
4

Rhea-AI Filing Summary

AWM Investment Company, Inc., a 10% owner of 908 Devices Inc., reported open-market sales totaling 186,942 shares of common stock through a limited partnership on May 27–28, 2026. Sale prices ranged from about $8.25 to $8.66 per share, leaving 4,929,773 shares indirectly held afterward. AWM reports these holdings as investment adviser to several funds and disclaims beneficial ownership beyond its pecuniary interest.

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Insider AWM Investment Company, Inc.
Role null
Sold 186,942 shs ($1.61M)
Type Security Shares Price Value
Sale 908 DEVICES, INC. 170,442 $8.6594 $1.48M
Sale 908 DEVICES, INC. 1,500 $8.25 $12K
Sale 908 DEVICES, INC. 15,000 $8.2527 $124K
Holdings After Transaction: 908 DEVICES, INC. — 4,929,773 shares (Indirect, By Limited Partnership)
Footnotes (1)
  1. This is a weighted average price 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. 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 2,054,000 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 588,327 Shares held by CAY, 271,986 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II.
Shares sold 186,942 shares Net open-market sales on May 27–28, 2026
May 28 sale price $8.6594 per share Weighted average price for 170,442-share sale
May 27 sale prices $8.2527 and $8.2500 per share Weighted average prices for 15,000- and 1,500-share sales
Post-transaction holdings 4,929,773 shares Indirect shares held after May 28, 2026 sale
Fund-level holdings 2,054,000; 588,327; 271,986; 338,137; 1,677,323 shares Shares held by SSFQP, CAY, SSPE, TECH, TECH II
open-market sale financial
"transaction_action: "open-market sale" for reported share dispositions"
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.
beneficial ownership financial
"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"
investment adviser financial
"AWM Investment Company, Inc. is the investment adviser to Special Situations funds"
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.
Section 16 of the Securities Exchange Act of 1934 financial
"shall not be deemed an admission that the reporting person is the beneficial owner of the securities reported herein for purposes of Section 16"
A provision of federal securities law that requires company insiders—directors, officers and large shareholders—to publicly report their stock holdings and trades and to surrender any “short-swing” profits from purchases and sales within a six-month window. It acts like a rule that forces leaders to announce their trades and prevents quick buy-sell windfalls, giving investors transparency into insider activity and reducing opportunities for unfair gain.
Form 4 Insider Transactions: What Each Field Means →
SEC Form 4
FORM 4UNITED 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)
DirectorX10% Owner
Officer (give title below)Other (specify below)
2a. Foreign Trading Symbol
3. Date of Earliest Transaction (Month/Day/Year)
05/27/2026		6. Individual or Joint/Group Filing (Check Applicable Line)
XForm 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)
CodeVAmount(A) or (D)Price
908 DEVICES, INC.05/27/2026S1,500D$8.25(1)5,115,215IBy Limited Partnership
908 DEVICES, INC.05/27/2026S15,000D$8.2527(1)5,100,215IBy Limited Partnership
908 DEVICES, INC.05/28/2026S170,442D$8.6594(1)4,929,773(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)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount or Number of Shares
Explanation of Responses:
1. This is a weighted average price
2. 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.
3. 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 2,054,000 shares of Common Stock of the Issuer (the Shares) held by SSFQP, 588,327 Shares held by CAY, 271,986 Shares held by SSPE, 338,137 Shares held by TECH and 1,677,323 Shares held by TECH II.
Adam Stettner05/29/2026
** Signature of Reporting PersonDate
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 selling 186,942 shares of 908 Devices common stock in open-market transactions on May 27–28, 2026. These indirect sales were executed through a limited partnership at prices around $8.25 to $8.66 per share.

How many 908 Devices (MASS) shares did AWM Investment Company sell and at what prices?

AWM sold 186,942 908 Devices shares in three open-market trades. The reported weighted average sale prices were approximately $8.25 and $8.25 per share on May 27, 2026, and $8.66 per share on May 28, 2026, through indirect limited partnership holdings.

How many 908 Devices (MASS) shares does AWM Investment Company hold after these sales?

After the reported transactions, AWM’s indirect holdings total 4,929,773 908 Devices shares. These shares are held through several investment funds for which AWM acts as investment adviser and has sole voting and investment power, subject to its pecuniary interest.

Were AWM Investment Company’s 908 Devices (MASS) sales direct or indirect holdings?

The reported 908 Devices sales were from indirect holdings, noted as “By Limited Partnership.” AWM is the investment adviser to multiple funds that own the shares and reports sole voting and investment power while disclaiming beneficial ownership beyond its pecuniary interest.

What does AWM’s Form 4 say about its beneficial ownership of 908 Devices (MASS)?

AWM states it is investment adviser to several funds holding 908 Devices shares and has sole voting and investment power over those positions. It disclaims beneficial ownership of the securities except to the extent of its pecuniary interest, consistent with Section 16 reporting conventions.