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908 Devices (MASS) CEO offloads 27K shares under preset 10b5-1 plan

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

Rhea-AI Filing Summary

908 Devices Inc. insider Kevin J. Knopp, President and CEO, reported selling a total of 27,622 shares of common stock in August 2026 under a Rule 10b5-1 trading plan adopted on May 20, 2025. Sales included 7,622 shares on August 13 at a weighted average $10.06 per share (actual prices ranged from $10.05 to $10.12) and 20,000 shares on August 17 at a weighted average $10.35 per share (range $10.08 to $10.45). Separately, 541,223 shares are held indirectly by The Kevin J. Knopp Irrevocable Trust of 2018, for which the trustee, Knopp’s brother-in-law, has sole voting and dispositive control; Knopp may be deemed the beneficial owner.

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Insider Knopp Kevin J.
Role President and CEO
Sold 27,622 shs ($284K)
Type Security Shares Price Value
Sale Common Stock F1, F3 20,000 $10.35 $207K
Sale Common Stock F1, F2 7,622 $10.06 $77K
holding Common Stock F4 -- -- --
Holdings After Transaction: Common Stock — 555,968 shares (Direct); Common Stock — 541,223 shares (Indirect, See footnote)
Footnotes (4)
  1. F1. This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 20, 2025.
  2. F2. The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $10.05 to $10.12 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 range set forth in this footnote.
  3. F3. The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $10.08 to $10.45 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 range set forth in this footnote.
  4. F4. The shares are owned directly by The Kevin J. Knopp Irrevocable Trust of 2018. The reporting person's brother-in-law is the trustee of The Kevin J. Knopp Irrevocable Trust of 2018 and has sole voting and dispositive control with respect to all securities held by such trust. The reporting person may be deemed to be the beneficial owner of the securities held by The Kevin J. Knopp Irrevocable Trust of 2018.
Shares sold 2026-08-17 20,000 shares Common stock sale at weighted average price of $10.35 per share
Price 2026-08-17 $10.35 per share Weighted average; actual sale prices ranged from $10.08 to $10.45
Shares sold 2026-08-13 7,622 shares Common stock sale at weighted average price of $10.06 per share
Price 2026-08-13 $10.06 per share Weighted average; actual sale prices ranged from $10.05 to $10.12
Total shares sold 27,622 shares Sum of August 13 and August 17 2026 sales reported for Kevin J. Knopp
Indirect trust holdings 541,223 shares Common stock held by The Kevin J. Knopp Irrevocable Trust of 2018
10b5-1 plan adoption date May 20, 2025 Adoption date of Rule 10b5-1 trading plan governing the reported sales
Rule 10b5-1 trading plan regulatory
"This transaction was made pursuant to a Rule 10b5-1 trading plan adopted"
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 is a weighted average price. These shares were sold"
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.
beneficial owner financial
"The reporting person may be deemed to be the beneficial owner of"
A beneficial owner is the person who ultimately owns or controls a financial asset or property, even if their name isn't directly on official documents. Think of it like someone who secretly holds the keys to a safe deposit box—others may appear to have access, but the true owner is the one who benefits from what's inside. Identifying beneficial owners helps ensure transparency and prevent illegal activities like money laundering or fraud.
dispositive control financial
"has sole voting and dispositive control with respect to all securities"

FAQ

What insider stock sales did MASS (908 Devices Inc.) report for Kevin J. Knopp?
Kevin J. Knopp reported selling a total of 27,622 shares of 908 Devices Inc. common stock in August 2026. The sales were executed in two transactions on August 13 and August 17 under a Rule 10b5-1 trading plan adopted on May 20, 2025.

At what prices did Kevin J. Knopp sell MASS shares in August 2026?
On August 13, Knopp sold 7,622 shares at a weighted average price of $10.06 per share. On August 17, he sold 20,000 shares at a weighted average of $10.35 per share, with actual trade prices within the disclosed ranges.

Were Kevin J. Knopp’s MASS stock sales made under a Rule 10b5-1 plan?
Yes. The reported August 2026 stock sales by Kevin J. Knopp were made pursuant to a Rule 10b5-1 trading plan adopted on May 20, 2025. This plan-based structure pre-arranges trading parameters independent of subsequent market or company developments.

How many MASS shares are held indirectly for Kevin J. Knopp through a trust?
An indirect holding entry shows 541,223 shares of 908 Devices Inc. common stock held by The Kevin J. Knopp Irrevocable Trust of 2018. The trustee, Knopp’s brother-in-law, has sole voting and dispositive control; Knopp may be deemed the beneficial owner.

Who has voting and dispositive control over the MASS shares held in The Kevin J. Knopp Irrevocable Trust of 2018?
The trustee, who is Kevin J. Knopp’s brother-in-law, has sole voting and dispositive control over all 908 Devices Inc. shares held by The Kevin J. Knopp Irrevocable Trust of 2018, though Knopp may be deemed the beneficial owner of those securities.

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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).
X
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*
Knopp Kevin J.
(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)
XDirector10% Owner
XOfficer (give title below)Other (specify below)
President and CEO
2a. Foreign Trading Symbol
3. Date of Earliest Transaction (Month/Day/Year)
08/13/2026		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
Common Stock08/13/2026S(1)7,622D$10.06(2)575,968D
Common Stock08/17/2026S(1)20,000D$10.35(3)555,968D
Common Stock541,223ISee footnote(4)
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 transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 20, 2025.
2. The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $10.05 to $10.12 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 range set forth in this footnote.
3. The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $10.08 to $10.45 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 range set forth in this footnote.
4. The shares are owned directly by The Kevin J. Knopp Irrevocable Trust of 2018. The reporting person's brother-in-law is the trustee of The Kevin J. Knopp Irrevocable Trust of 2018 and has sole voting and dispositive control with respect to all securities held by such trust. The reporting person may be deemed to be the beneficial owner of the securities held by The Kevin J. Knopp Irrevocable Trust of 2018.
/s/ Mark S. Levine, Attorney-in-Fact08/17/2026
** 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