Kevin J. McCallion - 10 Apr 2026 Form 4 Insider Report for 908 Devices Inc. (MASS)

Reporting relationship: SVP, Products and Production
Issuer ticker: MASS
Reported as of: 10 Apr 2026
Net transaction value: -$18,878
SEC form: 4
Accepted by SEC: 14 Apr 2026, 16:00:05 UTC
Prior SEC filing: 10 Apr 2026
Source filing: View source filing
Reporting owner signature: /s/ Mark S. Levine, Attorney-in-Fact

Key filing fact

Kevin J. McCallion filed Form 4 for 908 Devices Inc. (MASS) on 14 Apr 2026.

Key facts

This page summarizes Kevin J. McCallion's Form 4 filing for 908 Devices Inc. (MASS).
3 reported transactions and 1 derivative row are listed below.
Accepted by SEC: 14 Apr 2026, 16:00.

Change

Previous filing in this sequence was filed on 10 Apr 2026.
Current net transaction value: -$18,878.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0002115341 Primary reporting owner

McCallion Kevin J.

Relationship: SVP, Products and Production
Address: C/O 908 DEVICES INC., 44 3RD AVENUE, BURLINGTON
Signature: /s/ Mark S. Levine, Attorney-in-Fact
Signature date: 14 Apr 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

MASS transaction

Common Stock

Options Exercise

Transaction value
Shares: +2,693
Change %: +6%
Price: $1.05^*
Shares after: 47,618
Date: 10 Apr 2026
Ownership: Direct
Footnotes: F1

MASS transaction

Common Stock

Sale

Transaction value: $18,878
Shares: -2,693
Change %: -5.7%
Price: $7.01
Shares after: 44,925
Date: 10 Apr 2026
Ownership: Direct
Footnotes: F1, F2

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

MASS transaction Derivative

Stock Option (right to buy)

Options Exercise

Transaction value
Shares: -2,693
Change %: -100%
Price: $0.000000^*
Shares after: 0
Date: 10 Apr 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 2,693
Exercise price: $1.05
Footnotes: F1, F3, F4

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Rule 10b5-1 trading plan

These transactions were reported as open-market trades under a Rule 10b5-1 plan. The plan lets an insider set trading instructions in advance, which can reduce the risk of trading while in possession of material nonpublic information.

Original filing language: transaction made pursuant to a contract, instruction, or written plan intended to satisfy Rule 10b5-1(c).

Explanation of responses 4 footnotes

Footnote F1

This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 9, 2025.

Footnote F2

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $7.00 to $7.03 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.

Footnote F3

The shares underlying the option are fully vested and immediately exercisable.

Footnote F4

Due to a scrivener's error on the Form 3, the number of stock options beneficially owned by the Reporting Person pursuant to this grant was understated by 7. Following this transaction, the entire option grant has been exercised.