Kevin J. McCallion - 02 Mar 2026 Form 4/A - Amendment Insider Report for 908 Devices Inc. (MASS)

Signature
/s/ Mark S. Levine, Attorney-in-Fact
Issuer symbol
MASS
Transactions as of
02 Mar 2026
Net transactions value
$0
Form type
4/A - Amendment
Filing time
05 Mar 2026, 16:50:42 UTC
Date Of Original Report
04 Mar 2026
Previous filing
04 Mar 2026

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
McCallion Kevin J. SVP, Products and Production C/O 908 DEVICES INC., 44 3RD AVENUE, BURLINGTON /s/ Mark S. Levine, Attorney-in-Fact 04 Mar 2026 0002115341

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction MASS Common Stock Options Exercise +7 +0.02% $1.05* 44,932 02 Mar 2026 Direct F1
transaction MASS Common Stock Sale -7 -0.02% $7.00* 44,925 02 Mar 2026 Direct F1

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
transaction MASS Stock Option (right to buy) Options Exercise -7 -0.03% $0.000000* 26,686 02 Mar 2026 Common Stock 7 $1.05 Direct F1, F2
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Buy Plan / Sale Plan: These are also open market purchases/sales of shares, but in this case the transaction is part of a trading plan. Rule 10b5-1 allows insiders to setup a trading plan to buy/sell stocks over a certain period of time. Since the purchases/sales are predetermined, this protects the insiders from violating insider trading law.

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).

Explanation of Responses:

Id Content
F1 This transaction was made pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 9, 2025.
F2 The shares underlying the option are fully vested and immediately exercisable.