InsiderTrades

Form 4 for MASS 908 Devices Inc.

Accepted 2026-06-25 16:15:08 ET · period of report 2026-06-25 · accession 0002027457-26-000005 · SEC index · Original document

Summary rows

Aggregated the way they appear in lists: one row per insider, transaction code and security table.

X Filed Traded Ticker Insider Title Type Price Qty Owned ΔOwn Value
D 2026-06-25 16:15 2026-06-25 MASS Leonhart Michele M. Dir M - OptEx — +6,486 27.1K +32% —
D 2026-06-25 16:15 2026-06-25 MASS Leonhart Michele M. Dir M - OptEx $0.00 -6,486 6,485 -50% $0

Purchase Sale Sale after option exercise All abbreviations

Every reported transaction

#TableSecurityDateCodeA/DSharesPriceOwned afterOwnExercise / expiryUnderlyingFootnotes
1 Common Common Stock 2026-06-25 M A 6,486 — 27,054 D — — (F1) Each Restricted Stock Unit ("RSU") represents a contingent right to receive one share of Common Stock, par value $0.001, when vested.
2 Derivative Restricted Stock Units 2026-06-25 M D 6,486 $0.00 6,485 D — · — to — 6,486 Common Stock (F1) Each Restricted Stock Unit ("RSU") represents a contingent right to receive one share of Common Stock, par value $0.001, when vested. (F2) The RSUs become vested in substantially equal annual installments over the 3 years following June 25, 2024, subject to the reporting person's continued service through the applicable vesting date, provided that, if the reporting person terminates their service for any reason, then a prorated number of RSUs will vest. The RSUs have no expiration date. (F2) The RSUs become vested in substantially equal annual installments over the 3 years following June 25, 2024, subject to the reporting person's continued service through the applicable vesting date, provided that, if the reporting person terminates their service for any reason, then a prorated number of RSUs will vest. The RSUs have no expiration date.