Latest filingSep 04, 2026Most recent Form 4
MASS
908 Devices Inc.
NasdaqIndustrialsLaboratory Analytical Instruments
Insider activity for last month from 08/05 to 09/05. Counts use processed Form 4 rows. Purchase and sale metrics use codes P and S; totals remain unknown when any matching value is missing. Rows without a usable transaction date cannot be assigned to a rolling period and are excluded.
Total buying$00 buys
Total selling$125M6 sells
Net open-market-$125M4 insiders
Open-market mix
Buy vs sell distribution by transaction countInsider activity report
Monthly open-market purchase and sale counts Buys Sells
Transaction codes
By Form 4 transaction code in selected period6transactions
- S · Open-market sells · dominant6 · 100%
Activity by reported role
A joint filing can contribute to multiple roles6transactions
- 10% owner · dominant2 · 33%
- PRES2 · 33%
- Chief financial officer1 · 17%
- Director1 · 17%
Distinct insiders active
Reporting-owner CIKs by month · peak Aug 2026 (3)Aug 2026Sep 2026
Reported Holdings After
Separated by insider, security, and ownership typeKnopp Kevin J.Common Stock · Direct
555,968Aug 17, 2026
AWM Investment Company, Inc.Common Stock · Indirect · By Limited Partnership
4,779,773Aug 21, 2026
Griffith Joseph H. IVCommon Stock · Direct
121,497Aug 25, 2026
Brown Christopher D.Common Stock · Direct
775,559Sep 02, 2026
These are reported post-transaction holdings, not company-wide ownership percentages. Securities, indirect vehicles, and amendments are kept separate.
Filing activity heatmap
Each cell is one day · intensity = transactions · buys green, sells redAug 05 → Sep 05
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Top insiders
By absolute net value across the selected period- AI-$529.8k
- BD-$317.4k
- KJ-$283.7k
Filing detail checks
Secondary metrics for the selected periodFiling-only signals
Deterministic matches in the selected period
MASS transaction history
Filters apply within this company and selected period by default| Ticker | Insider | Role | Type | Shares | Value | Code | Signals | 90d return | Filed | Trans date |
|---|---|---|---|---|---|---|---|---|---|---|
| MASS | Brown Christopher D. | DIR | sale10b5-1 | 30.0k | -$31.7M | S | — | 0.0% | 09/04 | 09/02 |
| MASS | AWM Investment Company, Inc. | 10% | sale | 41.5k | -$44.1M | S | +0.3% | 08/24 | 08/21 | |
| MASS | AWM Investment Company, Inc. | 10% | sale | 8.42k | -$8.86M | S | +0.3% | 08/24 | 08/20 | |
| MASS | Knopp Kevin J. | PRES | sale10b5-1 | 20.0k | -$20.7M | S | +4.5% | 08/17 | 08/17 | |
| MASS | Knopp Kevin J. | PRES | sale10b5-1 | 7.62k | -$7.66M | S | +4.5% | 08/17 | 08/13 |
908 Devices Inc. Insider Activity FAQ
SEC Form 4 contextWho recently reported transactions at 908 Devices Inc.?
Brown Christopher D., Griffith Joseph H. IV, AWM Investment Company, Inc., Knopp Kevin J..
When was the latest reported open-market purchase?
No code-P purchase is available for this period.
When was the latest reported open-market sale?
Brown Christopher D. reported a sale on Sep 02, 2026 valued at $31.7M. Read the SEC filing.
What is the recent purchase and sale balance?
Net open-market selling in the selected period was $1,256,350.76. Sales can occur for many non-investment reasons.
Where can I see the original SEC filing?
Every transaction row and latest-activity fact links to its original SEC filing.
What do these Form 4 transaction codes mean?
P and S generally describe open-market or private purchases and sales. A, D, F, M, X, G, J, and V describe awards, issuer dispositions, tax withholding, exercises, gifts, other transactions, and voluntary early reports; review each filing and its footnotes for context.