MASS insider buying and SEC filings, explained
908 Devices Inc. · CIK 1555279
Tracked: Forms 3/4/5, 8-K, NT · All filings on sec.gov
Insider activity in the last 12 months
Bought
$0
Insiders who bought
0
Sold (not marked 10b5-1)
$4.7M
Planned sales (10b5-1)
$5.2M
Insider purchases and sales, last 12 months
| Traded | Type | What was filed | Source |
|---|---|---|---|
| Oct 7, 2026 | Planned (10b5-1) | Christopher D. Brown (Director) sold 30,000 shares at about $11.89 ($357K), marked as a 10b5-1 plan trade. Holdings down 4% to 745,559 shares. | SEC filing Filed Oct 9, 2026, 4:15 PM ET |
| Oct 6, 2026 | Planned (10b5-1) | Joseph H. Griffith IV (CFO) sold 5,000 shares at $13.03 ($65K), marked as a 10b5-1 plan trade. Holdings down 4% to 116,497 shares. | SEC filing Filed Oct 8, 2026, 4:43 PM ET |
| Sep 29, 2026 | Sale | AWM Investment Company, Inc. (10% owner) sold 18,000 shares indirectly (by entity) at about $11.52 ($207K). Holdings by entity down <1% to 4,736,773 shares. Not marked as a 10b5-1 plan trade. | SEC filing Filed Oct 1, 2026, 5:02 PM ET |
| Sep 23–24, 2026 | Sale | AWM Investment Company, Inc. (10% owner) sold 25,000 shares indirectly (by entity) between Sep 23 and Sep 24 at about $11.36 ($284K). Holdings by entity down 1% to 4,754,773 shares. Not marked as a 10b5-1 plan trade. | SEC filing Filed Sep 25, 2026 |
| Sep 15–17, 2026 | Planned (10b5-1) | John Kenneweg (SVP, Sales & Product Marketing) sold 27,656 shares between Sep 15 and Sep 17 at about $10.13 ($280K), marked as a 10b5-1 plan trade. Holdings down 32% to 57,784 shares. | SEC filing Filed Sep 17, 2026 |
| Sep 2, 2026 | Planned (10b5-1) | Christopher D. Brown (Director) sold 30,000 shares at about $10.58 ($317K), marked as a 10b5-1 plan trade. Holdings down 4% to 775,559 shares. | SEC filing Filed Sep 4, 2026 |
| Aug 25, 2026 | Planned (10b5-1) | Joseph H. Griffith IV (CFO) sold 11,459 shares at about $10.95 ($125K), marked as a 10b5-1 plan trade. Holdings down 9% to 121,497 shares. | SEC filing Filed Aug 27, 2026 |
| Aug 20–21, 2026 | Sale | AWM Investment Company, Inc. (10% owner) sold 50,000 shares indirectly (by entity) between Aug 20 and Aug 21 at about $10.59 ($530K). Holdings by entity down 1% to 4,779,773 shares. Not marked as a 10b5-1 plan trade. | SEC filing Filed Aug 24, 2026 |
| Aug 13–17, 2026 | Planned (10b5-1) | Kevin J. Knopp (CEO and Director) sold 27,622 shares between Aug 13 and Aug 17 at about $10.27 ($284K), marked as a 10b5-1 plan trade. Holdings down 5% to 555,968 shares. | SEC filing Filed Aug 17, 2026 |
| Aug 10–11, 2026 | Planned (10b5-1) | Christopher D. Brown (Director) sold 17,800 shares between Aug 10 and Aug 11 at about $9.12 ($162K), marked as a 10b5-1 plan trade. Holdings down 2% to 805,559 shares. | SEC filing Filed Aug 12, 2026 |
| Aug 10–12, 2026 | Planned (10b5-1) | Kevin J. Knopp (CEO and Director) sold 149,013 shares between Aug 10 and Aug 12 at about $9.90 ($1.5M), marked as a 10b5-1 plan trade. Holdings down 20% to 583,590 shares. | SEC filing Filed Aug 12, 2026 |
| Aug 5, 2026 | Planned (10b5-1) | Christopher D. Brown (Director) sold 20,000 shares at about $8.49 ($170K), marked as a 10b5-1 plan trade. Holdings down 2% to 823,359 shares. | SEC filing Filed Aug 7, 2026 |
| Aug 4, 2026 | Sale | AWM Investment Company, Inc. (10% owner) sold 50,000 shares indirectly (by entity) at about $8.36 ($418K). Holdings by entity down 1% to 4,829,773 shares. Not marked as a 10b5-1 plan trade. | SEC filing Filed Aug 6, 2026 |
| Jul 2, 2026 | Planned (10b5-1) | Christopher D. Brown (Director) sold 2,200 shares at about $9.02 ($20K), marked as a 10b5-1 plan trade. Holdings down <1% to 843,359 shares. | SEC filing Filed Jul 7, 2026 |
| Jul 2, 2026 | Planned (10b5-1) | Kevin J. Knopp (CEO and Director) sold 222 shares at about $9.07 ($2K), marked as a 10b5-1 plan trade. Holdings down <1% to 732,603 shares. | SEC filing Filed Jul 7, 2026 |
| Jun 30, 2026 | Planned (10b5-1) | Christopher D. Brown (Director) sold 20,000 shares at about $8.84 ($177K), marked as a 10b5-1 plan trade. Holdings down 2% to 845,559 shares. | SEC filing Filed Jul 2, 2026 |
| Jun 26, 2026 | Planned (10b5-1) | Kevin J. Knopp (CEO and Director) sold 2,798 shares at about $9.09 ($25K), marked as a 10b5-1 plan trade. Holdings down <1% to 732,825 shares. | SEC filing Filed Jun 30, 2026 |
| Jun 23, 2026 | Planned (10b5-1) | Christopher D. Brown (Director) sold 9,900 shares at about $9.04 ($89K), marked as a 10b5-1 plan trade. Holdings down 1% to 865,559 shares. | SEC filing Filed Jun 25, 2026 |
| Jun 23–25, 2026 | Planned (10b5-1) | Kevin J. Knopp (CEO and Director) sold 60,345 shares between Jun 23 and Jun 25 at about $9.12 ($551K), marked as a 10b5-1 plan trade. Holdings down 8% to 735,623 shares. | SEC filing Filed Jun 25, 2026 |
| Jun 22–23, 2026 | Sale | AWM Investment Company, Inc. (10% owner) sold 7,718 shares indirectly between Jun 22 and Jun 23 at about $8.99 ($69K). Indirect holdings down <1% to 4,879,773 shares. Not marked as a 10b5-1 plan trade. | SEC filing Filed Jun 24, 2026 |
| Jun 4, 2026 | Planned (10b5-1) | Christopher D. Brown (Director) sold 100 shares at $9.00 ($900), marked as a 10b5-1 plan trade. Holdings down <1% to 875,459 shares. | SEC filing Filed Jun 5, 2026 |
| Jun 3, 2026 | Planned (10b5-1) | Christopher D. Brown (Director) sold 20,000 shares at about $8.73 ($175K), marked as a 10b5-1 plan trade. Holdings down 2% to 875,559 shares. | SEC filing Filed Jun 4, 2026 |
| Jun 2–4, 2026 | Sale | AWM Investment Company, Inc. (10% owner) sold 42,282 shares indirectly (by entity) between Jun 2 and Jun 4 at about $8.97 ($379K). Holdings by entity down 1% to 4,887,491 shares. Not marked as a 10b5-1 plan trade. | SEC filing Filed Jun 4, 2026 |
| May 28, 2026 | Planned (10b5-1) | Christopher D. Brown (Director) sold 30,000 shares at $9.00 ($270K), marked as a 10b5-1 plan trade. Holdings down 3% to 895,559 shares. | SEC filing Filed May 29, 2026 |
| May 28, 2026 | Planned (10b5-1) | Joseph H. Griffith IV (CFO) sold 6,940 shares at $9.03 ($63K), marked as a 10b5-1 plan trade. Holdings down 5% to 132,956 shares. | SEC filing Filed May 29, 2026 |
| May 27–28, 2026 | Sale | AWM Investment Company, Inc. (10% owner) sold 186,942 shares indirectly (by entity) between May 27 and May 28 at about $8.62 ($1.6M). Holdings by entity down 4% to 4,929,773 shares. Not marked as a 10b5-1 plan trade. | SEC filing Filed May 29, 2026 |
| May 11, 2026 | Sale | AWM Investment Company, Inc. (10% owner) sold 5,000 shares indirectly (by entity) at about $8.25 ($41K). Holdings by entity down <1% to 5,116,715 shares. Not marked as a 10b5-1 plan trade. | SEC filing Filed May 13, 2026 |
| May 8, 2026 | Sale | John Kenneweg (SVP, Sales & Product Marketing) sold 18,255 shares at about $8.11 ($148K). Holdings down 24% to 57,784 shares. Not marked as a 10b5-1 plan trade. | SEC filing Filed May 11, 2026 |
| May 6–8, 2026 | Sale | AWM Investment Company, Inc. (10% owner) sold 78,209 shares indirectly (by entity) between May 6 and May 8 at about $8.08 ($632K). Holdings by entity down 2% to 5,121,715 shares. Not marked as a 10b5-1 plan trade. | SEC filing Filed May 8, 2026 |
| May 6, 2026 | Planned (10b5-1) | Christopher D. Brown (Director) sold 20,000 shares at about $7.23 ($145K), marked as a 10b5-1 plan trade. Holdings down 2% to 925,559 shares. | SEC filing Filed May 7, 2026 |
| Apr 10, 2026 | Planned (10b5-1) | Kevin J. McCallion (SVP, Products and Production) sold 2,693 shares at about $7.01 ($19K), marked as a 10b5-1 plan trade. Holdings down 6% to 44,925 shares. | SEC filing Filed Apr 14, 2026 |
| Apr 8–9, 2026 | Planned (10b5-1) | Kevin J. McCallion (SVP, Products and Production) sold 24,000 shares between Apr 8 and Apr 9 at about $7.05 ($169K), marked as a 10b5-1 plan trade. Holdings down 35% to 44,925 shares. | SEC filing Filed Apr 10, 2026 |
| Apr 8–10, 2026 | Planned (10b5-1) | Christopher D. Brown (Director) sold 40,000 shares between Apr 8 and Apr 10 at about $7.06 ($282K), marked as a 10b5-1 plan trade. Holdings down 4% to 945,559 shares. | SEC filing Filed Apr 10, 2026 |
| Mar 2, 2026 | Planned (10b5-1) Amended filing | Kevin J. McCallion (SVP, Products and Production) sold 7 shares at $7.00 ($49), marked as a 10b5-1 plan trade. Holdings down <1% to 44,925 shares. This amends a filing from Mar 4. | SEC filing Filed Mar 5, 2026 |
| Feb 2, 2026 | Sale | Kevin J. Knopp (CEO and Director) sold 34,764 shares at about $6.18 ($215K). Holdings down 4% to 795,968 shares. Not marked as a 10b5-1 plan trade. | SEC filing Filed Feb 3, 2026 |
| Feb 2, 2026 | Sale | Joseph H. Griffith IV (CFO) sold 23,175 shares at about $6.18 ($143K). Holdings down 14% to 139,896 shares. Not marked as a 10b5-1 plan trade. | SEC filing Filed Feb 3, 2026 |
22 routine transactions (such as grants, option exercises or tax withholding) are not listed.
Cluster buys
No cluster buys in the last 12 months.
Red flags
No red flags in the last 12 months.
Key events
No key events in the last 12 months.
8-K filings, last 12 months
No 8-K filings in the last 12 months.
Red flags are objective triggers only: the item or form filed, never an opinion.
Follow MASS in the Insider Ledger app
Get the appA plain-English brief of insider purchases, 8-Ks and red flags at the companies you pick. No account needed.