QTRX insider buying – Quanterix Corp
20 insider purchases since 2016 worth $18.5M by 11 different insiders. Last 12 months: 1 purchases, $286,354. Most recent filing: 2026-08-14.
Small company Public float $239M (latest 10-K, SEC). Share prices of small companies usually swing much more than those of large ones, in both directions, and are easier to move with little trading.
Same time range as the chart above - each mark sits under the week of the trade. Circles = purchases (height = price paid, size = amount), red triangles = open-market sales of $50k+. Prices as reported, not adjusted for later stock splits. 5 older purchases (before the 5-year window) are listed in the table below.
Purchases are open-market buys (SEC Form 4, code "P") - insiders paying with their own money. Sales are open-market sales (code "S") of $50,000 or more; many sales are pre-planned (Rule 10b5-1) or made for taxes and diversification. Each row links to the original filing.
Bought, sold, still holding?
| Insider | Bought | First / last buy | Sold since 2016 | Holds now* | Status |
|---|---|---|---|---|---|
| WALT DAVID R Director | $7.9M 6× · 821,064 sh | 2017-12-11 2025-06-12 | – | 1,872,890 shares as of 2026-01-06 | Holds - never sold |
| CRANDELL KEITH Director | $4.0M 1× · 266,000 sh | 2017-12-11 2017-12-11 | – | 131,236 shares as of 2023-04-04 | Holds - never sold |
| MEISTER PAUL M Director | $2.0M 1× · 234,304 sh | 2022-08-10 2022-08-10 | – | 313,253 shares as of 2026-01-15 | Holds - never sold |
| Toloue Masoud CEO | $1.6M 3× · 169,900 sh | 2022-08-12 2025-06-09 | 1× · $84,962 last 2022-06-13 | 507,310 shares as of 2026-01-20 | Holds (sold earlier) |
| DONNELLY WILLIAM P Director | $1.3M 3× · 212,713 sh | 2023-09-08 2026-08-12 | – | 162,401 shares as of 2026-08-19 | Holds - never sold |
| Madaus Martin D Director | $755,893 1× · 89,667 sh | 2022-08-10 2022-08-10 | 27× · $3.9M last 2020-11-04 | 291,541 shares as of 2025-01-06 | Holds (sold earlier) |
| HRUSOVSKY E KEVIN CEO | $510,000 1× · 34,000 sh | 2017-12-11 2017-12-11 | 78× · $15.2M last 2022-01-03 | 910,249 shares as of 2022-07-06 | Sold part |
| DOYLE MICHAEL A CFO | $308,850 1× · 30,000 sh | 2022-08-12 2022-08-12 | – | 88,332 shares as of 2023-10-02 | Holds - never sold |
| Hlavinka Sarah E. Director | $100,442 1× · 10,160 sh | 2022-08-11 2022-08-11 | – | 60,070 shares as of 2025-07-03 | Holds - never sold |
| Connolly John M Director | $49,626 1× · 2,700 sh | 2018-12-04 2018-12-04 | – | 9,510 shares as of 2020-01-06 | Holds - never sold |
| Sriram Vandana CFO | $19,878 1× · 4,150 sh | 2025-09-12 2025-09-12 | – | 31,598 shares as of 2026-06-23 | Holds - never sold |
* Shares held after the insider's most recent SEC filing for this company (all share classes, direct and indirect). If an insider stops filing, later changes are not known.
Insider buying and selling by year
| Year | Purchases | Bought | Buyers | Sales | Sold |
|---|---|---|---|---|---|
| 2026 | 1 | $286,354 | 1 | – | – |
| 2025 | 5 | $2.9M | 4 | – | – |
| 2024 | 2 | $831,730 | 2 | – | – |
| 2023 | 1 | $501,970 | 1 | – | – |
| 2022 | 6 | $5.6M | 6 | 5 | $537,570 |
| 2021 | 0 | – | – | 47 | $14.9M |
| 2020 | 1 | $900,706 | 1 | 72 | $10.3M |
| 2019 | 0 | – | – | 15 | $3.1M |
| 2018 | 1 | $49,626 | 1 | 13 | $3.4M |
| 2017 | 3 | $7.5M | 3 | – | – |
Insider purchases
| Filed | Insider | Role | Shares | Avg price | Value | Holdings | Filing |
|---|---|---|---|---|---|---|---|
| 2026-08-14 | DONNELLY WILLIAM P | Director | 99,400 | $2.88 | $286,354 | SEC | |
| 2025-09-17 | Sriram Vandana | CFO | 4,150 | $4.79 | $19,878 | +5.0% | SEC |
| 2025-06-13 | WALT DAVID R | Director | 160,000 | $6.16 | $985,641 | +9.4% | SEC |
| 2025-06-10 | Toloue Masoud | CEO | 45,900 | $5.42 | $248,778 | +9.7% | SEC |
| 2025-06-09 | WALT DAVID R | Director | 210,000 | $5.40 | $1.1M | +14.0% | SEC |
| 2025-06-09 | DONNELLY WILLIAM P | Director | 93,113 | $5.44 | $506,535 | +202.5% | SEC |
| 2024-09-17 | WALT DAVID R | Director | 47,000 | $13.29 | $624,630 | +3.3% | SEC |
| 2024-08-15 | Toloue Masoud | CEO | 19,000 | $10.90 | $207,100 | +5.7% | SEC |
| 2023-09-11 | DONNELLY WILLIAM P | Director | 20,200 | $24.85 | $501,970 | +245.2% | SEC |
| 2022-08-16 | Toloue Masoud | CEO | 105,000 | $10.43 | $1.1M | +129.9% | SEC |
| 2022-08-16 | DOYLE MICHAEL A | CFO | 30,000 | $10.29 | $308,850 | +161.2% | SEC |
| 2022-08-11 | Hlavinka Sarah E. | Director | 10,160 | $9.89 | $100,442 | +63.1% | SEC |
| 2022-08-10 | WALT DAVID R | Director | 150,000 | $8.62 | $1.3M | +11.7% | SEC |
| 2022-08-10 | Madaus Martin D | Director | 89,667 | $8.43 | $755,893 | +54.4% | SEC |
| 2022-08-10 | MEISTER PAUL M | Director | 234,304 | $8.53 | $2.0M | +1279.9% | SEC |
| 2020-03-17 | WALT DAVID R | Director | 54,064 | $16.66 | $900,706 | +4.4% | SEC |
| 2018-12-07 | Connolly John M | Director | 2,700 | $18.38 | $49,626 | +118.9% | SEC |
| 2017-12-13 | WALT DAVID R | Director | 200,000 | $15.00 | $3.0M | +19.7% | SEC |
| 2017-12-13 | HRUSOVSKY E KEVIN | CEO | 34,000 | $15.00 | $510,000 | +4.0% | SEC |
| 2017-12-13 | CRANDELL KEITH | Director | 266,000 | $15.00 | $4.0M | +20.9% | SEC |
Insider sales
| Filed | Insider | Role | Shares | Avg price | Value | Type | Filing |
|---|---|---|---|---|---|---|---|
| 2022-06-14 | Toloue Masoud | CEO | 5,564 | $15.27 | $84,962 | Sale | SEC |
| 2022-03-28 | Duffy David C. | Officer | 3,266 | $30.00 | $97,980 | Sale | SEC |
| 2022-02-04 | Duffy David C. | Officer | 3,266 | $30.91 | $100,952 | Sale | SEC |
| 2022-01-31 | Duffy David C. | Officer | 3,266 | $30.00 | $97,980 | Sale | SEC |
| 2022-01-05 | HRUSOVSKY E KEVIN | CEO | 3,715 | $41.91 | $155,696 | Sale | SEC |
| 2021-12-30 | Duffy David C. | Officer | 1,667 | $40.71 | $67,864 | Sale | SEC |
| 2021-12-03 | HRUSOVSKY E KEVIN | CEO | 3,710 | $40.29 | $149,462 | Sale | SEC |
| 2021-11-22 | Duffy David C. | Officer | 1,667 | $45.54 | $75,915 | Sale | SEC |
| 2021-11-10 | HRUSOVSKY E KEVIN | CEO | 5,000 | $55.18 | $275,902 | Sale | SEC |
| 2021-11-08 | Mattoon Dawn | Officer | 8,536 | $57.28 | $488,914 | Sale | SEC |
| 2021-11-04 | HRUSOVSKY E KEVIN | CEO | 3,505 | $52.61 | $184,386 | Sale | SEC |
| 2021-10-22 | HRUSOVSKY E KEVIN | CEO | 5,000 | $50.70 | $253,524 | Sale | SEC |
| 2021-10-19 | Duffy David C. | Officer | 1,667 | $51.47 | $85,800 | Sale | SEC |
| 2021-10-04 | HRUSOVSKY E KEVIN | CEO | 8,594 | $49.97 | $429,441 | Sale | SEC |
| 2021-10-04 | Duffy David C. | Officer | 1,667 | $47.72 | $79,549 | Sale | SEC |
Showing the latest 15 of 152 sales of $50,000+ since 2016.
Compiled automatically from public SEC filings. Not investment advice. Get every new insider purchase in the daily report.
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