Quanterix
Builds Simoa and spatial biology tools for ultra-sensitive biomarker research and diagnostics.
$2.58
After-hours close−0.06 (−2.34%)
At close$2.65(+0.21%)
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Breakdown13F · Form 4
Institutions 63.14%29.74M sharesInsiders 7.18%3.38M sharesOther 29.68%13.98M shares
Shares outstanding 47.11M · Float 38.46M · 81.6% free float
Institutions13F, as of Jun 30, 2026
136 holders · 29.74M shares · 38 new positions · 83 increased · 29 reduced · 31 closed
| Holder | Shares | % outstanding | Chg q/q | Filed |
|---|---|---|---|---|
| BlackRock, Inc. | 3.64M | 7.72% | +357.8K | Aug 7, 2026 |
| Blue Water Life Science Advisors, LP | 3.47M | 7.38% | +1.33M | Aug 14, 2026 |
| First Eagle Investment Management, LLC | 2.75M | 5.84% | +1.45M | Aug 24, 2026 |
| Portolan Capital Management, LLC | 1.90M | 4.03% | −1.05M | Aug 14, 2026 |
| Vanguard Capital Management LLC | 1.80M | 3.82% | +16.0K | Aug 13, 2026 |
| Lionhunter Capital Management, LLC | 1.50M | 3.19% | +1.50Mnew | Aug 13, 2026 |
| AQR Capital Management LLC | 1.34M | 2.85% | +1.26M | Aug 14, 2026 |
| Geode Capital Management, LLC | 1.13M | 2.40% | +136.6K | Aug 12, 2026 |
Beneficial owners13D/G · 5% or more, as filed
| Holder | % of class | Shares | Form | Filed |
|---|---|---|---|---|
| Ameriprise Financial, Inc. | 7.50% | 3.54M | 13G | May 15, 2026 ↗ |
| BlackRock, Inc. | 7.30% | 2.84M | 13G | Jul 17, 2025 ↗ |
| Portolan Capital Management, LLC | 6.25% | 2.95M | 13G | May 15, 2026 ↗ |
| Telegraph Hill Partners III, L.P. | 5.40% | 2.50M | 13G | Nov 19, 2025 ↗ |
InsidersForm 4
| Insider | Role | Shares | % outstanding | Filed |
|---|---|---|---|---|
| David R. Walt | director | 1.87M | 3.98% | Jan 6, 2026 |
| Masoud Toloue | director, officer: President & CEO | 507.3K | 1.08% | Jan 20, 2026 |
| Paul M. Meister | director | 313.3K | 0.66% | Jan 15, 2026 |
| William P. Donnelly | director | 261.8K | 0.56% | Aug 19, 2026 |
| Malcolm Garret Hampton | director | 70.1K | 0.15% | Jan 6, 2026 |
| Alan Bruce Sachs | director | 70.1K | 0.15% | Jan 6, 2026 |
| Sarah E. Hlavinka | director | 60.1K | 0.13% | Jul 3, 2025 |
| Karen Flynn | director | 57.2K | 0.12% | Jan 6, 2026 |
| Ivana Magovcevic-Liebisch | director | 43.6K | 0.09% | Jan 15, 2026 |
| Michael Francis Miller | officer: Chief Technology Officer | 37.3K | 0.08% | Aug 17, 2026 |
4 ten-percent owners hold 2.85M shares by Form 4, outside the officers-and-directors figure above · 21 people have not refiled in the last 18 months (1.55M shares), so they are not in the figure above
Latest trades
| Date | Insider | Type | Shares | Avg price | Owned after |
|---|---|---|---|---|---|
| Aug 13, 2026 | William P. Donnellydirector | Purchase | 72,245 | $2.93 | 99,400 |
| Aug 12, 2026 | William P. Donnellydirector | Purchase | 27,155 | $2.75 | 27,155 |
| May 12, 2026 | Benjamin Meadowsofficer: Chief Commercial Officer | Purchase | 3,500 | $2.77 | 3,500 |
| Sep 12, 2025 | Vandana Sriramofficer: Chief Financial Officer | Purchase | 4,150 | $4.79 | 87,200 |
CongressHouse and Senate disclosures
Not reported.