QTRX
Quanterix Corp
2.90$
+4.9%
vs. previous close
Closing price · As of: Nov 6, 2026
Ownership
Ownership Structure
Who owns Quanterix Corp (QTRX)? This page shows the largest institutions and funds, the ownership structure and the latest insider transactions. 80.3% of the shares are freely tradable; institutional investors hold 85.5%.
Institutional ownership
?Share of the stock held by institutional investors (funds, banks, insurers) according to regulatory filings.
85.5%
Insiders
?Share of the stock held by the executives, founders and major shareholders of the company itself.
6.3%
Float
?Share of stock freely tradable on the market — not locked up in the hands of founders, insiders, or major shareholders.
80.3%
Short % of float
?Shares sold short as a percentage of the freely tradable float — high values signal many bets on falling prices.
11.1%
Shares Outstanding
?Total number of shares issued. Price times share count gives market cap.
47Mio.
Largest Shareholders
Institutions
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| Arnhold & S. Bleichroeder Advisers, LLC | 11.64 | 5,506,330 | +323.5 | 06/30/2026 |
| BlackRock Inc | 7.69 | 3,635,411 | +10.9 | 06/30/2026 |
| Blue Water Life Science Advisors, LLC | 7.35 | 3,474,202 | +62.2 | 06/30/2026 |
| Portolan Capital Management, LLC | 4.02 | 1,899,308 | -35.5 | 06/30/2026 |
| Vanguard Capital Management, LLC | 3.81 | 1,800,644 | +0.9 | 06/30/2026 |
| Lionhunter Capital Management, LLC | 3.17 | 1,500,427 | +0.0 | 06/30/2026 |
| AQR Capital Management LLC | 2.84 | 1,343,005 | +1,496.3 | 06/30/2026 |
Funds
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| First Eagle Small Cap Opportunity I | 4.05 | 1,917,543 | -10.2 | 09/30/2026 |
| Strategic Advisers U.S. Total Stock | 3.05 | 1,441,800 | +0.0 | 08/31/2026 |
| Vanguard MStar Total Stk Mkt Idx Invest | 2.65 | 1,254,850 | +0.0 | 09/30/2026 |
Largest reported positions according to regulatory filings; stake as a percentage of shares outstanding, change versus the previous filing. Source: fundamentals data.
Insider holdings
| Person | Role | Shares | Value | As of | Type |
|---|---|---|---|---|---|
| Donnelly William P | Director | 268,765 | 779,419 $ | Aug 13, 2026 | both |
| Miller Michael Francis | Chief Technology Officer | 39,543 | 114,675 $ | Oct 15, 2026 | direct |
| Mendel Scott | Director | 28,454 | 82,517 $ | Oct 1, 2026 | direct |
| Magovcevic-Liebisch Ivana | Director | 15,883 | 46,061 $ | Oct 2, 2026 | direct |
| Elliott Jeffrey Thomas | Director | 15,345 | 44,501 $ | Aug 19, 2026 | direct |
| Lai Goldman Myla | Director | 15,041 | 43,619 $ | Jul 8, 2026 | direct |
Holdings as of each person's most recent SEC Form 4 filing — excluding options and RSUs, which are not shares yet. Holdings may have changed between two filings.
Insiders
Insider Transactions
| Date | Person | Role | Type | Shares | Price | Value |
|---|---|---|---|---|---|---|
| Oct 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 249 | 3.07 | 764 |
| Oct 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 834 | – | – |
| Oct 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 111 | 3.07 | 341 |
| Oct 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 372 | – | – |
| Oct 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 135 | – | – |
| Oct 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 41 | 3.07 | 126 |
| Oct 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 136 | – | – |
| Oct 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 25 | 3.07 | 77 |
| Oct 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 81 | – | – |
| Oct 2, 2026 | Magovcevic-Liebisch Ivana | Director | Other | 4,224 | – | – |
| Oct 1, 2026 | Mendel Scott | Director | Other | 4,398 | 3.41 | 14,997 |
| Oct 1, 2026 | Donnelly William P | Director | Other | 6,964 | 3.41 | 23,747 |
| Sep 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 249 | 2.72 | 677 |
| Sep 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 834 | – | – |
| Sep 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 111 | 2.72 | 302 |
| Sep 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 372 | – | – |
| Sep 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 135 | – | – |
| Sep 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 41 | 2.72 | 112 |
| Sep 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 136 | – | – |
| Sep 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 25 | 2.72 | 68 |
| Sep 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 81 | – | – |
| Aug 31, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 48 | 2.67 | 128 |
| Aug 31, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 159 | – | – |
| Aug 19, 2026 | Elliott Jeffrey Thomas | Director | Other | 3,955 | – | – |
| Aug 17, 2026 | Donnelly William P | Director | Other | 2,802 | – | – |
| Aug 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 249 | 2.59 | 645 |
| Aug 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 834 | – | – |
| Aug 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 111 | 2.59 | 287 |
| Aug 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 372 | – | – |
| Aug 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 135 | – | – |
| Aug 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 41 | 2.59 | 106 |
| Aug 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 136 | – | – |
| Aug 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 25 | 2.59 | 65 |
| Aug 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 81 | – | – |
| Aug 13, 2026 | Donnelly William P | Director | Buy | 72,245 | 2.93 | 211,678 |
| Aug 12, 2026 | Donnelly William P | Director | Buy | 27,155 | 2.75 | 74,676 |
| Jul 31, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 39 | 3.48 | 136 |
| Jul 31, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 130 | – | – |
| Jul 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 249 | 4.24 | 1,056 |
| Jul 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 834 | – | – |
| Jul 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 111 | 4.24 | 471 |
| Jul 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 372 | – | – |
| Jul 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 135 | – | – |
| Jul 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 41 | 4.24 | 174 |
| Jul 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 136 | – | – |
| Jul 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 25 | 4.24 | 106 |
| Jul 15, 2026 | Miller Michael Francis | Chief Technology Officer | Other | 81 | – | – |
| Jul 8, 2026 | Mendel Scott | Director | Other | 8,073 | – | – |
| Jul 8, 2026 | Lai Goldman Myla | Director | Other | 8,073 | – | – |
Reportable transactions by officers and major shareholders from SEC Form 4 filings. "Other" includes things like stock grants and option exercises without a buy/sell character. View all insider transactions →
Data as of: November 6, 2026 · Source: fundamental data & SEC filings (annual and quarterly reports, 10-K/10-Q)
Note: pure fact-based analysis, not investment advice and not a solicitation to buy or sell. All figures without guarantee.