Mar 31, 2026 filings. Quarterly 13F reports arrive up to 45 days after quarter end; this register is filed through May 29, 2026.
1,277 institutional managers reported holding IDXX for the quarter ended Mar 31, 2026. Together they hold about 88% of shares outstanding; the top 10 hold 42%. 111 opened new positions; 194 closed out. Complete ranked register from SEC 13F filings.
| manager | shares | % out | value (Mar 31, 2026 close) | change | held since |
|---|---|---|---|---|---|
| Vanguard Group | 9.92M | 12.38% | $5.58B | unchanged | ≤2013 |
| BlackRock | 8.37M | 10.44% | $4.70B | trimmed -2% | ≤2013 |
| State Street | 3.67M | 4.58% | $2.06B | unchanged | ≤2013 |
| Geode Capital | 2.66M | 3.32% | $1.49B | added +3% | ≤2013 |
| Invesco | 1.68M | 2.09% | $943.0M | added +11.7% | ≤2013 |
| Bamco INC /NY/ | 1.63M | 2.04% | $917.6M | trimmed -9.2% | ≤2013 |
| BNY Mellon | 1.50M | 1.88% | $845.2M | trimmed -7.4% | ≤2013 |
| Fundsmith (focused) | 1.47M | 1.83% | $823.4M | trimmed -21.9% | 2015 Q1 |
| Morgan Stanley | 1.32M | 1.64% | $739.3M | trimmed -15.3% | ≤2013 |
| UBS | 1.18M | 1.47% | $661.2M | added +2.8% | ≤2013 |
| Blair William & CO/IL | 946.3k | 1.18% | $531.6M | trimmed -5.5% | ≤2013 |
| Northern Trust | 911.9k | 1.14% | $512.3M | trimmed -1.2% | ≤2013 |
| Principal Financial Group INC | 883.7k | 1.10% | $496.4M | trimmed -9% | ≤2013 |
| Arrowstreet Capital | 838.8k | 1.05% | $471.2M | added +52.4% | 2017 Q1 |
| Capital Research Global Investors | 781.3k | 0.97% | $438.9M | added +28.6% | 2023 Q4 |
| Wellington Management | 735.5k | 0.92% | $413.2M | trimmed -5.6% | 2018 Q3 |
| Goldman Sachs | 716.9k | 0.89% | $402.7M | trimmed -13.8% | ≤2013 |
| Polen Capital | 695.8k | 0.87% | $390.9M | trimmed -27.6% | 2025 Q2 |
| Franklin Resources | 662.6k | 0.83% | $372.2M | added +5.7% | 2014 Q3 |
| Legal & General Group PLC | 650.8k | 0.81% | $365.6M | trimmed -3% | 2013 Q4 |
| T. Rowe Price | 638.1k | 0.80% | $358.4M | trimmed -33% | ≤2013 |
| Amundi | 610.8k | 0.76% | $343.1M | trimmed -1.3% | 2017 Q4 |
| Charles Schwab Investment Management | 610.2k | 0.76% | $342.8M | added +3.4% | ≤2013 |
| American Century Companies INC | 599.9k | 0.75% | $337.0M | trimmed -4.6% | 2016 Q1 |
| Dimensional Fund Advisors | 573.3k | 0.71% | $322.1M | added +4.3% | ≤2013 |
| Capital Group (American Funds) | 497.9k | 0.62% | $279.7M | opened | 2026 Q1 |
| Bank OF America CORP /DE/ | 488.0k | 0.61% | $274.2M | unchanged | ≤2013 |
| Fundsmith Investment Services LTD. (focused) | 481.6k | 0.60% | $270.5M | trimmed -13% | 2022 Q1 |
| Nuveen | 445.8k | 0.56% | $250.4M | trimmed -4.4% | ≤2013 |
| AustralianSuper Pty LTD | 443.0k | 0.55% | $248.9M | added +47.6% | 2025 Q2 |
| Capital Counsel LLC/NY | 420.2k | 0.52% | $236.1M | trimmed -1.6% | ≤2013 |
| Nomura Asset Management International INC. | 399.4k | 0.50% | $224.4M | trimmed -11.1% | 2023 Q4 |
| Royal Bank OF Canada | 391.7k | 0.49% | $220.0M | trimmed -1.7% | ≤2013 |
| Deutsche Bank AG\ | 388.8k | 0.48% | $218.4M | added +8.7% | 2013 Q3 |
| Cibc Bancorp USA INC. | 367.5k | 0.46% | $206.5M | trimmed -9.5% | 2017 Q1 |
| William Blair Investment Management, LLC | 351.6k | 0.44% | $197.5M | trimmed -20.3% | 2015 Q3 |
| Neuberger Berman Group LLC | 349.7k | 0.44% | $196.5M | added +27.3% | ≤2013 |
| Montrusco Bolton Investments INC. | 342.1k | 0.43% | $192.2M | added +93.4% | 2025 Q1 |
| Bessemer Group INC | 319.3k | 0.40% | $179.4M | added +2.5% | ≤2013 |
| Clearbridge Investments, LLC | 308.5k | 0.39% | $173.3M | added +5.3% | 2017 Q4 |
| Pictet Asset Management Holding SA | 287.9k | 0.36% | $161.8M | added +67.2% | 2016 Q2 |
| FMR (Fidelity) | 283.0k | 0.35% | $159.0M | added +12.6% | ≤2013 |
| Mitsubishi UFJ Asset Management CO., LTD. | 274.4k | 0.34% | $154.1M | added +6.9% | 2016 Q2 |
| Raymond James Financial INC | 273.0k | 0.34% | $153.3M | added +6.5% | 2015 Q1 |
| Williams Jones Wealth Management, LLC. | 263.5k | 0.33% | $148.0M | trimmed -1.6% | 2019 Q3 |
| Caisse de depot et placement du Quebec | 263.1k | 0.33% | $147.8M | added +5.8% | 2016 Q2 |
| Railway Pension Investments LTD | 256.5k | 0.32% | $144.1M | trimmed -21.3% | 2023 Q2 |
| BNP Paribas Financial Markets | 252.3k | 0.32% | $141.7M | trimmed -22.1% | 2014 Q1 |
| TD Asset Management INC | 236.5k | 0.29% | $132.9M | trimmed -11.7% | ≤2013 |
| First Trust Advisors LP | 234.7k | 0.29% | $131.8M | trimmed -0.6% | ≤2013 |
Largest 50 of 1,277 shown; the full ranked, searchable register is at boothcheck.com/holders/IDXX. Related filers are grouped using the filings' own included-manager declarations. Historically, several managers opening new positions in the same quarter said almost nothing about the quarter that followed (59,118 cases since 2013). A filed record, not a forecast. Nothing here is investment advice.