IDEXX LABORATORIES INC (IDXX) Stock Institutional Trading Activity
IDEXX LABORATORIES INC (IDXX) position changes reported by tracked institutional filers across multiple SEC 13F reporting periods. Based on recent SEC 13F filings (Q4 2025), investors with some of the largest reported share count changes include Fundsmith, Polen Capital Management, Jensen Investment Management, Mairs & Power Growth Fund, and Fundsmith Investment Services. Explore insights into buying and selling patterns, position changes, and investment conviction levels to understand institutional trading behavior and market dynamics.
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- IDEXX LABORATORIES INC (IDXX) stock institutional ownership
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| Portfolio quarter | Name | Type | Quantity | Remaining | Reported stock balance |
|---|---|---|---|---|---|
| Q3 2018 | Fundsmith | Sell | -2,461 | 4,426,643 | $1,105,156 |
| Q3 2018 | Sequoia Fund | Sell | -197 | 1,592 | $397 |
| Q3 2018 | Renaissance Technologies LLC | Sell | -310,900 | 1,778,004 | $443,896 |
| Q2 2018 | Fundsmith | Buy | 1,447 | 4,429,104 | $965,278 |
| Q2 2018 | Sequoia Fund | Buy | 446 | 1,789 | $390 |
| Q1 2018 | Torray Fund | Buy | 1,200 | 1,200 | $230 |
| Q1 2018 | Fundsmith | Buy | 22,901 | 4,427,657 | $847,410 |
| Q1 2018 | Sequoia Fund | Buy | 1,343 | 1,343 | $254 |
| Q1 2018 | Renaissance Technologies LLC | Buy | 209,100 | 2,088,904 | $399,795 |
| Q4 2017 | Fundsmith | Sell | -39,952 | 4,404,756 | $688,816 |
| Q4 2017 | Mairs & Power Growth Fund | Sell | -300 | 4,298 | $672 |
| Q4 2017 | Renaissance Technologies LLC | Buy | 290,004 | 1,879,804 | $293,964 |
| Q3 2017 | Renaissance Technologies LLC | Buy | 237,900 | 1,589,800 | $247,198 |
| Q3 2017 | Fundsmith | Sell | -9,603,502 | 4,444,708 | $686,218 |
| Q3 2017 | Fundsmith | Buy | 9,602,170 | 14,048,210 | $897,962 |
| Q2 2017 | Renaissance Technologies LLC | Buy | 376,300 | 1,351,900 | $218,224 |
| Q2 2017 | Fundsmith | Sell | -34,167 | 4,446,040 | $717,680 |
| Q1 2017 | Mairs & Power Growth Fund | Buy | 600 | 4,598 | $711 |
| Q1 2017 | Renaissance Technologies LLC | Buy | 362,400 | 975,600 | $150,838 |
| Q1 2017 | Fundsmith | Buy | 3,341 | 4,480,207 | $692,685 |
| Q4 2016 | Renaissance Technologies LLC | Sell | -81,104 | 613,200 | $71,910 |
| Q4 2016 | Fundsmith | Sell | -14,017 | 4,476,866 | $528,629 |
| Q3 2016 | Renaissance Technologies LLC | Buy | 156,900 | 694,304 | $78,269 |
| Q3 2016 | Fundsmith | Buy | 21,547 | 4,490,883 | $506,257 |
| Q2 2016 | Renaissance Technologies LLC | Buy | 99,900 | 537,404 | $49,903 |
| Q2 2016 | Fundsmith | Buy | 258,657 | 4,469,336 | $415,023 |
| Q1 2016 | Renaissance Technologies LLC | Buy | 309,804 | 437,504 | $34,265 |
| Q1 2016 | Fundsmith | Buy | 1,719,511 | 4,210,679 | $329,780 |
| Q4 2015 | Renaissance Technologies LLC | Buy | 94,600 | 127,700 | $9,312 |
| Q4 2015 | Fundsmith | Buy | 1,610,682 | 2,491,168 | $181,656 |
Frequently asked questions about IDXX activity
Which institutional owners are buying IDXX?
Institutional owners buying IDXX include investors who have either initiated new positions or increased their existing holdings based on recent SEC 13F filings. The activity table above highlights which funds added shares in the latest reporting periods and how their positions changed over time.
What does "buy" mean in IDXX activity?
"Buy" means an investor increased their reported position in IDXX compared to the prior reporting period. This reflects growing exposure to IDEXX LABORATORIES INC (IDXX) rather than necessarily a brand-new position (though new positions also appear as buys when prior quantity was zero).
Is institutional interest in IDXX increasing?
Institutional interest in IDXX can be assessed by comparing the number of tracked funds adding or increasing positions versus those trimming or exiting across the periods shown. A higher number of additions typically signals increasing participation among large filers, but it should be read alongside position sizes and the full table.