William Blair Investment Management
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William Blair Investment Management’s Idexx Laboratories IDXX Stock Holding History

William Blair Investment Management’s Portfolio IDXX Stock Details IDXX Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2026
Q1 		$198M Sell
351,621
-89,703
-20% -$57.5M 0.65% 28
2025
Q4 		$299M Sell
441,324
-17,695
-4% -$12.1M 0.83% 16
2025
Q3 		$293M Sell
459,019
-226,069
-33% -$137M 0.76% 23
2025
Q2 		$367M Buy
685,088
+47,977
+8% +$22.9M 0.98% 15
2025
Q1 		$268M Buy
637,111
+214,978
+51% +$93.3M 0.75% 27
2024
Q4 		$175M Buy
422,133
+369,471
+702% +$162M 0.43% 72
2024
Q3 		$26.6M Sell
52,662
-14,459
-22% -$7.02M 0.07% 266
2024
Q2 		$32.7M Sell
67,121
-1,907
-3% -$957K 0.09% 203
2024
Q1 		$37.3M Buy
69,028
+699
+1% +$382K 0.1% 195
2023
Q4 		$37.9M Buy
68,329
+1,194
+2% +$561K 0.11% 179
2023
Q3 		$29.4M Sell
67,135
-7,906
-11% -$3.94M 0.1% 222
2023
Q2 		$37.7M Sell
75,041
-279
-0.4% -$134K 0.12% 174
2023
Q1 		$37.7M Sell
75,320
-2,379
-3% -$1.14M 0.13% 159
2022
Q4 		$31.7M Sell
77,699
-29,947
-28% -$11.6M 0.12% 185
2022
Q3 		$35.1M Sell
107,646
-2,956
-3% -$1.09M 0.14% 155
2022
Q2 		$38.8M Sell
110,602
-5,827
-5% -$2.38M 0.14% 159
2022
Q1 		$63.7M Sell
116,429
-7,559
-6% -$3.98M 0.19% 137
2021
Q4 		$81.6M Buy
123,988
+2,201
+2% +$1.38M 0.22% 119
2021
Q3 		$75.7M Sell
121,787
-1,395
-1% -$937K 0.21% 123
2021
Q2 		$77.8M Buy
123,182
+27,944
+29% +$15.4M 0.24% 122
2021
Q1 		$46.6M Sell
95,238
-14,203
-13% -$7.12M 0.15% 150
2020
Q4 		$54.7M Sell
109,441
-19,543
-15% -$8.74M 0.18% 126
2020
Q3 		$50.7M Sell
128,984
-15,201
-11% -$5.62M 0.2% 124
2020
Q2 		$47.6M Sell
144,185
-22,715
-14% -$6.58M 0.19% 128
2020
Q1 		$40.4M Buy
166,900
+51,778
+45% +$13.5M 0.2% 127
2019
Q4 		$30.1M Sell
115,122
-42,745
-27% -$11.3M 0.12% 155
2019
Q3 		$42.9M Sell
157,867
-25,544
-14% -$7.11M 0.18% 127
2019
Q2 		$50.5M Buy
183,411
+61,078
+50% +$15M 0.21% 120
2019
Q1 		$27.4M Buy
122,333
+69,588
+132% +$14.4M 0.12% 160
2018
Q4 		$9.81M Sell
52,745
-97,236
-65% -$19.9M 0.05% 312
2018
Q3 		$37.4M Buy
149,981
+475
+0.3% +$115K 0.13% 176
2018
Q2 		$32.6M Sell
149,506
-122,779
-45% -$25.3M 0.12% 180
2018
Q1 		$52.1M Sell
272,285
-456,440
-63% -$84.2M 0.2% 142
2017
Q4 		$114M Buy
728,725
+500,359
+219% +$78.8M 0.44% 79
2017
Q3 		$35.5M Sell
228,366
-215,105
-49% -$34M 0.13% 171
2017
Q2 		$71.6M Sell
443,471
-82,629
-16% -$13.4M 0.26% 115
2017
Q1 		$81.3M Sell
526,100
-191,939
-27% -$26.5M 0.31% 104
2016
Q4 		$84.2M Sell
718,039
-993,908
-58% -$113M 0.34% 100
2016
Q3 		$193M Sell
1,711,947
-221,047
-11% -$23.3M 0.73% 42
2016
Q2 		$179M Sell
1,932,994
-627,528
-25% -$53.9M 0.71% 44
2016
Q1 		$201M Buy
2,560,522
+109,665
+4% +$7.9M 0.79% 40
2015
Q4 		$179M Buy
2,450,857
+218,502
+10% +$15.6M 0.72% 41
2015
Q3 		$166M Buy
+2,232,355
New +$160M 0.34% 87

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Geode Capital Management
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BAMCO Inc
BAMCO Inc New York $33.1B AUM 11.16% 1-Year Est. Return
Bank of New York Mellon
Bank of New York Mellon New York $544B AUM 28.31% 1-Year Est. Return
Fundsmith LLP
Fundsmith LLP London, United Kingdom $12.8B AUM 6.9% 1-Year Est. Return
Morgan Stanley
Morgan Stanley New York $1.66T AUM 25.57% 1-Year Est. Return

William Blair Investment Management's IDXX Position: Q1 2026 in Review

William Blair Investment Management reduced its Idexx Laboratories (IDXX) stake by 20% in Q1 2026, selling an estimated $57.5M and leaving 351,621 shares worth $198M. The position accounts for 0.65% of the portfolio, ranked #28.

William Blair Investment Management first reported a position in IDXX in Q3 2015 and has held it in 43 quarters since. The position peaked at $367M in Q2 2025. 1,312 funds tracked by Wall St. Rank hold IDXX as of Q1 2026.

  • William Blair Investment Management held 351,621 shares of Idexx Laboratories worth $198M as of Q1 2026.
  • William Blair Investment Management sold 89,703 Idexx Laboratories shares in Q1 2026, an estimated $57.5M.
  • Idexx Laboratories made up 0.65% of William Blair Investment Management's portfolio in Q1 2026, its #28 holding.
  • William Blair Investment Management first reported a position in Idexx Laboratories in Q3 2015 and has held it in 43 quarters since.
  • William Blair Investment Management's Idexx Laboratories position peaked at $367M in Q2 2025.
  • 1,312 funds tracked by Wall St. Rank held Idexx Laboratories as of Q1 2026.

Based on William Blair Investment Management's 13F filing for Q1 2026, filed 8 May 2026.