William Blair & Company
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William Blair & Company’s Illumina ILMN Stock Holding History

William Blair & Company’s Portfolio ILMN Stock Details ILMN Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2026
Q1 		$230K Buy
1,867
+286
+18% +$37.6K ﹤0.01% 1428
2025
Q4 		$207K Sell
1,581
-1,421
-47% -$167K ﹤0.01% 1451
2025
Q3 		$285K Buy
3,002
+416
+16% +$41.3K ﹤0.01% 1320
2025
Q2 		$247K Buy
+2,586
New +$210K ﹤0.01% 1337
2025
Q1 		– Sell
-22,332
Closed -$2.98M – 1836
2024
Q4 		$2.98M Sell
22,332
-1,845
-8% -$263K 0.01% 621
2024
Q3 		$3.15M Sell
24,177
-804
-3% -$99.2K 0.01% 605
2024
Q2 		$2.61M Sell
24,981
-1,881
-7% -$211K 0.01% 637
2024
Q1 		$3.59M Sell
26,862
-408
-1% -$54.7K 0.01% 552
2023
Q4 		$3.69M Sell
27,270
-2,358
-8% -$272K 0.01% 528
2023
Q3 		$3.96M Sell
29,628
-3,698
-11% -$608K 0.02% 493
2023
Q2 		$6.08M Sell
33,326
-3,097
-9% -$627K 0.02% 405
2023
Q1 		$8.24M Sell
36,423
-2,981
-8% -$610K 0.03% 341
2022
Q4 		$7.75M Buy
39,404
+1,220
+3% +$253K 0.03% 336
2022
Q3 		$7.09M Sell
38,184
-2,402
-6% -$475K 0.03% 343
2022
Q2 		$7.28M Sell
40,586
-2,392
-6% -$611K 0.03% 342
2022
Q1 		$14.6M Sell
42,978
-3,782
-8% -$1.28M 0.05% 269
2021
Q4 		$17.3M Buy
46,760
+581
+1% +$220K 0.05% 252
2021
Q3 		$18.2M Buy
46,179
+223
+0.5% +$103K 0.06% 239
2021
Q2 		$21.2M Sell
45,956
-471
-1% -$190K 0.07% 219
2021
Q1 		$17.3M Buy
46,427
+2,934
+7% +$1.2M 0.07% 231
2020
Q4 		$15.7M Sell
43,493
-422
-1% -$135K 0.06% 238
2020
Q3 		$13.2M Sell
43,915
-5,563
-11% -$1.92M 0.06% 235
2020
Q2 		$17.8M Buy
49,478
+1,619
+3% +$521K 0.09% 194
2020
Q1 		$12.7M Sell
47,859
-1,761
-4% -$492K 0.08% 201
2019
Q4 		$16M Sell
49,620
-469
-0.9% -$142K 0.08% 209
2019
Q3 		$14.8M Sell
50,089
-4,480
-8% -$1.32M 0.09% 207
2019
Q2 		$19.5M Sell
54,569
-22,645
-29% -$7.15M 0.11% 173
2019
Q1 		$23.3M Buy
77,214
+5,663
+8% +$1.65M 0.14% 148
2018
Q4 		$20.9M Sell
71,551
-1,485
-2% -$460K 0.15% 141
2018
Q3 		$26.1M Sell
73,036
-9,128
-11% -$2.93M 0.16% 141
2018
Q2 		$22.3M Buy
82,164
+10,003
+14% +$2.54M 0.15% 145
2018
Q1 		$16.6M Sell
72,161
-4,451
-6% -$1.02M 0.12% 171
2017
Q4 		$16.3M Buy
76,612
+2,111
+3% +$434K 0.11% 187
2017
Q3 		$14.4M Buy
74,501
+16,801
+29% +$3.13M 0.11% 191
2017
Q2 		$9.74M Buy
57,700
+1,358
+2% +$235K 0.07% 242
2017
Q1 		$9.3M Sell
56,342
-9,742
-15% -$1.53M 0.08% 236
2016
Q4 		$8.23M Sell
66,084
-63,212
-49% -$8.52M 0.07% 236
2016
Q3 		$22.8M Buy
129,296
+7,242
+6% +$1.16M 0.2% 127
2016
Q2 		$16.7M Buy
122,054
+38,994
+47% +$5.54M 0.16% 159
2016
Q1 		$13.1M Buy
83,060
+4,295
+5% +$657K 0.12% 176
2015
Q4 		$14.7M Sell
78,765
-68,480
-47% -$11.1M 0.14% 165
2015
Q3 		$25.2M Buy
147,245
+1,686
+1% +$341K 0.22% 120
2015
Q2 		$30.9M Buy
145,559
+3,238
+2% +$632K 0.05% 459
2015
Q1 		$25.7M Buy
142,321
+290
+0.2% +$54.6K 0.04% 501
2014
Q4 		$25.5M Buy
142,031
+3,431
+2% +$605K 0.04% 515
2014
Q3 		$22.1M Buy
138,600
+6,164
+5% +$1.03M 0.04% 545
2014
Q2 		$23M Sell
132,436
-869
-0.7% -$130K 0.04% 527
2014
Q1 		$19.3M Buy
133,305
+61,366
+85% +$9.02M 0.03% 562
2013
Q4 		$7.74M Sell
71,939
-170
-0.2% -$15.6K 0.01% 845
2013
Q3 		$5.67M Sell
72,109
-386
-0.5% -$29.5K 0.01% 868
2013
Q2 		$5.28M Buy
+72,495
New +$4.64M 0.01% 865

Other funds holding ILMN

BlackRock
BlackRock New York $5.72T AUM 30.48% 1-Year Est. Return
Capital World Investors
Capital World Investors Los Angeles, California $733B AUM 35.63% 1-Year Est. Return
VPM
Vanguard Portfolio Management Malvern, Pennsylvania $1.91T AUM
VCM
Vanguard Capital Management Malvern, Pennsylvania $4.04T AUM
State Street
State Street Boston, Massachusetts $2.9T AUM 29.55% 1-Year Est. Return
WCM Investment Management
WCM Investment Management Laguna Beach, California $43.8B AUM 42.28% 1-Year Est. Return
AQR Capital Management
AQR Capital Management Greenwich, Connecticut $218B AUM 29.41% 1-Year Est. Return
CM
Corvex Management New York $2.52B AUM 25.53% 1-Year Est. Return
SC
Sessa Capital New York $5.51B AUM 47.23% 1-Year Est. Return
Geode Capital Management
Geode Capital Management Boston, Massachusetts $1.61T AUM 30.72% 1-Year Est. Return

William Blair & Company's ILMN Position: Q1 2026 in Review

William Blair & Company increased its Illumina (ILMN) stake by 18% in Q1 2026, buying an estimated $37.6K and bringing the position to 1,867 shares worth $230K. The position accounts for ﹤0.01% of the portfolio, ranked #1428.

William Blair & Company first reported a position in ILMN in Q2 2013 and has held it in 51 quarters since. The position peaked at $30.9M in Q2 2015. 845 funds tracked by Wall St. Rank hold ILMN as of Q1 2026.

  • William Blair & Company held 1,867 shares of Illumina worth $230K as of Q1 2026.
  • William Blair & Company bought 286 Illumina shares in Q1 2026, an estimated $37.6K.
  • Illumina made up ﹤0.01% of William Blair & Company's portfolio in Q1 2026, its #1428 holding.
  • William Blair & Company first reported a position in Illumina in Q2 2013 and has held it in 51 quarters since.
  • William Blair & Company's Illumina position peaked at $30.9M in Q2 2015.
  • 845 funds tracked by Wall St. Rank held Illumina as of Q1 2026.

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