Primecap Management
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Primecap Management’s Biogen BIIB Stock Holding History

Quarter Market Value Status Shares Shares
Change %
Trade Value Portfolio Weight Portfolio Position
2025
Q2
$1.98B Sell
15,802,122
-141,137
-0.9% -$17.7M 1.57% 15
2025
Q1
$2.18B Sell
15,943,259
-102,950
-0.6% -$14.1M 1.8% 14
2024
Q4
$2.45B Sell
16,046,209
-268,870
-2% -$41.1M 1.9% 13
2024
Q3
$3.16B Sell
16,315,079
-23,215
-0.1% -$4.5M 2.33% 9
2024
Q2
$3.79B Buy
16,338,294
+117,578
+0.7% +$27.3M 2.74% 7
2024
Q1
$3.5B Sell
16,220,716
-43,765
-0.3% -$9.44M 2.61% 7
2023
Q4
$4.21B Buy
16,264,481
+251,915
+2% +$65.2M 3.33% 2
2023
Q3
$4.12B Sell
16,012,566
-13,310
-0.1% -$3.42M 3.47% 2
2023
Q2
$4.56B Buy
16,025,876
+24,710
+0.2% +$7.04M 3.81% 2
2023
Q1
$4.45B Buy
16,001,166
+300,590
+2% +$83.6M 3.88% 2
2022
Q4
$4.35B Sell
15,700,576
-41,139
-0.3% -$11.4M 3.98% 2
2022
Q3
$4.2B Buy
15,741,715
+15,189
+0.1% +$4.06M 4.07% 2
2022
Q2
$3.21B Sell
15,726,526
-108,080
-0.7% -$22M 2.87% 4
2022
Q1
$3.33B Buy
15,834,606
+77,201
+0.5% +$16.3M 2.52% 5
2021
Q4
$3.78B Sell
15,757,405
-501,510
-3% -$120M 2.62% 4
2021
Q3
$4.6B Sell
16,258,915
-199,591
-1% -$56.5M 3.25% 3
2021
Q2
$5.7B Sell
16,458,506
-299,750
-2% -$104M 3.83% 2
2021
Q1
$4.69B Buy
16,758,256
+936,190
+6% +$262M 3.27% 2
2020
Q4
$3.87B Buy
15,822,066
+125,362
+0.8% +$30.7M 2.88% 5
2020
Q3
$4.45B Buy
15,696,704
+64,772
+0.4% +$18.4M 3.67% 4
2020
Q2
$4.18B Sell
15,631,932
-334,057
-2% -$89.4M 3.59% 5
2020
Q1
$5.05B Buy
15,965,989
+776,508
+5% +$246M 4.95% 2
2019
Q4
$4.51B Buy
15,189,481
+929,469
+7% +$276M 3.27% 4
2019
Q3
$3.32B Sell
14,260,012
-293,990
-2% -$68.4M 2.66% 7
2019
Q2
$3.4B Sell
14,554,002
-32,380
-0.2% -$7.57M 2.52% 7
2019
Q1
$3.45B Sell
14,586,382
-129,835
-0.9% -$30.7M 2.54% 7
2018
Q4
$4.43B Sell
14,716,217
-157,579
-1% -$47.4M 3.59% 3
2018
Q3
$5.26B Sell
14,873,796
-48,140
-0.3% -$17M 3.55% 3
2018
Q2
$4.33B Sell
14,921,936
-31,295
-0.2% -$9.08M 3.21% 3
2018
Q1
$4.09B Sell
14,953,231
-156,000
-1% -$42.7M 3.07% 3
2017
Q4
$4.81B Sell
15,109,231
-103,683
-0.7% -$33M 3.69% 1
2017
Q3
$4.76B Sell
15,212,914
-178,487
-1% -$55.9M 3.94% 1
2017
Q2
$4.18B Sell
15,391,401
-86,023
-0.6% -$23.3M 3.59% 3
2017
Q1
$4.23B Sell
15,477,424
-106,963
-0.7% -$29.2M 3.84% 2
2016
Q4
$4.42B Sell
15,584,387
-109,518
-0.7% -$31.1M 4.35% 1
2016
Q3
$4.91B Sell
15,693,905
-330,956
-2% -$104M 4.9% 1
2016
Q2
$3.88B Sell
16,024,861
-221,865
-1% -$53.7M 4.13% 3
2016
Q1
$4.23B Buy
16,246,726
+436,101
+3% +$114M 4.39% 2
2015
Q4
$4.84B Sell
15,810,625
-32,835
-0.2% -$10.1M 4.95% 2
2015
Q3
$4.62B Sell
15,843,460
-658,081
-4% -$192M 5.13% 2
2015
Q2
$6.67B Sell
16,501,541
-57,222
-0.3% -$23.1M 6.56% 1
2015
Q1
$6.99B Sell
16,558,763
-611,930
-4% -$258M 6.83% 1
2014
Q4
$5.83B Sell
17,170,693
-45,938
-0.3% -$15.6M 5.91% 1
2014
Q3
$5.7B Sell
17,216,631
-41,680
-0.2% -$13.8M 6.09% 1
2014
Q2
$5.44B Sell
17,258,311
-243,795
-1% -$76.9M 5.96% 1
2014
Q1
$5.35B Sell
17,502,106
-275,496
-2% -$84.3M 6.06% 1
2013
Q4
$4.97B Sell
17,777,602
-190,570
-1% -$53.3M 5.97% 1
2013
Q3
$4.33B Sell
17,968,172
-278,637
-2% -$67.1M 5.69% 1
2013
Q2
$3.93B Buy
+18,246,809
New +$3.93B 5.62% 1