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← Back to 13F holdingsStock detail · v1

BIOGEN INC

$BIIB
Last close: $184.38(2026-04-24)BRK current position: 643,022 shares ($0.18B as of 2021-03-31)Quarters with activity: 2CUSIP: 09062X103

Price history with Berkshire transactions

InitiatedAddedTrimmedExited
BIIBS&P 500 (right axis, $)Shares held (right axis)
$100$200$300$400201820192020202120222023202420252026$179$319$459$599$7390162K324K486K648KINIT

Hover for daily price. Triangle markers show quarter-end Berkshire buy (▲ green) / sell (▼ orange/red) events from 13F-HR filings. Quarter-level granularity only — actual trade dates are not disclosed.

Berkshire's quarterly position history

QuarterSharesΔ SharesActionValue (USD)13F
2021-03-31643,022—held$179.9MView
2020-12-31643,022—held$157.5MView
2020-09-30643,022—held$182.4MView
2020-06-30643,022—held$172MView
2020-03-31643,022-5,425trimmed$203.4MView
2019-12-31648,447+648,447initiated$192.4MView

Prices via Yahoo Finance. Berkshire position data from quarterly 13F-HR filings. 13F has a ~45-day filing lag and only covers long US-listed equity positions. Cost basis below is approximated from the quarter-end value at which shares were added (FIFO).