BIOGEN INC

Ticker: BIIB CUSIP: 09062X103 Class: COM

DRIEHAUS CAPITAL MANAGEMENT LLC's Holding History (CIK: 0000938206)

Note: Option positions (PUT/CALL) are excluded.

Q2 2014

Shares 20,922 Value ($000) $6,597 Avg Close $300.97 Range $272.02 - $322.25

Q1 2014

Shares 37,258 Value ($000) $11,396 Avg Close $317.43 Range $270.62 - $358.89

Q4 2013

Shares 33,658 Value ($000) $9,416 Avg Close $258.65 Range $221.07 - $298.82

Q3 2013

Shares 28,125 Value ($000) $6,771 Avg Close $223.81 Range $203.55 - $248.95

Q2 2013

Shares 47,041 Value ($000) $10,123 Avg Close $213.68 Range $191.80 - $242.64

Period	Shares	Value ($000)	Average Close	Price Range
Q2 2014	20,922	$6,597	$300.97	$272.02 - $322.25
Q1 2014	37,258	$11,396	$317.43	$270.62 - $358.89
Q4 2013	33,658	$9,416	$258.65	$221.07 - $298.82
Q3 2013	28,125	$6,771	$223.81	$203.55 - $248.95
Q2 2013	47,041	$10,123	$213.68	$191.80 - $242.64