NASDAQ:BIIB | Historical Stock Price | BIOGEN INC.

Complete retained daily price history on its own workbook tab. Split-adjusted close keeps every historical share price on one comparable split basis. Cumulative dividend-reinvested close is the daily close of a rebased total-return index: it starts with one share at the earliest retained close, reinvests every distribution, and normalizes every forward and reverse split exactly once. Admitted exchange opening prices remain a distinct current-session series.

Available history
1991-09-17 to 2026-09-04
Data captured

Stock Price Chart

Blue: Split-adjusted close · Orange: Cumulative dividend-reinvested close

$0.34$1.42$6.01$25.38$107.26$453.211991-09-172026-08-27

Logarithmic scale. Both lines share the same starting value for the selected range.

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Historical Stock Price — 2009

DateSplit-adjusted closeCumulative dividend-reinvested closeReported volumeOpen priceExchange Volume
2009-12-31$53.50$53.501,680,400
2009-12-30$53.70$53.701,861,000
2009-12-29$53.40$53.402,020,000
2009-12-28$53.27$53.272,181,900
2009-12-24$52.24$52.24630,900
2009-12-23$52.16$52.163,345,000
2009-12-22$52.32$52.324,175,900
2009-12-21$51.09$51.093,636,100
2009-12-18$50.07$50.076,382,400
2009-12-17$49.45$49.453,977,200
2009-12-16$50.25$50.254,815,200
2009-12-15$49.43$49.433,072,800
2009-12-14$48.87$48.872,715,400
2009-12-11$48.65$48.652,581,500
2009-12-10$48.26$48.262,182,800
2009-12-09$48.17$48.172,942,600
2009-12-08$48.06$48.062,831,400
2009-12-07$48.30$48.302,471,600
2009-12-04$48.18$48.182,882,900
2009-12-03$47.38$47.382,436,800
2009-12-02$47.74$47.742,629,800
2009-12-01$47.84$47.842,296,700
2009-11-30$46.94$46.943,450,600
2009-11-27$46.92$46.921,476,200
2009-11-25$47.45$47.451,477,700
2009-11-24$47.38$47.383,118,800
2009-11-23$46.79$46.792,437,600
2009-11-20$46.38$46.382,829,100
2009-11-19$45.85$45.853,073,600
2009-11-18$46.16$46.162,593,800
2009-11-17$46.05$46.054,285,700
2009-11-16$46.53$46.535,304,900
2009-11-13$46.72$46.722,806,600
2009-11-12$46.50$46.503,910,200
2009-11-11$46.43$46.433,894,300
2009-11-10$45.51$45.514,664,700
2009-11-09$45.41$45.414,801,800
2009-11-06$45.76$45.768,636,900
2009-11-05$44.39$44.396,792,100
2009-11-04$42.80$42.805,209,500
2009-11-03$43.25$43.254,420,200
2009-11-02$42.59$42.594,535,300
2009-10-30$42.13$42.133,532,100
2009-10-29$43.08$43.085,338,600
2009-10-28$43.53$43.533,395,700
2009-10-27$44.55$44.554,735,200
2009-10-26$44.13$44.134,805,800
2009-10-23$43.81$43.8111,117,100
2009-10-22$47.23$47.233,647,200
2009-10-21$46.43$46.436,037,200
2009-10-20$48.06$48.065,792,300
2009-10-19$49.39$49.392,301,000
2009-10-16$49.20$49.203,509,800
2009-10-15$49.79$49.793,262,100
2009-10-14$50.04$50.043,249,900
2009-10-13$48.80$48.801,378,700
2009-10-12$48.69$48.691,592,300
2009-10-09$49.01$49.011,560,100
2009-10-08$48.60$48.601,871,900
2009-10-07$49.17$49.171,383,400
2009-10-06$49.02$49.021,967,700
2009-10-05$48.54$48.542,096,700
2009-10-02$48.89$48.892,453,200
2009-10-01$49.34$49.343,249,500
2009-09-30$50.52$50.523,463,300
2009-09-29$51.41$51.414,462,000
2009-09-28$50.57$50.571,407,800
2009-09-25$50.11$50.112,121,200
2009-09-24$50.23$50.231,682,200
2009-09-23$50.23$50.231,340,900
2009-09-22$50.53$50.531,829,400
2009-09-21$50.89$50.892,482,200
2009-09-18$50.00$50.003,794,800
2009-09-17$50.45$50.453,203,700
2009-09-16$51.55$51.552,481,500
2009-09-15$51.41$51.412,046,200
2009-09-14$50.83$50.832,294,100
2009-09-11$50.84$50.841,929,400
2009-09-10$50.33$50.332,538,700
2009-09-09$51.04$51.042,861,500
2009-09-08$51.18$51.182,888,800
2009-09-04$51.01$51.014,276,300
2009-09-03$49.91$49.912,371,600
2009-09-02$49.19$49.192,061,800
2009-09-01$49.24$49.243,144,400
2009-08-31$50.20$50.202,688,000
2009-08-28$49.93$49.931,952,300
2009-08-27$50.05$50.052,476,900
2009-08-26$49.92$49.921,916,400
2009-08-25$49.71$49.711,965,600
2009-08-24$49.53$49.531,692,900
2009-08-21$49.97$49.972,238,200
2009-08-20$49.57$49.571,777,300
2009-08-19$49.03$49.032,245,100
2009-08-18$48.35$48.351,981,400
2009-08-17$48.25$48.252,010,200
2009-08-14$48.78$48.782,125,500
2009-08-13$48.92$48.922,654,900
2009-08-12$49.00$49.003,684,400
2009-08-11$47.81$47.811,746,400
2009-08-10$47.93$47.931,929,400
2009-08-07$47.28$47.281,600,300
2009-08-06$46.65$46.652,779,000
2009-08-05$47.62$47.622,298,600
2009-08-04$48.61$48.611,675,200
2009-08-03$48.36$48.362,462,000
2009-07-31$47.55$47.552,568,600
2009-07-30$47.36$47.363,567,000
2009-07-29$48.12$48.123,228,100
2009-07-28$49.02$49.022,422,700
2009-07-27$49.21$49.212,140,300
2009-07-24$48.98$48.981,589,300
2009-07-23$48.59$48.593,743,300
2009-07-22$46.86$46.862,409,900
2009-07-21$47.76$47.762,763,100
2009-07-20$46.92$46.924,685,600
2009-07-17$46.07$46.073,379,300
2009-07-16$47.10$47.104,984,800
2009-07-15$46.67$46.673,611,400
2009-07-14$45.94$45.944,111,200
2009-07-13$46.16$46.163,634,000
2009-07-10$44.75$44.753,146,400
2009-07-09$45.43$45.432,509,200
2009-07-08$44.86$44.863,458,200
2009-07-07$44.49$44.492,638,100
2009-07-06$45.22$45.222,731,900
2009-07-02$45.00$45.005,113,000
2009-07-01$46.77$46.775,721,100
2009-06-30$45.15$45.158,872,800
2009-06-29$47.32$47.327,032,100
2009-06-26$50.07$50.072,281,900
2009-06-25$49.99$49.992,303,000
2009-06-24$49.23$49.232,412,600
2009-06-23$48.73$48.732,417,800
2009-06-22$49.10$49.104,710,100
2009-06-19$51.67$51.674,628,800
2009-06-18$51.99$51.991,704,100
2009-06-17$51.82$51.822,347,000
2009-06-16$50.89$50.892,247,700
2009-06-15$50.19$50.192,846,400
2009-06-12$51.38$51.381,826,600
2009-06-11$51.46$51.462,735,500
2009-06-10$51.62$51.622,058,100
2009-06-09$52.38$52.381,803,100
2009-06-08$51.83$51.831,856,300
2009-06-05$52.12$52.123,439,300
2009-06-04$53.15$53.152,822,600
2009-06-03$53.43$53.433,815,500
2009-06-02$52.32$52.323,177,500
2009-06-01$50.90$50.902,414,100
2009-05-29$51.79$51.792,073,000
2009-05-28$51.10$51.101,851,900
2009-05-27$50.98$50.982,656,300
2009-05-26$51.24$51.243,047,200
2009-05-22$50.39$50.391,285,500
2009-05-21$50.73$50.732,095,000
2009-05-20$51.64$51.643,029,300
2009-05-19$50.83$50.832,575,100
2009-05-18$50.70$50.702,652,800
2009-05-15$49.07$49.072,439,200
2009-05-14$49.00$49.002,634,100
2009-05-13$48.52$48.522,405,600
2009-05-12$49.20$49.202,888,700
2009-05-11$49.14$49.142,430,700
2009-05-08$48.60$48.604,733,500
2009-05-07$47.20$47.204,087,200
2009-05-06$46.71$46.712,822,900
2009-05-05$46.43$46.431,789,500
2009-05-04$46.61$46.612,903,900
2009-05-01$46.26$46.263,139,500
2009-04-30$48.34$48.344,157,200
2009-04-29$47.42$47.424,216,900
2009-04-28$47.33$47.332,850,300
2009-04-27$46.13$46.133,141,400
2009-04-24$46.08$46.084,226,500
2009-04-23$45.98$45.983,254,400
2009-04-22$47.05$47.052,907,400
2009-04-21$47.55$47.552,955,700
2009-04-20$48.35$48.353,989,200
2009-04-17$50.09$50.094,393,100
2009-04-16$51.49$51.493,767,400
2009-04-15$51.18$51.183,366,200
2009-04-14$51.49$51.492,244,300
2009-04-13$52.52$52.521,821,500
2009-04-09$52.96$52.963,857,000
2009-04-08$53.64$53.646,906,000
2009-04-07$52.09$52.099,833,200
2009-04-06$49.63$49.632,328,300
2009-04-03$50.32$50.322,794,600
2009-04-02$52.20$52.202,767,900
2009-04-01$51.88$51.882,904,600
2009-03-31$52.42$52.423,236,200
2009-03-30$52.54$52.544,321,100
2009-03-27$52.28$52.283,642,700
2009-03-26$52.66$52.664,395,700
2009-03-25$51.52$51.523,320,700
2009-03-24$50.85$50.852,608,000
2009-03-23$51.50$51.503,294,400
2009-03-20$49.97$49.974,952,900
2009-03-19$50.62$50.622,880,700
2009-03-18$50.06$50.063,101,400
2009-03-17$49.63$49.633,677,100
2009-03-16$47.58$47.582,668,100
2009-03-13$48.50$48.502,546,700
2009-03-12$48.88$48.882,989,300
2009-03-11$46.09$46.093,730,900
2009-03-10$45.66$45.663,429,800
2009-03-09$43.83$43.833,983,000
2009-03-06$44.23$44.234,499,300
2009-03-05$43.64$43.643,332,900
2009-03-04$46.20$46.203,500,500
2009-03-03$44.61$44.613,045,900
2009-03-02$44.00$44.004,216,400
2009-02-27$46.04$46.045,631,100
2009-02-26$47.69$47.694,007,100
2009-02-25$50.55$50.554,318,800
2009-02-24$49.65$49.656,415,200
2009-02-23$49.38$49.384,099,400
2009-02-20$50.78$50.783,519,000
2009-02-19$50.76$50.762,137,100
2009-02-18$50.86$50.863,469,900
2009-02-17$51.11$51.112,714,700
2009-02-13$52.42$52.421,590,900
2009-02-12$52.61$52.612,460,100
2009-02-11$51.04$51.041,995,300
2009-02-10$50.87$50.872,968,000
2009-02-09$52.16$52.163,742,000
2009-02-06$52.48$52.487,642,400
2009-02-05$53.28$53.284,946,100
2009-02-04$52.75$52.755,722,200
2009-02-03$52.46$52.464,443,100
2009-02-02$50.11$50.113,096,600
2009-01-30$48.65$48.653,397,700
2009-01-29$49.28$49.282,947,300
2009-01-28$49.81$49.814,144,200
2009-01-27$49.27$49.274,394,900
2009-01-26$48.51$48.514,489,700
2009-01-23$47.42$47.427,972,800
2009-01-22$50.88$50.882,959,100
2009-01-21$52.17$52.175,185,000
2009-01-20$49.55$49.554,827,500
2009-01-16$51.05$51.055,976,800
2009-01-15$49.29$49.293,454,000
2009-01-14$48.09$48.093,234,300
2009-01-13$49.63$49.634,576,000
2009-01-12$48.45$48.452,953,300
2009-01-09$48.25$48.253,767,700
2009-01-08$47.95$47.953,235,800
2009-01-07$46.81$46.813,381,300
2009-01-06$46.47$46.473,442,100
2009-01-05$47.44$47.444,439,100
2009-01-02$48.49$48.492,372,900