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 — 2008

DateSplit-adjusted closeCumulative dividend-reinvested closeReported volumeOpen priceExchange Volume
2008-12-31$47.63$47.632,117,000
2008-12-30$47.68$47.681,632,600
2008-12-29$46.54$46.541,526,100
2008-12-26$47.31$47.31591,000
2008-12-24$47.20$47.20544,600
2008-12-23$47.05$47.051,668,900
2008-12-22$47.26$47.262,888,700
2008-12-19$46.75$46.756,310,900
2008-12-18$48.01$48.013,434,300
2008-12-17$47.65$47.653,378,100
2008-12-16$49.12$49.124,789,300
2008-12-15$46.18$46.183,876,100
2008-12-12$47.00$47.005,959,100
2008-12-11$47.15$47.152,841,700
2008-12-10$48.05$48.052,993,500
2008-12-09$46.60$46.604,957,300
2008-12-08$48.17$48.176,625,300
2008-12-05$44.25$44.253,706,700
2008-12-04$41.70$41.703,181,900
2008-12-03$42.12$42.124,187,000
2008-12-02$41.43$41.433,528,300
2008-12-01$39.02$39.023,576,400
2008-11-28$42.31$42.311,307,100
2008-11-26$42.00$42.003,099,800
2008-11-25$40.72$40.723,595,400
2008-11-24$40.64$40.643,829,800
2008-11-21$39.64$39.646,564,800
2008-11-20$39.77$39.774,586,300
2008-11-19$41.06$41.063,951,300
2008-11-18$43.80$43.804,061,500
2008-11-17$43.13$43.133,158,400
2008-11-14$43.52$43.523,454,400
2008-11-13$46.70$46.703,740,900
2008-11-12$44.26$44.262,867,900
2008-11-11$46.80$46.803,081,100
2008-11-10$46.72$46.721,812,000
2008-11-07$46.35$46.352,600,500
2008-11-06$44.60$44.603,039,700
2008-11-05$44.84$44.845,329,600
2008-11-04$47.16$47.164,344,300
2008-11-03$46.31$46.315,348,600
2008-10-31$42.55$42.555,464,600
2008-10-30$40.30$40.309,427,000
2008-10-29$41.94$41.945,922,100
2008-10-28$42.35$42.356,278,100
2008-10-27$40.25$40.253,885,500
2008-10-24$41.42$41.423,954,900
2008-10-23$41.39$41.394,845,800
2008-10-22$40.72$40.725,734,200
2008-10-21$43.99$43.994,794,200
2008-10-20$47.49$47.494,130,300
2008-10-17$45.45$45.455,008,400
2008-10-16$43.98$43.986,283,700
2008-10-15$42.46$42.464,349,800
2008-10-14$45.19$45.194,445,200
2008-10-13$47.13$47.135,542,200
2008-10-10$42.78$42.788,277,800
2008-10-09$44.76$44.765,216,400
2008-10-08$46.31$46.315,444,600
2008-10-07$46.50$46.505,955,000
2008-10-06$49.39$49.396,986,500
2008-10-03$50.50$50.504,086,600
2008-10-02$49.68$49.683,636,000
2008-10-01$49.59$49.593,218,600
2008-09-30$50.29$50.295,044,200
2008-09-29$48.89$48.897,654,300
2008-09-26$49.77$49.773,734,000
2008-09-25$48.83$48.833,008,700
2008-09-24$46.72$46.723,181,200
2008-09-23$47.13$47.133,358,600
2008-09-22$48.10$48.103,344,000
2008-09-19$49.98$49.987,303,600
2008-09-18$47.14$47.145,314,400
2008-09-17$45.37$45.375,068,900
2008-09-16$48.48$48.484,234,800
2008-09-15$46.59$46.594,276,800
2008-09-12$48.70$48.703,356,400
2008-09-11$48.47$48.475,972,600
2008-09-10$47.30$47.305,302,900
2008-09-09$46.72$46.724,202,300
2008-09-08$47.50$47.504,589,300
2008-09-05$48.59$48.594,003,800
2008-09-04$48.16$48.165,622,500
2008-09-03$50.17$50.172,897,900
2008-09-02$50.34$50.343,261,700
2008-08-29$50.93$50.932,924,300
2008-08-28$51.33$51.332,983,100
2008-08-27$51.09$51.095,472,400
2008-08-26$52.09$52.094,753,400
2008-08-25$53.48$53.485,144,900
2008-08-22$52.38$52.383,216,100
2008-08-21$53.16$53.162,248,300
2008-08-20$54.10$54.102,418,600
2008-08-19$54.30$54.302,926,400
2008-08-18$54.43$54.433,054,100
2008-08-15$54.65$54.653,912,600
2008-08-14$53.73$53.733,626,800
2008-08-13$52.47$52.473,974,100
2008-08-12$52.21$52.215,337,700
2008-08-11$50.76$50.763,797,500
2008-08-08$49.90$49.903,633,000
2008-08-07$49.88$49.885,472,600
2008-08-06$50.22$50.227,269,500
2008-08-05$50.51$50.517,365,300
2008-08-04$49.74$49.748,889,200
2008-08-01$50.01$50.0136,988,100
2008-07-31$69.76$69.768,795,600
2008-07-30$71.27$71.272,794,600
2008-07-29$70.50$70.503,797,400
2008-07-28$69.49$69.493,143,700
2008-07-25$69.50$69.503,511,000
2008-07-24$71.28$71.284,153,600
2008-07-23$71.38$71.385,535,300
2008-07-22$71.28$71.288,678,700
2008-07-21$66.85$66.855,540,800
2008-07-18$64.65$64.654,266,400
2008-07-17$63.00$63.003,452,800
2008-07-16$63.58$63.584,204,100
2008-07-15$63.48$63.485,493,500
2008-07-14$61.02$61.023,167,600
2008-07-11$62.20$62.203,183,700
2008-07-10$60.94$60.944,149,000
2008-07-09$61.03$61.033,433,500
2008-07-08$62.94$62.945,797,300
2008-07-07$58.87$58.873,123,000
2008-07-03$58.20$58.203,255,200
2008-07-02$58.36$58.363,123,600
2008-07-01$59.34$59.345,228,900
2008-06-30$55.89$55.893,224,500
2008-06-27$57.04$57.047,078,100
2008-06-26$56.34$56.342,283,800
2008-06-25$58.12$58.122,407,500
2008-06-24$57.84$57.843,380,300
2008-06-23$56.53$56.533,344,300
2008-06-20$58.01$58.013,891,200
2008-06-19$59.17$59.172,766,800
2008-06-18$58.50$58.502,955,000
2008-06-17$58.35$58.352,063,700
2008-06-16$59.58$59.581,934,700
2008-06-13$59.90$59.901,968,100
2008-06-12$58.58$58.582,522,600
2008-06-11$58.90$58.903,088,400
2008-06-10$60.44$60.443,391,800
2008-06-09$61.28$61.283,774,500
2008-06-06$62.42$62.423,038,700
2008-06-05$64.57$64.575,343,600
2008-06-04$62.25$62.252,672,900
2008-06-03$61.71$61.713,229,300
2008-06-02$61.41$61.412,572,000
2008-05-30$62.75$62.752,484,600
2008-05-29$63.73$63.731,781,200
2008-05-28$63.13$63.132,429,900
2008-05-27$62.06$62.063,752,600
2008-05-23$61.02$61.021,727,400
2008-05-22$62.08$62.081,232,100
2008-05-21$61.62$61.622,885,600
2008-05-20$63.06$63.061,404,500
2008-05-19$62.75$62.751,850,400
2008-05-16$63.50$63.502,107,300
2008-05-15$62.90$62.901,508,100
2008-05-14$62.35$62.351,792,200
2008-05-13$62.32$62.321,656,100
2008-05-12$63.05$63.051,816,400
2008-05-09$62.07$62.072,057,500
2008-05-08$62.70$62.701,756,700
2008-05-07$62.02$62.021,561,800
2008-05-06$63.14$63.141,678,000
2008-05-05$63.01$63.011,857,500
2008-05-02$62.31$62.312,833,000
2008-05-01$62.33$62.333,480,400
2008-04-30$60.69$60.692,599,400
2008-04-29$61.33$61.336,941,700
2008-04-28$64.67$64.672,600,500
2008-04-25$65.12$65.122,741,900
2008-04-24$63.67$63.672,754,200
2008-04-23$64.51$64.513,111,400
2008-04-22$64.62$64.623,499,000
2008-04-21$64.90$64.903,002,500
2008-04-18$65.00$65.003,773,300
2008-04-17$65.82$65.822,771,300
2008-04-16$65.89$65.893,168,700
2008-04-15$64.93$64.933,659,900
2008-04-14$63.72$63.722,464,100
2008-04-11$64.22$64.223,932,400
2008-04-10$66.43$66.433,576,300
2008-04-09$64.69$64.692,700,000
2008-04-08$65.12$65.123,932,200
2008-04-07$63.79$63.792,311,700
2008-04-04$64.01$64.012,847,300
2008-04-03$62.94$62.942,360,800
2008-04-02$62.91$62.912,481,100
2008-04-01$64.01$64.012,717,400
2008-03-31$61.69$61.693,051,300
2008-03-28$60.73$60.732,953,400
2008-03-27$62.46$62.462,634,200
2008-03-26$62.99$62.993,765,700
2008-03-25$61.19$61.192,515,900
2008-03-24$61.46$61.463,330,200
2008-03-20$59.00$59.006,481,400
2008-03-19$58.40$58.403,752,100
2008-03-18$59.97$59.973,724,900
2008-03-17$58.70$58.703,643,300
2008-03-14$60.33$60.333,823,500
2008-03-13$60.45$60.453,711,000
2008-03-12$59.38$59.384,349,300
2008-03-11$57.68$57.684,141,100
2008-03-10$54.74$54.743,634,000
2008-03-07$56.20$56.204,162,900
2008-03-06$56.63$56.633,729,900
2008-03-05$59.69$59.692,479,300
2008-03-04$59.14$59.144,004,900
2008-03-03$58.84$58.843,337,800
2008-02-29$58.36$58.363,135,700
2008-02-28$60.58$60.581,822,800
2008-02-27$60.13$60.136,284,200
2008-02-26$61.53$61.531,977,600
2008-02-25$61.30$61.301,990,100
2008-02-22$60.34$60.342,527,700
2008-02-21$60.21$60.212,892,400
2008-02-20$61.24$61.242,345,800
2008-02-19$60.67$60.673,681,800
2008-02-15$62.20$62.202,965,200
2008-02-14$62.87$62.873,887,600
2008-02-13$63.24$63.243,588,800
2008-02-12$60.56$60.562,304,800
2008-02-11$60.94$60.943,163,000
2008-02-08$61.50$61.502,525,800
2008-02-07$61.58$61.583,536,400
2008-02-06$60.52$60.524,836,800
2008-02-05$60.52$60.523,005,900
2008-02-04$63.29$63.292,469,900
2008-02-01$61.76$61.762,271,700
2008-01-31$60.95$60.952,412,000
2008-01-30$60.00$60.002,251,300
2008-01-29$61.05$61.053,234,000
2008-01-28$58.13$58.132,726,900
2008-01-25$58.92$58.925,387,700
2008-01-24$58.13$58.133,086,700
2008-01-23$59.23$59.234,849,000
2008-01-22$56.71$56.715,014,700
2008-01-18$59.91$59.916,622,000
2008-01-17$61.05$61.054,641,700
2008-01-16$59.99$59.993,681,000
2008-01-15$59.31$59.313,675,600
2008-01-14$59.98$59.986,044,800
2008-01-11$59.02$59.022,588,800
2008-01-10$59.18$59.185,041,300
2008-01-09$58.40$58.404,894,800
2008-01-08$55.97$55.974,465,800
2008-01-07$59.22$59.225,843,000
2008-01-04$55.22$55.222,877,000
2008-01-03$56.30$56.302,718,100
2008-01-02$55.87$55.873,427,400