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 — 2003

DateSplit-adjusted closeCumulative dividend-reinvested closeReported volumeOpen priceExchange Volume
2003-12-31$36.70$36.701,895,400
2003-12-30$36.89$36.892,688,600
2003-12-29$37.49$37.492,179,300
2003-12-26$37.00$37.00447,900
2003-12-24$37.22$37.221,267,700
2003-12-23$36.95$36.951,941,800
2003-12-22$36.82$36.822,565,700
2003-12-19$37.48$37.483,869,400
2003-12-18$37.33$37.332,596,900
2003-12-17$37.00$37.002,392,100
2003-12-16$36.77$36.772,048,800
2003-12-15$36.64$36.643,180,300
2003-12-12$36.94$36.941,909,500
2003-12-11$36.90$36.903,192,400
2003-12-10$35.97$35.973,784,200
2003-12-09$36.75$36.753,048,200
2003-12-08$37.34$37.344,669,000
2003-12-05$38.27$38.272,879,600
2003-12-04$38.50$38.503,053,000
2003-12-03$38.57$38.574,052,400
2003-12-02$38.80$38.803,392,500
2003-12-01$39.24$39.244,091,300
2003-11-28$38.18$38.181,640,200
2003-11-26$38.10$38.103,491,100
2003-11-25$38.18$38.1815,130,200
2003-11-24$37.53$37.534,507,600
2003-11-21$36.25$36.253,667,300
2003-11-20$35.94$35.944,647,500
2003-11-19$35.19$35.194,617,900
2003-11-18$34.43$34.435,153,100
2003-11-17$35.26$35.265,099,000
2003-11-14$35.75$35.756,092,800
2003-11-13$35.25$35.2510,315,300
2003-11-12$33.42$33.4217,861,500
2003-11-11$33.40$33.404,870,600
2003-11-10$33.07$33.073,250,300
2003-11-07$34.05$34.052,042,800
2003-11-06$34.48$34.483,201,200
2003-11-05$34.01$34.015,018,100
2003-11-04$33.26$33.2610,663,300
2003-11-03$35.20$35.202,409,400
2003-10-31$35.14$35.142,461,500
2003-10-30$34.73$34.732,493,500
2003-10-29$34.85$34.855,691,400
2003-10-28$34.27$34.274,407,700
2003-10-27$32.42$32.422,310,300
2003-10-24$32.73$32.731,489,800
2003-10-23$32.45$32.453,789,500
2003-10-22$32.24$32.243,485,700
2003-10-21$33.43$33.432,902,300
2003-10-20$32.60$32.603,449,800
2003-10-17$32.60$32.602,860,300
2003-10-16$33.74$33.741,728,800
2003-10-15$33.65$33.651,994,600
2003-10-14$34.13$34.133,582,900
2003-10-13$34.03$34.034,644,000
2003-10-10$33.17$33.173,994,300
2003-10-09$33.31$33.317,116,200
2003-10-08$33.87$33.873,650,300
2003-10-07$34.45$34.454,036,800
2003-10-06$33.94$33.943,019,300
2003-10-03$34.78$34.783,333,000
2003-10-02$34.36$34.363,675,100
2003-10-01$33.68$33.683,599,400
2003-09-30$33.29$33.295,415,800
2003-09-29$33.88$33.886,493,200
2003-09-26$34.25$34.252,421,800
2003-09-25$34.84$34.842,879,400
2003-09-24$35.33$35.333,936,700
2003-09-23$37.00$37.001,875,400
2003-09-22$36.77$36.772,858,300
2003-09-19$37.77$37.772,956,100
2003-09-18$37.50$37.503,932,300
2003-09-17$36.79$36.793,644,000
2003-09-16$35.54$35.542,613,500
2003-09-15$35.55$35.553,185,400
2003-09-12$35.99$35.992,746,700
2003-09-11$35.68$35.684,262,400
2003-09-10$34.59$34.592,415,200
2003-09-09$35.78$35.783,681,900
2003-09-08$35.90$35.906,197,900
2003-09-05$34.41$34.412,764,000
2003-09-04$34.53$34.532,775,900
2003-09-03$34.16$34.162,311,500
2003-09-02$34.88$34.883,159,600
2003-08-29$34.72$34.723,475,400
2003-08-28$33.71$33.711,806,200
2003-08-27$33.41$33.411,392,500
2003-08-26$33.44$33.442,015,700
2003-08-25$33.49$33.491,470,900
2003-08-22$32.84$32.841,753,700
2003-08-21$33.74$33.742,346,500
2003-08-20$33.43$33.431,957,700
2003-08-19$33.22$33.223,482,200
2003-08-18$33.86$33.862,069,100
2003-08-15$33.16$33.161,521,800
2003-08-14$32.70$32.702,576,400
2003-08-13$33.02$33.024,066,500
2003-08-12$33.10$33.102,336,500
2003-08-11$32.28$32.281,489,100
2003-08-08$32.22$32.221,751,900
2003-08-07$32.46$32.462,379,300
2003-08-06$31.89$31.893,438,300
2003-08-05$32.51$32.512,686,800
2003-08-04$33.46$33.463,278,400
2003-08-01$33.25$33.252,620,200
2003-07-31$33.76$33.762,211,100
2003-07-30$33.27$33.272,662,000
2003-07-29$33.29$33.295,608,900
2003-07-28$33.87$33.873,599,900
2003-07-25$34.59$34.593,315,500
2003-07-24$34.11$34.1110,183,700
2003-07-23$36.05$36.052,926,200
2003-07-22$35.50$35.502,914,400
2003-07-21$35.47$35.474,367,000
2003-07-18$35.00$35.007,982,700
2003-07-17$35.80$35.804,837,600
2003-07-16$36.35$36.353,190,800
2003-07-15$36.55$36.555,006,300
2003-07-14$36.71$36.716,231,100
2003-07-11$37.82$37.823,321,300
2003-07-10$37.29$37.298,820,600
2003-07-09$38.55$38.556,373,500
2003-07-08$37.96$37.964,810,300
2003-07-07$36.90$36.904,417,300
2003-07-03$35.83$35.833,730,700
2003-07-02$35.98$35.985,736,700
2003-07-01$35.32$35.3210,516,200
2003-06-30$33.96$33.968,169,500
2003-06-27$35.29$35.297,891,200
2003-06-26$36.55$36.557,697,800
2003-06-25$37.02$37.0213,842,600
2003-06-24$36.52$36.5212,410,400
2003-06-23$36.96$36.9625,737,200
2003-06-20$38.97$38.973,392,800
2003-06-19$39.00$39.005,642,200
2003-06-18$40.34$40.343,039,000
2003-06-17$41.57$41.572,456,200
2003-06-16$41.45$41.453,020,000
2003-06-13$40.14$40.142,454,000
2003-06-12$41.22$41.224,514,300
2003-06-11$40.29$40.294,101,000
2003-06-10$39.14$39.142,371,000
2003-06-09$38.36$38.363,779,300
2003-06-06$39.50$39.506,073,900
2003-06-05$40.94$40.948,450,600
2003-06-04$38.56$38.564,552,700
2003-06-03$38.31$38.313,418,700
2003-06-02$38.57$38.575,152,500
2003-05-30$38.22$38.224,482,900
2003-05-29$37.19$37.195,388,300
2003-05-28$38.77$38.773,432,100
2003-05-27$39.65$39.657,195,400
2003-05-23$37.76$37.769,195,700
2003-05-22$35.00$35.003,529,000
2003-05-21$33.30$33.302,504,800
2003-05-20$33.53$33.532,082,900
2003-05-19$34.13$34.135,385,100
2003-05-16$34.18$34.183,111,100
2003-05-15$34.44$34.442,134,000
2003-05-14$33.38$33.382,126,000
2003-05-13$33.46$33.461,394,600
2003-05-12$33.70$33.702,430,500
2003-05-09$33.03$33.032,710,900
2003-05-08$32.35$32.352,803,000
2003-05-07$32.80$32.803,333,600
2003-05-06$32.55$32.555,601,600
2003-05-05$34.15$34.155,460,200
2003-05-02$34.18$34.183,503,800
2003-05-01$33.06$33.062,889,800
2003-04-30$32.75$32.752,769,100
2003-04-29$33.15$33.152,071,600
2003-04-28$33.00$33.002,634,700
2003-04-25$32.22$32.224,009,100
2003-04-24$33.85$33.855,069,900
2003-04-23$33.86$33.863,933,700
2003-04-22$32.95$32.953,129,000
2003-04-21$31.85$31.851,952,800
2003-04-17$31.88$31.884,562,200
2003-04-16$30.07$30.076,050,000
2003-04-15$31.35$31.353,869,700
2003-04-14$31.39$31.392,390,000
2003-04-11$31.63$31.633,625,500
2003-04-10$31.59$31.5911,873,200
2003-04-09$33.94$33.943,788,700
2003-04-08$34.58$34.584,689,300
2003-04-07$34.84$34.847,355,200
2003-04-04$36.95$36.954,403,900
2003-04-03$37.26$37.267,372,300
2003-04-02$35.14$35.143,373,000
2003-04-01$34.10$34.102,524,900
2003-03-31$34.22$34.222,592,500
2003-03-28$35.36$35.362,252,300
2003-03-27$35.54$35.543,461,700
2003-03-26$34.37$34.372,862,500
2003-03-25$34.30$34.303,619,000
2003-03-24$32.88$32.883,114,300
2003-03-21$34.37$34.375,135,800
2003-03-20$34.50$34.505,020,100
2003-03-19$33.83$33.834,759,700
2003-03-18$34.08$34.085,298,400
2003-03-17$32.62$32.625,881,800
2003-03-14$30.34$30.345,621,600
2003-03-13$30.49$30.495,346,500
2003-03-12$28.38$28.383,457,600
2003-03-11$28.09$28.092,568,300
2003-03-10$28.69$28.692,651,100
2003-03-07$28.60$28.604,042,400
2003-03-06$28.72$28.723,147,000
2003-03-05$28.67$28.673,037,800
2003-03-04$28.72$28.721,956,600
2003-03-03$29.10$29.104,056,900
2003-02-28$28.75$28.753,147,600
2003-02-27$29.16$29.162,118,800
2003-02-26$28.57$28.573,008,800
2003-02-25$29.51$29.515,781,500
2003-02-24$29.10$29.101,939,400
2003-02-21$29.99$29.993,214,700
2003-02-20$29.50$29.503,277,300
2003-02-19$30.37$30.371,801,500
2003-02-18$30.65$30.652,266,600
2003-02-14$29.90$29.902,435,700
2003-02-13$29.46$29.464,330,500
2003-02-12$30.27$30.272,347,000
2003-02-11$30.90$30.902,456,200
2003-02-10$30.75$30.751,905,300
2003-02-07$30.86$30.862,667,200
2003-02-06$30.71$30.712,271,900
2003-02-05$30.98$30.984,131,500
2003-02-04$30.71$30.714,739,500
2003-02-03$32.41$32.412,710,500
2003-01-31$32.08$32.083,397,900
2003-01-30$31.57$31.573,360,100
2003-01-29$31.50$31.503,286,400
2003-01-28$32.22$32.223,895,400
2003-01-27$31.89$31.894,301,500
2003-01-24$32.48$32.485,661,700
2003-01-23$34.15$34.155,091,600
2003-01-22$34.58$34.583,986,500
2003-01-21$35.37$35.373,999,500
2003-01-17$35.05$35.054,753,500
2003-01-16$36.05$36.0512,192,900
2003-01-15$33.42$33.424,806,800
2003-01-14$34.05$34.053,198,200
2003-01-13$34.04$34.043,207,700
2003-01-10$33.87$33.873,381,500
2003-01-09$33.15$33.152,917,200
2003-01-08$33.03$33.032,896,400
2003-01-07$34.24$34.243,088,800
2003-01-06$34.23$34.233,248,100
2003-01-03$33.69$33.691,985,400
2003-01-02$34.34$34.343,464,100