EXHIBIT 11 Page 17 BIOGEN, INC. and SUBSIDIARIES Computation of Earnings Per Share (unaudited) (in thousands, except per share amounts) Three months ended March 31, 1997 1996 Primary earnings per share Weighted average number of shares outstanding. . . . . . . . . . . . . . . $ 73,268 $ 71,200 Shares deemed outstanding from the assumed exercise of stock options and warrants. . . . . . . . . . . . . . 3,575 -- -------- -------- Total . . . . . . . . . . . . . . . . . . . . . . 76,843 71,200 ======== ======== Net income(loss). . . . . . . . . . . . . . . . . $ 17,010 $ (3,658) ======== ======== Primary earnings per share of common stock . . . . . . . . . . . . . $ 0.22 $ (0.05) ======== ======== Fully diluted earnings per share (a) Weighted average number of shares outstanding. . . . . . . . . . . . . . . $ 73,268 $ 71,200 Shares deemed outstanding from the assumed exercise of stock options and warrants. . . . . . . . . . . . . . 3,575 -- -------- -------- Total . . . . . . . . . . . . . . . . . . . . . . 76,843 71,200 ======== ======== Net income(loss). . . . . . . . . . . . . . . . . $ 17,010 $ (3,658) ======== ======== Fully diluted earnings per share of common stock . . . . . . . . . . . $ 0.22 $ (0.05) ======== ======== (a) This calculation is submitted in accordance with Regulation S-K item 601 (b) (11) although not required by Footnote 2 to Paragraph 14 of APB Opinion No. 15 because it results in dilution of less than 3%.