EXHIBIT 11 BIOGEN, INC. and SUBSIDIARIES Computation of Earnings Per Share (unaudited) (in thousands, except per share amounts) Three Months Six Months Ended June 30, Ended June 30, 1996 1995 1996 1995 Primary earnings per share Weighted average number of shares outstanding. . . . . . . . . 35,708 33,302 35,654 33,234 Shares deemed outstanding from the assumed exercise of stock options and warrants. . . . . . . . -- 2,435 -- 2,373 ------- ------- ------- ------- Total . . . . . . . . . . . . . . . 35,708 35,737 35,654 35,607 ======= ======= ======= ======= Net income (loss) . . . . . . . . . . $(9,093) $ 714 $(12,751) $ 3,548 ======= ======= ======= ======= Primary earnings (loss) per share of common stock . . . . . . . $ (0.25) $ 0.02 $ (0.36) $ 0.10 ======= ======= ======= ======= Fully diluted earnings per share (a) Weighted average number of shares outstanding. . . . . . . . . 35,708 33,302 35,654 33,234 Shares deemed outstanding from the assumed exercise of stock options and warrants. . . . . . . . -- 2,827 -- 2,827 ------- ------- ------- ------- Total . . . . . . . . . . . . . . . . 35,708 36,129 35,654 36,061 ======= ======= ======= ======= Net income (loss) . . . . . . . . . . $(9,093) $ 714 $(12,751) $ 3,548 ======= ======= ======= ======= Fully diluted earnings (loss) per share of common stock . . . . . $ (0.25) $ 0.02 $ (0.36) $ 0.10 ======= ======= ======= ======= (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%.