EXHIBIT 11 BIOGEN, INC. and SUBSIDIARIES Computation of Earnings Per Share (unaudited) (in thousands, except per share amounts) Three Months Nine Months Ended Sep. 30, Ended Sep 30, 1995 1994 1995 1994 Primary earnings per share Weighted average number of shares outstanding . . . . . . . 33,950 33,021 33,473 32,660 Shares deemed outstanding from the assumed exercise of stock options and warrants . . . . . . 2,770 -- 2,505 -- ------- -------- -------- -------- Total . . . . . . . . . . . . . . 36,720 33,021 35,978 32,660 ======= ======== ======== ======== Net income (loss) . . . . . . . . $ 1,128 $(26,421) $ 4,676 $(14,581) ======= ======== ======== ======== Primary earnings (loss) per share of common stock. . . . . . $ 0.03 $ (0.80) $ 0.13 $ (0.45) ======= ======== ======== ======== Fully diluted earnings per share (a) Weighted average number of shares outstanding . . . . . . . 33,950 33,021 33,473 32,660 Shares deemed outstanding from the assumed exercise of stock options and warrants . . . . . . 3,360 -- 3,360 -- ------- -------- -------- -------- Total . . . . . . . . . . . . . . 37,310 33,021 36,833 32,660 ======= ======== ======== ======== Net income (loss) . . . . . . . . $ 1,128 $(26,421) $ 4,676 $(14,581) ======= ======== ======== ======== Fully diluted earnings (loss) per share of common stock. . . . $ 0.03 $ (0.80) $ 0.13 $ (0.45) ======= ======== ======== ======== (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%.