EXHIBIT 11 BANK OF BOSTON CORPORATION Computation of Earnings Per Common Share Quarters Ended Nine Months Ended Sept. 30 Sept. 30 EARNINGS (in millions) 1996 1995 1996 1995 -------- ------ ------ ------ ------ 1. Net income $ 80 $ 175 $ 449 $ 498 2. Less: Preferred dividends 9 9 28 28 ------- ------- ------- ------- 3. Net income applicable to primary and fully diluted earnings per common share $ 71 $ 166 421 $ 470 ======= ======= ======= ======= SHARES (in thousands) ------ 4. Weighted average number of common shares outstanding 153,103 155,660 153,715 153,086 5. Incremental shares from assumed exercise of dilutive stock options as of the beginning of the period using the treasury stock method 2,080 1,939 2,585 2,140 6. Incremental shares from assumed conversion 1,181 of debentures at date of issuance -------- ------- ------- ------- 7. Adjusted number of common shares 155,183 157,599 156,300 156,407 ======== ======= ======= ======= PER SHARE CALCULATION --------------------- 8. Primary net income per common share $ .46 $ 1.06 $ 2.74 $ 3.07 (Item 3 divided by Item 4) 9. Fully diluted net income per common share $ .45 $ 1.05 $ 2.69 $ 3.00 (Item 3 divided by Item 7)