EXHIBIT 11 BANK OF BOSTON CORPORATION Computation of Earnings Per Common Share (in thousands, except per share amounts) Quarters Ended Nine Months Ended September 30 September 30 EARNINGS 1994 1993 1994 1993 -------- --------- --------- --------- --------- 1. Net income $ 123,969 $ 41,444 $ 314,609 $ 196,514 2. Less: Preferred dividends 9,389 9,383 28,063 25,346 --------- --------- --------- --------- 3. Net income applicable to primary earnings per common share 114,580 32,061 286,546 171,168 4. Add: Interest expense on convertible debentures, net of tax 1,085 1,098 3,219 3,268 --------- --------- --------- --------- 5. Net income applicable to fully diluted earnings per common share $ 115,665 $ 33,159 $ 289,765 $ 174,436 ========= ========= ========= ========= SHARES ------ 6. Weighted average number of common shares outstanding 106,981 105,443 106,602 105,232 7. Incremental shares from assumed exercise of dilutive stock options as of the beginning of the period using the treasury stock method 679 972 759 1,028 8. Incremental shares from assumed conversion of debentures at date of issuance 4,030 4,031 4,030 4,036 --------- --------- --------- --------- 9. Adjusted number of common shares 111,690 110,446 111,391 110,296 ========= ========= ========= ========= PER SHARE CALCULATION --------------------- 10. Primary net income per common share $ 1.07 $ .30 $ 2.69 $ 1.63 (Item 3 /Item 6); see note below 11. Fully diluted net income per common share $ 1.04 $ .30 $ 2.60 $ 1.58 (Item 5 /Item 9); see note below Note - Income per common share before extraordinary items and cumulative effect of accounting changes, net, on both a primary and fully diluted basis for the nine months ended September 30, 1994 and September 30, 1993 are computed by adding to the numerator $6,535 and subtracting from the numerator $24,203, respectively.