Exhibit 11 STATE STREET BOSTON CORPORATION COMPUTATION OF EARNINGS PER SHARE (Dollars in thousands, Three Months Ended except per share data) March 31, --------------------------- 1996 1995 ---------- ---------- Primary Average shares outstanding 81,641,835 82,499,807 Common stock equivalents 619,074 390,605 ---------- ---------- Primary shares outstanding 82,260,909 82,890,412 ========== ========== Net income $ 69,750 $ 54,336 ========== ========== Earnings Per Share-primary $ .85 $ .66 ========== ========== Fully Diluted Average shares outstanding 81,641,835 82,499,807 Common stock equivalents 696,879 406,731 Assumed conversion of 7 3/4% convertible subordinated debentures 557,391 581,391 ---------- ---------- Fully diluted average shares outstanding 82,896,105 83,487,929 ========== ========== Net income $ 69,750 $ 54,336 Elimination of interest on 7 3/4% convertible subordinated debentures less related income tax effect 36 37 ---------- ---------- Fully diluted net income $ 69,786 $ 54,373 ========== ========== Earnings Per Share-fully diluted $ .84 $ .65 ========== ==========