Exhibit 11 Morgan Stanley Dean Witter & Co. Computation of Earnings Per Share (In millions, except share data)(1) Three Months Ended Nine Months Ended ------------------------------------ ------------------------------------- August 31 August 31 August 31 August 31 2000 1999 2000 1999 ---------------- ---------------- ---------------- ----------------- Basic: Weighted-average shares outstanding 1,088,218,669 1,100,113,462 1,090,967,941 1,106,725,932 ================ ================ ================ ================= Earnings: Net Income $1,246 $970 $4,248 $3,158 Less: Preferred stock dividend requirements (9) (11) (27) (33) ---------------- ---------------- ---------------- ----------------- Earnings applicable to common shares $1,237 $959 $4,221 $3,125 ================ ================ ================ ================= Basic earnings per share $1.14 $0.87 $3.87 $2.82 ================ ================ ================ ================= Diluted: Weighted-average shares outstanding 1,088,218,669 1,100,113,462 1,090,967,941 1,106,725,932 Average common shares issuable under employee benefit plans 49,085,357 38,008,404 47,705,314 39,275,364 Average common shares issuable upon conversion of ESOP preferred stock(2) - 23,279,780 2,599,147 23,433,516 ---------------- ---------------- ---------------- ----------------- Total weighted-average diluted shares 1,137,304,026 1,161,401,646 1,141,272,402 1,169,434,812 ================ ================ ================ ================= Earnings: Net Income $1,246 $970 $4,248 $3,158 Less: Preferred stock dividend requirements (9) (9) (27) (27) ---------------- ---------------- ---------------- ----------------- Earnings applicable to common shares $1,237 $961 $4,221 $3,131 ================ ================ ================ ================= Diluted earnings per share $1.09 $0.83 $3.70 $2.68 ================ ================ ================ ================= (1) All Share and per share amounts have been retroactively adjusted to reflect a 2:1 stock split, effective on January 26, 2000. (2) ESOP shares were converted to common shares on January 3, 2000.