1 EXHIBIT 11-18 DTE ENERGY COMPANY BASIC AND DILUTED EARNINGS PER SHARE OF COMMON STOCK Three Months Ended March 31, 2000 ------------------------------------- (Thousands, except per share amounts) BASIC: Net Income ............................. $116,861 Weighted average number of common shares outstanding (a) ............... 144,508 Earnings per share of Common Stock based on weighted average number of shares outstanding ................ $ 0.81 DILUTED: Net Income ............................. $116,861 Weighted average number of common shares outstanding (a) ............... 144,508 Incremental shares from assumed exercise of options ........................... 27 -------- 144,535 ======== Earnings per share of Common Stock assuming exercise of options ......... $ 0.81 - ---------------------------- (a) Based on a daily average.