1 Detroit Diesel Corporation Form 10-Q (continued) EXHIBIT 11 Detroit Diesel Corporation Statement of Computation of Earnings Per Share Three Months Ended June 30, Six Months Ended June 30, 1998 1997 1998 1997 ---- ---- ---- ---- Basic net income per share Net income $ 10,400,000 $ 7,400,000 $ 20,100,000 $ 13,800,000 Weighted average number of shares outstanding 24,701,899 24,699,566 24,701,858 24,699,566 ------------- ------------- ------------- ------------- Basic net income per share $ 0.42 $ 0.30 $ 0.81 $ 0.56 ============= ============= ============= ============= Diluted net income per share: Net income $ 10,400,000 $ 7,400,000 $ 20,100,000 $ 13,800,000 Weighted average number of shares outstanding 24,701,899 24,699,566 24,701,858 24,699,566 Dilutive effect of stock options 102,768 (1) 40,687 (2) 82,891 (1) 13,964 (2) ------------- ------------- ------------- ------------- Weighted average number of shares outstanding 24,804,667 24,740,253 24,784,749 24,713,530 ------------- ------------- ------------- ------------- Diluted net income per share $ 0.42 $ 0.30 $ 0.81 $ 0.56 ============= ============= ============= ============= (1) Represents the weighted average dilutive effect of 301,310, 265,250, 103,750, 20,000, 2,500 and 219,250 stock options exercisable at $20.00, $17.00, $23.75, $21.81, $23.94 and $22.69 per share, respectively, calculated using the treasury stock method. (2) Represents the weighted average dilutive effect of 300,250, 267,500, 106,000 and 5,000 stock options exercisable at $20.00, $17.00, $23.75 and $18.00 per share, respectively, calculated using the treasury stock method. 15