Exhibit 11 TRIMAS CORPORATION AND SUBSIDIARIES COMPUTATION OF EARNINGS PER COMMON SHARE (In Thousands, Except Per Share Amounts) Nine Months Ended Three Months Ended September 30, September 30, 1997 1996 1997 1996 Primary: Net income $55,150 $46,390 $17,430 $14,440 Weighted average common shares outstanding 40,009 36,644 41,329 36,644 Dilution of stock options 334 327 350 333 Weighted average common and common equivalent shares outstanding after assumed exercise of options 40,343 36,971 41,679 36,977 Primary earnings per common share $1.37 $1.25 $.42 $.39 Fully diluted: Net income $55,150 $43,390 $17,430 $14,440 Add after tax convertible debenture related expenses 300 2,760 - 920 Net income as adjusted $55,450 $49,150 $17,430 $15,360 Weighted average common shares outstanding 40,009 36,644 41,329 36,644 Dilution of stock options 357 345 357 345 Addition from assumed conversion of convertible debentures 1,320 5,083 - 5,083 Weighted average common and common equivalent shares outstanding on a fully diluted basis 41,686 42,072 41,686 42,072 Fully diluted earnings per common share $1.33 $1.17 $.42 $.37