Exhibit 11 MAHASKA INVESTMENT COMPANY AND SUBSIDIARIES STATEMENT RE: COMPUTATION OF PER SHARE EARNINGS THREE MONTHS ENDED MARCH 31, --------------------- 1998 1997 ---------- ---------- EARNINGS PER SHARE INFORMATION: - --------------------------------------------------- Weighted average number of shares outstanding during the year...................... 3,673,186 3,714,063 Weighted average number of shares outstanding during the year including all dilutive potential shares.......... 3,883,623 3,824,440 Net earnings....................................... $1,429,547 1,378,232 Earnings per share - basic......................... $ 0.39 0.37 Earnings per share - diluted....................... $ 0.37 0.36