Exhibit 12 Statement of computation of ratios. 155 Statements re: Computation of Ratios Item 1(l) Business - Statistical Disclosure VI. Return on Equity and Assets Brenton Banks, Inc. (Dollars in thousands) December 31, 1993 1992 1991 1990 Return on average total assets: Net income (before deduction of minority interest) $ 14,918 13,585 12,198 10,872 * divided by * Average assets $ 1,436,425 1,387,273 1,308,439 1,145,785 Ratio 1.04% 0.98% 0.93% 0.95% Return on average common stockholders' equity: Net income $ 14,250 12,953 11,659 10,339 * divided by * Average common stockholders' equity $ 103,140 91,691 81,731 71,824 Ratio 13.82% 14.13% 14.27% 14.39% Common dividend payout ratio: Cash dividends per share $ 0.600 0.525 0.485 0.410 * divided by * Net income per share $ 2.70 2.50 2.25 2.00 Ratio 22.22% 21.00% 21.56% 20.50% Average equity to average assets: Average equity $ 103,140 91,691 81,731 71,824 * divided by * Average assets $ 1,436,425 1,387,273 1,308,439 1,145,785 Ratio 7.18% 6.61% 6.25% 6.27% Equity to assets ratio: Common stockholders' equity $ 112,418 97,430 86,712 77,258 * divided by * Total assets $ 1,480,596 1,431,140 1,360,942 1,274,301 Ratio 7.59% 6.81% 6.37% 6.06% 156 December 31, 1993 1992 1991 1990 Tier 1 leverage capital ratio: Common stockholders' equity $ 112,418 97,430 86,712 77,258 Minority interest 4,407 3,987 3,716 3,481 Less: intangibles (5,499) (5,834) (6,314) (6,420) Tier 1 capital $ 111,326 95,583 84,114 74,319 * divided by * Total assets $ 1,480,596 1,431,140 1,360,942 1,274,301 Less: intangibles (5,499) (5,834) (6,314) (6,420) Tier 1 assets $ 1,475,097 1,425,306 1,354,628 1,267,881 Ratio 7.55% 6.71% 6.21% 5.86% Primary capital to assets: Common equity $ 112,418 97,430 86,712 77,258 Minority interest 4,407 3,987 3,716 3,481 Allowance for loan losses 9,818 9,006 8,548 8,871 Primary capital $ 126,643 110,423 98,976 89,610 * divided by * Total assets $ 1,480,596 1,431,140 1,360,942 1,274,301 Allowance for loan losses 9,818 9,006 8,548 8,871 Allowable assets $ 1,490,414 1,440,146 1,369,490 1,283,172 Ratio 8.50% 7.67% 7.23% 6.98% 157