Exhibit 12(b) Aon Corporation and Consolidated Subsidiaries Combined With Unconsolidated Subsidiaries Computation of Ratio of Earnings to Combined Fixed Charges and Preferred Stock Dividends First Quarter Ended March 31, Years Ended December 31, --------------- ------------------------------------------- (millions except ratios) 1995 1994 1994 1993 1992(1) 1991 1990 ------ ------ ------ ------ ------- ------- ------ Income from continuing operations before provision for income taxes $168.5 $148.0 $537.6 $479.1 $290.5 $331.5 $325.2 Add back fixed charges: Interest on indebtedness 13.0 11.1 46.4 42.3 41.9 40.7 44.4 Interest on ESOP 1.4 1.5 5.9 6.5 6.9 7.2 7.4 Portion of rents representative of interest factor 7.2 7.9 28.7 26.1 19.2 15.4 13.2 ------ ------ ------ ------ ------ ------ ------ Income as adjusted $190.1 $168.5 $618.6 $554.0 $358.5 $394.8 $390.2 ====== ====== ====== ====== ====== ====== ====== Fixed charges and preferred stock dividends: Interest on indebtedness: Aon Corporation and consolidated subsidiaries $ 13.0 $ 11.1 $ 46.4 $ 42.3 $ 41.9 $ 40.7 $ 43.9 Unconsolidated subsidiaries - - - - - - 0.5 Preferred stock dividends 10.3 12.4 48.4 47.5 20.3 3.5 2.0 ------ ------ ------ ------ ------- ------- ----- Interest and dividends 23.3 23.5 94.8 89.8 62.2 44.2 46.4 Interest on ESOP 1.4 1.5 5.9 6.5 6.9 7.2 7.4 Portion of rents representative of interest factor 7.2 7.9 28.7 26.1 19.2 15.4 13.2 ------ ------ ------ ------ ------- ------- ----- Total fixed charges and preferred stock dividends $ 31.9 $ 32.9 $129.4 $122.4 $ 88.3 $ 66.8 $ 67.0 ======= ====== ====== ====== ====== ====== ====== Ratio of earnings to combined fixed charges and preferred stock dividends 6.0 5.1 4.8 4.5 4.1 5.9 5.8 ======= ====== ====== ====== ====== ====== ====== (1) Income from continuing operations before provision for income taxes excludes the cumulative effect of changes in accounting principles. 2