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Exhibit 12.1

Aon Corporation and Consolidated Subsidiaries
Combined With Unconsolidated Subsidiaries
Computation of Ratio of Earnings to Fixed Charges

|  | Years Ended December 31, |
--- | --- | --- | ---
(millions except ratio) |  | 2011 |  | 2010 |  | 2009 |  | 2008 |  | 2007 |
Income from continuing operations before income taxes and noncontrolling interests |  | $ | 1,384 |  | $ | 1,059 |  | $ | 949 |  | $ | 879 |  | $ | 1,023 |
Less: Equity in earnings on less than 50% owned entities |  |  | 7 |  |  | 10 |  |  | 11 |  |  | 5 |  |  | 6 |
Add back fixed charges: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest on indebtedness |  |  | 245 |  |  | 182 |  |  | 122 |  |  | 126 |  |  | 138 |
Interest on uncertain tax positions |  |  | — |  |  | (1 | ) |  | 2 |  |  | — |  |  | 2 |
Portion of rents representative of interest factor |  |  | 55 |  |  | 48 |  |  | 48 |  |  | 47 |  |  | 75 |
Income as adjusted |  | $ | 1,677 |  | $ | 1,278 |  | $ | 1,110 |  | $ | 1,047 |  | $ | 1,232 |
Fixed charges: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest on indebtedness |  | $ | 245 |  | $ | 182 |  | $ | 122 |  | $ | 126 |  | $ | 138 |
Interest on uncertain tax positions |  |  | — |  |  | (1 | ) |  | 2 |  |  | — |  |  | 2 |
Portion of rents representative of interest factor |  |  | 55 |  |  | 48 |  |  | 48 |  |  | 47 |  |  | 75 |
Total fixed charges |  | $ | 300 |  | $ | 229 |  | $ | 172 |  | $ | 173 |  | $ | 215 |
Ratio of earnings to fixed charges |  |  | 5.6 |  |  | 5.6 |  |  | 6.5 |  |  | 6.1 |  |  | 5.7 |

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Exhibit 12.1

Aon Corporation and Consolidated Subsidiaries Combined With Unconsolidated Subsidiaries Computation of Ratio of Earnings to Fixed Charges