Exhibit 12.1

Aon Corporation and Consolidated Subsidiaries

Combined With Unconsolidated Subsidiaries

Computation of Ratio of Earnings to Fixed Charges

		Nine Months ended
		September 30,						Years Ended December 31,
(millions except ratio)		2011			2010			2010			2009			2008			2007			2006
Income from continuing operations before income taxes and noncontrolling interests		$	1,000		$	699		$	1,059		$	949		$	879		$	1,023		$	738
Less: Equity in earnings on less than 50% owned entities		(7		)	3			10			11			5			6			5
Add back fixed charges:
Interest on indebtedness		186			117			182			122			126			138			129
Interest on uncertain tax positions		1			1			(1		)	2			—			2			—
Portion of rents representative of interest factor		37			29			48			48			47			75			79
Income as adjusted		$	1,231		$	843		$	1,278		$	1,110		$	1,047		$	1,232		$	941
Fixed charges:
Interest on indebtedness		$	186		$	117		$	182		$	122		$	126		$	138		$	129
Interest on uncertain tax positions		1			1			(1		)	2			—			2			—
Portion of rents representative of interest factor		37			29			48			48			47			75			79
Total fixed charges		$	224		$	147		$	229		$	172		$	173		$	215		$	208
Ratio of earnings to fixed charges		5.5			5.7			5.6			6.5			6.1			5.7			4.5