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Exhibit 99.1

AON CORPORATION
SEGMENT RECLASSIFICATION

			2002
(millions)			1st Qtr.			2nd Qtr.			3rd Qtr.			4th Qtr.			Full Year
REVENUE
	Risk & Insurance Brokerage Services—as reported		$	1,232		$	1,292		$	1,323		$	1,416		$	5,263
		Less: Administrative and marketing services		(71	)		(73	)		(72	)		(59	)		(275	)
		Less: Auto Finance		(4	)		(4	)		(4	)		(3	)		(15	)
		As Reclassified		1,157			1,215			1,247			1,354			4,973
	Consulting			233			248			269			304			1,054
	Insurance Underwriting—as reported			578			677			646			625			2,526
		Plus: Administrative and marketing services		71			73			72			59			275
		As Reclassified		649			750			718			684			2,801
	Corporate & Other—as reported			45			(95	)		8			21			(21	)
		Plus: Auto Finance		4			4			4			3			15
		As Reclassified		49			(91	)		12			24			(6	)
		Total Revenue	$	2,088		$	2,122		$	2,246		$	2,366		$	8,822
INCOME (LOSS) BEFORE INCOME TAXES
	Risk & Insurance Brokerage Services-as reported		$	187		$	142		$	201		$	233		$	763
		Less: Administrative and marketing services		(4	)		(4	)		—			5			(3	)
		Less: Auto Finance		6			6			8			11			31
		As Reclassified		189			144			209			249			791
	Consulting			27			23			26			44			120
	Insurance Underwriting—as reported			64			(2	)		41			49			152
		Plus: Administrative and marketing services		4			4			—			(5	)		3
		As Reclassified		68			2			41			44			155
	Corporate & Other—as reported			(7	)		(147	)		(51	)		(37	)		(242	)
		Plus: Auto Finance		(6	)		(6	)		(8	)		(11	)		(31	)
		As Reclassified		(13	)		(153	)		(59	)		(48	)		(273	)
	Total Income Before Income Taxes		$	271		$	16		$	217		$	289		$	793

AON CORPORATION
SEGMENT RECLASSIFICATION

			2001
(millions)			1st Qtr.			2nd Qtr.			3rd Qtr.			4th Qtr.			Full Year
REVENUE
	Risk & Insurance Brokerage Services—as reported		$	1,117		$	1,154		$	1,112		$	1,276		$	4,659
		Less: Administrative and marketing services		(61	)		(61	)		(76	)		(73	)		(271	)
		Less: Auto Finance		(4	)		(10	)		(6	)		(5	)		(25	)
		As Reclassified		1,052			1,083			1,030			1,198			4,363
	Consulting			212			229			232			265			938
	Insurance Underwriting—as reported			567			548			565			570			2,250
		Plus: Administrative and marketing services		61			61			76			73			271
		As Reclassified		628			609			641			643			2,521
	Corporate & Other—as reported			(85	)		(14	)		3			(75	)		(171	)
		Plus: Auto Finance		4			10			6			5			25
		As Reclassified		(81	)		(4	)		9			(70	)		(146	)
	Total Revenue		$	1,811		$	1,917		$	1,912		$	2,036		$	7,676
INCOME (LOSS) BEFORE INCOME TAXES
	Risk & Insurance Brokerage Services—as reported		$	126		$	78		$	145		$	175		$	524
		Less: Administrative and marketing services		(1	)		(4	)		(10	)		(3	)		(18	)
		Less: Auto Finance		41			5			7			6			59
		As Reclassified		166			79			142			178			565
	Consulting			24			24			29			49			126
	Insurance Underwriting—as reported			67			56			35			(8	)		150
		Plus: Administrative and marketing services		1			4			10			3			18
		As Reclassified		68			60			45			(5	)		168
	Corporate & Other—as reported			(169	)		(94	)		(76	)		(152	)		(491	)
		Plus: Auto Finance		(41	)		(5	)		(7	)		(6	)		(59	)
		As Reclassified		(210	)		(99	)		(83	)		(158	)		(550	)
		Total Income Before Income Taxes	$	48		$	64		$	133		$	64		$	309

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Exhibit 99.1

AON CORPORATION SEGMENT RECLASSIFICATION
AON CORPORATION SEGMENT RECLASSIFICATION