8-K

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SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the
Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): July 11, 2003

Aon CORPORATION
(Exact name of Registrant as Specified in Its Charter)

Delaware (State or Other Jurisdiction of Incorporation)	1-7933 (Commission File Number)	36-3051915 (I.R.S. Employer Identification No.)
200 East Randolph Street, Chicago, Illinois (Address of Principal Executive Offices)		60601 (Zip Code)

Registrant's Telephone Number, Including Area Code: (312) 381-1000

Not Applicable
(Former Name or Former Address, if Changed Since Last Report)

Item 9. Regulation FD Disclosure.

        The information required by Item 12. Results of Operation and Financial Condition is being provided under Item 9 pursuant to SEC guidance in SEC Release No. 33-8216.

        The information in this Form 8-K and the Exhibits attached hereto shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, except as shall be expressly set forth by specific references in such filing.

Highlights

        On May 2, 2003, Aon filed a Form 8-K that included enhanced reported revenue information for 2002 and 2001 within the segments. This Form 8-K filing supplements the May 2 Form 8-K by adding reclassified segment information and additional revenue information for each quarter and for the full year ended December 31, 2000 and additional revenue information for first quarter 2003. Organic revenue growth data for the sub-segments and pretax margins for the segments before previously reported special and unusual charges have also been added. Schedules including this information are attached for each quarter and full year ended December 31, 2002 and 2001, and for first quarter 2003.

        On May 5, 2003, a Form 8-K was filed in conjunction with the release of first quarter 2003 financial results that included enhanced sub-segment revenue detail with organic revenue growth information. The percentages originally reported in our May 5 Form 8-K (and first quarter 2003 Form 10Q) for organic revenue growth for the Risk Management and Insurance Brokerage—International and Claims Services sub-segments have changed based upon a review of the underlying calculation. The organic revenue growth percentages were originally reported as 11% and 7%, respectively, and were amended to 10% and 14%, respectively. This change did not impact reported revenue growth information for either the sub-segments or the total Risk and Insurance Brokerage Services segment. When we refer to organic revenue growth, we exclude the impact of foreign exchange. In addition, we also exclude the impact of acquisitions, dispositions, transfers, investment income and other items. Written premium and fees are the basis for organic revenue growth within the Insurance Underwriting segment, whereas reported revenues reflect earned premiums.

        This supplemental information is being furnished to assist investors in analyzing the Company's historical 2002, 2001 and 2000 financial information compared with the enhanced presentation that began in first quarter 2003.

        Exhibit 99.1 from the May 2, 2003 Form 8-K (that provides segment reclassification information for 2002 and 2001) is attached as Exhibit 99.1 with the addition of quarterly and full year 2000 results.

        Exhibit 99.2 from the May 2, 2003 Form 8-K (that provides additional revenue information) is attached as Exhibit 99.2 with the addition of first quarter 2003 and quarterly and full year 2000 results.

        Exhibit 99.3 from the May 2, 2003 Form 8-K (that provides various segment information after the reclassification, including organic revenue growth and reported pretax margins) has been expanded to include sub-segment organic revenue growth detail and is attached as Exhibit 99.3 with the addition of first quarter 2003 results.

        A reconciliation of reported revenue growth to organic revenue growth for the segments and sub-segments is attached as Exhibit 99.4 for first quarter 2003 and for each quarter and full year ended December 31, 2002 and 2001.

        Exhibit 99.4 from the May 2, 2003 Form 8-K (that provides segment information after the reclassification—excluding previously reported special and unusual charges) has been expanded to include pretax margins—excluding previously reported special and unusual charges and is attached as Exhibit 99.5 with the addition of first quarter 2003 results.

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SIGNATURES

        Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

Aon CORPORATION
By:	/s/  DAVID P. BOLGER David P. Bolger Executive Vice President and Chief Financial Officer

Date: July 11, 2003

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EXHIBIT INDEX

        The following is a list of the exhibits filed herewith.

Exhibit Number	Description of Exhibit
99.1	Reclassified Segment Information for: (i) the quarters ended March 31, June 30, September 30 and December 31, 2002; (ii) the quarters ended March 31, June 30, September 30 and December 31, 2001; (iii) the quarters ended March 31, June 30, September 30 and December 31, 2000; and (iv) the years ended December 31, 2002, 2001and 2000.
99.2	Additional Revenue Information for: (i) the quarter ended March 31, 2003; (ii) the quarters ended March 31, June 30, September 30 and December 31, 2002; (iii) the quarters ended March 31, June 30, September 30 and December 31, 2001; (iv) the quarters ended March 31, June 30, September 30 and December 31, 2000; and (v) the years ended December 31, 2002, 2001 and 2000.
99.3	Various Segment Information—After Reclassification for: (i) the quarter ended March 31, 2003; (ii) the quarters ended March 31, June 30, September 30 and December 31, 2002; (iii) the quarters ended March 31, June 30, September 30 and December 31, 2001; and (iv) the years ended December 31, 2002 and 2001.
99.4	Reconciliation of Reported Revenue Growth to Organic Revenue Growth for: (i) the quarter ended March 31, 2003; (ii) the quarters ended March 31, June 30, September 30 and December 31, 2002; (iii) the quarters ended March 31, June 30, September 30 and December 31, 2001; and (iv) the years ended December 31, 2002 and 2001.
99.5	Segments as Reclassified—Excluding Previously Reported Special & Unusual Charges for: (i) the quarter ended March 31, 2003; (ii) the quarters ended March 31, June 30, September 30 and December 31, 2002; (iii) the quarters ended March 31, June 30, September 30 and December 31, 2001; and (iv) the years ended December 31, 2002 and 2001.

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Item 9. Regulation FD Disclosure.

SIGNATURES
EXHIBIT INDEX

EX-99.1

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Exhibit 99.1

AON CORPORATION
SEGMENT RECLASSIFICATION

			2002
			1st Qtr.			2nd Qtr.			3rd Qtr.			4th Qtr.			Full Year
			(millions)
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
			1st Qtr.			2nd Qtr.			3rd Qtr.			4th Qtr.			Full Year
			(millions)
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

AON CORPORATION
SEGMENT RECLASSIFICATION

			2000
			1st Qtr.			2nd Qtr.			3rd Qtr.			4th Qtr.			Full Year
			(millions)
REVENUE
	Risk & Insurance Brokerage Services—originally reported		$	1,074		$	1,065		$	1,042		$	1,186		$	4,367
		Less: Administrative and marketing services		(56	)		(57	)		(58	)		(75	)		(246	)
		Less: Auto Finance		(12	)		(10	)		(9	)		(10	)		(41	)
		As Reclassified		1,006			998			975			1,101			4,080
	Consulting			176			180			182			232			770
	Insurance Underwriting—originally reported			530			552			536			549			2,167
		Plus: Administrative and marketing services		56			57			58			75			246
		As Reclassified		586			609			594			624			2,413
	Corporate—originally reported			30			22			25			(6	)		71
		Plus: Auto Finance		12			10			9			10			41
		As Reclassified		42			32			34			4			112
		Total Revenue	$	1,810		$	1,819		$	1,785		$	1,961		$	7,375
INCOME (LOSS) BEFORE INCOME TAXES
	Risk & Insurance Brokerage Services—originally reported		$	180		$	182		$	183		$	145		$	690
		Less: Administrative and marketing services		(1	)		(3	)		(4	)		(17	)		(25	)
		Less: Auto Finance		(2	)		(1	)		—			(1	)		(4	)
		As Reclassified		177			178			179			127			661
	Consulting			19			23			26			38			106
	Insurance Underwriting—originally reported			67			79			81			73			300
		Plus: Administrative and marketing services		1			3			4			17			25
		As Reclassified		68			82			85			90			325
	Corporate—originally reported			(48	)		(56	)		(46	)		(92	)		(242	)
		Plus: Auto Finance		2			1			—			1			4
		As Reclassified		(46	)		(55	)		(46	)		(91	)		(238	)
		Total Income Before Income Taxes	$	218		$	228		$	244		$	164		$	854

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AON CORPORATION SEGMENT RECLASSIFICATION

EX-99.2

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Exhibit 99.2

AON CORPORATION
ADDITIONAL REVENUE INFORMATION

			2002												2003
			1st Qtr.		2nd Qtr.			3rd Qtr.		4th Qtr.		Full Year			1st Qtr.
			(millions)
REVENUE
Risk & Insurance Brokerage Services:
	Risk Management & Insurance Brokerage—Americas		$	448	$	517		$	534	$	607	$	2,106		$	507
	Risk Management & Insurance Brokerage—International			420		413			403		459		1,695			524
	Reinsurance Brokerage & Related Services			199		192			210		189		790			242
	Claims Services			90		93			100		99		382			101
		Total Risk & Insurance Brokerage Services		1,157		1,215			1,247		1,354		4,973			1,374
Consulting:
	Benefits, Compensation, Management & Communications Consulting			183		194			193		226		796			209
	Human Resource Outsourcing			50		54			76		78		258			73
		Total Consulting		233		248			269		304		1,054			282
Insurance Underwriting:
	Accident & Health and Life			389		441			415		394		1,639			399
	Warranty, Credit and Property & Casualty			260		309			303		290		1,162			310
		Total Insurance Underwriting		649		750			718		684		2,801			709
Corporate & Other:
	Auto Finance			4		4			4		3		15			4
	Corporate			45		(95	)		8		21		(21	)		31
		Total Corporate & Other		49		(91	)		12		24		(6	)		35
Intersegment Revenues				—		—			—		—		—			(12	)
		Total Aon Corporation	$	2,088	$	2,122		$	2,246	$	2,366	$	8,822		$	2,388

AON CORPORATION
ADDITIONAL REVENUE INFORMATION

			2001
			1st Qtr.			2nd Qtr.			3rd Qtr.		4th Qtr.			Full Year
			(millions)
REVENUE
Risk & Insurance Brokerage Services:
	Risk Management & Insurance Brokerage—Americas		$	423		$	480		$	441	$	576		$	1,920
	Risk Management & Insurance Brokerage—International			375			342			322		374			1,413
	Reinsurance Brokerage & Related Services			175			171			174		148			668
	Claims Services			79			90			93		100			362
		Total Risk & Insurance Brokerage Services		1,052			1,083			1,030		1,198			4,363
Consulting:
	Benefits, Compensation, Management & Communications Consulting			169			181			180		210			740
	Human Resource Outsourcing			43			48			52		55			198
		Total Consulting		212			229			232		265			938
Insurance Underwriting:
	Accident & Health and Life			348			354			357		370			1,429
	Warranty, Credit and Property & Casualty			280			255			284		273			1,092
		Total Insurance Underwriting		628			609			641		643			2,521
Corporate & Other:
	Auto Finance			4			10			6		5			25
	Corporate			(85	)		(14	)		3		(75	)		(171	)
		Total Corporate & Other		(81	)		(4	)		9		(70	)		(146	)
		Total Aon Corporation	$	1,811		$	1,917		$	1,912	$	2,036		$	7,676

AON CORPORATION
ADDITIONAL REVENUE INFORMATION

			2000
			1st Qtr.		2nd Qtr.		3rd Qtr.		4th Qtr.			Full Year
			(millions)
REVENUE
Risk & Insurance Brokerage Services:
	Risk Management & Insurance Brokerage—Americas		$	420	$	456	$	448	$	544		$	1,868
	Risk Management & Insurance Brokerage—International			370		332		301		332			1,335
	Reinsurance Brokerage & Related Services			156		149		163		157			625
	Claims Services			60		61		63		68			252
		Total Risk & Insurance Brokerage Services		1,006		998		975		1,101			4,080
Consulting:
	Benefits, Compensation, Management & Communications Consulting			143		147		148		198			636
	Human Resource Outsourcing			33		33		34		34			134
		Total Consulting		176		180		182		232			770
Insurance Underwriting:
	Accident & Health and Life			319		323		330		349			1,321
	Warranty, Credit and Property & Casualty			267		286		264		275			1,092
		Total Insurance Underwriting		586		609		594		624			2,413
Corporate & Other:
	Auto Finance			12		10		9		10			41
	Corporate			30		22		25		(6	)		71
		Total Corporate & Other		42		32		34		4			112
		Total Aon Corporation	$	1,810	$	1,819	$	1,785	$	1,961		$	7,375

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AON CORPORATION ADDITIONAL REVENUE INFORMATION

EX-99.3

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Exhibit 99.3

AON CORPORATION
VARIOUS SEGMENT INFORMATION—AFTER RECLASSIFICATION

				2002															2003
				1st Qtr.			2nd Qtr.			3rd Qtr.			4th Qtr.			Full Year			1st Qtr.
				(millions)
REVENUE
	Risk & Insurance Brokerage Services			$	1,157		$	1,215		$	1,247		$	1,354		$	4,973		$	1,374
	Consulting				233			248			269			304			1,054			282
	Insurance Underwriting				649			750			718			684			2,801			709
	Corporate & Other				49			(91	)		12			24			(6	)		35
	Intersegment Revenues				—			—			—			—			—			(12	)
			Total Revenue	$	2,088		$	2,122		$	2,246		$	2,366		$	8,822		$	2,388
INCOME (LOSS) BEFORE INCOME TAXES
	Risk & Insurance Brokerage Services			$	189		$	144		$	209		$	249		$	791		$	230
	Consulting				27			23			26			44			120			20
	Insurance Underwriting				68			2			41			44			155			63
	Corporate & Other				(13	)		(153	)		(59	)		(48	)		(273	)		(57	)
			Total Income Before Income Taxes	$	271		$	16		$	217		$	289		$	793		$	256
INCOME BEFORE INCOME TAXES—MARGINS
	Risk & Insurance Brokerage Services				16.3	%		11.9	%		16.8	%		18.4	%		15.9	%		16.7	%
	Consulting				11.6	%		9.3	%		9.7	%		14.5	%		11.4	%		7.1	%
	Insurance Underwriting				10.5	%		0.3	%		5.7	%		6.4	%		5.5	%		8.9	%
			Total Income Before Income Taxes—Margins		13.0	%		0.8	%		9.7	%		12.2	%		9.0	%		10.7	%
ORGANIC REVENUE GROWTH
	Risk & Insurance Brokerage Services:
		Risk Management & Insurance Brokerage—Americas			9	%		8	%		26	%		11	%		13	%		13	%
		Risk Management & Insurance Brokerage—International			16	%		13	%		14	%		12	%		14	%		10	%
		Reinsurance Brokerage & Related Services			25	%		14	%		34	%		21	%		23	%		15	%
		Claims Services			10	%		2	%		6	%		-2	%		4	%		14	%
			Total Risk & Insurance Brokerage Services		13	%		10	%		21	%		10	%		13	%		12	%
	Consulting:
		Benefits, Compensation, Management and Communications Consulting			6	%		6	%		6	%		5	%		6	%		6	%
		Human Resource Outsourcing			3	%		3	%		44	%		37	%		22	%		38	%
			Total Consulting		4	%		6	%		14	%		12	%		9	%		13	%
	Insurance Underwriting:
		Accident & Health and Life			30	%		20	%		8	%		11	%		16	%		5	%
		Warranty, Credit and Property & Casualty			6	%		26	%		5	%		-5	%		5	%		20	%
			Total Insurance Underwriting		17	%		23	%		7	%		4	%		11	%		12	%
	Total Organic Revenue Growth				14	%		14	%		15	%		9	%		12	%		12	%

AON CORPORATION
VARIOUS SEGMENT INFORMATION—AFTER RECLASSIFICATION

				2001
				1st Qtr.			2nd Qtr.			3rd Qtr.			4th Qtr.			Full Year
				(millions)
REVENUE
	Risk & Insurance Brokerage Services			$	1,052		$	1,083		$	1,030		$	1,198		$	4,363
	Consulting				212			229			232			265			938
	Insurance Underwriting				628			609			641			643			2,521
	Corporate & Other				(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			$	166		$	79		$	142		$	178		$	565
	Consulting				24			24			29			49			126
	Insurance Underwriting				68			60			45			(5	)		168
	Corporate & Other				(210	)		(99	)		(83	)		(158	)		(550	)
			Total Income Before Income Taxes	$	48		$	64		$	133		$	64		$	309
INCOME BEFORE INCOME TAXES—MARGINS
	Risk & Insurance Brokerage Services				15.8	%		7.3	%		13.8	%		14.9	%		12.9	%
	Consulting				11.3	%		10.5	%		12.5	%		18.5	%		13.4	%
	Insurance Underwriting				10.8	%		9.9	%		7.0	%		-0.8	%		6.7	%
			Total Income Before Income Taxes—Margins		2.7	%		3.3	%		7.0	%		3.1	%		4.0	%
ORGANIC REVENUE GROWTH
	Risk & Insurance Brokerage Services:
		Risk Management & Insurance Brokerage—Americas			0	%		6	%		-2	%		0	%		1	%
		Risk Management & Insurance Brokerage—International			8	%		9	%		7	%		10	%		9	%
		Reinsurance Brokerage & Related Services			18	%		23	%		4	%		13	%		14	%
		Claims Services			46	%		51	%		49	%		45	%		47	%
			Total Risk & Insurance Brokerage Services		8	%		12	%		6	%		9	%		9	%
	Consulting:
		Benefits, Compensation, Management and Communications Consulting			11	%		10	%		6	%		8	%		9	%
		Human Resource Outsourcing			-2	%		6	%		-1	%		4	%		2	%
			Total Consulting		8	%		9	%		4	%		7	%		7	%
	Insurance Underwriting:
		Accident & Health and Life			8	%		8	%		10	%		16	%		11	%
		Warranty, Credit and Property & Casualty			1	%		-7	%		6	%		1	%		0	%
			Total Insurance Underwriting		5	%		1	%		8	%		8	%		5	%
	Total Organic Revenue Growth				7	%		8	%		7	%		9	%		8	%

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AON CORPORATION VARIOUS SEGMENT INFORMATION—AFTER RECLASSIFICATION

EX-99.4

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Exhibit 99.4

AON CORPORATION
RECONCILIATION OF REPORTED REVENUE GROWTH TO ORGANIC REVENUE GROWTH

			1st Quarter 2003
			Reported Revenue Growth		Less: Currency Impact		Less: All Other (1)		Organic Revenue Growth
Risk & Insurance Brokerage Services:
	Risk Management & Insurance Brokerage—Americas		13	%	-2	%	2	%	13	%
	Risk Management & Insurance Brokerage—International		25	%	14	%	1	%	10	%
	Reinsurance Brokerage & Related Services		22	%	9	%	-2	%	15	%
	Claims Services		12	%	3	%	-5	%	14	%
		Total Risk & Insurance Brokerage Services	19	%	7	%	0	%	12	%
Consulting:
	Benefits, Compensation, Management and Communications Consulting		14	%	5	%	3	%	6	%
	Human Resource Outsourcing		46	%	3	%	5	%	38	%
		Total Consulting	21	%	6	%	2	%	13	%
Insurance Underwriting:
	Accident & Health and Life		3	%	2	%	-4	%	5	%
	Warranty, Credit and Property & Casualty		19	%	3	%	-4	%	20	%
		Total Insurance Underwriting	9	%	2	%	-5	%	12	%
Total Operating Segments (after eliminations)			14	%	5	%	-3	%	12	%

(1)

Includes items discussed in the organic revenue growth description, beyond currency impact.

AON CORPORATION
RECONCILIATION OF REPORTED REVENUE GROWTH TO ORGANIC REVENUE GROWTH

			1st Quarter 2002
			Reported Revenue Growth		Less: Currency Impact		Less: All Other (1)		Organic Revenue Growth
Risk & Insurance Brokerage Services:
	Risk Management & Insurance Brokerage—Americas		6	%	-1	%	-2	%	9	%
	Risk Management & Insurance Brokerage—International		12	%	-4	%	0	%	16	%
	Reinsurance Brokerage & Related Services		14	%	-2	%	-9	%	25	%
	Claims Services		14	%	-1	%	5	%	10	%
		Total Risk & Insurance Brokerage Services	10	%	-2	%	-1	%	13	%
Consulting:
	Benefits, Compensation, Management and Communications Consulting		8	%	-1	%	3	%	6	%
	Human Resource Outsourcing		16	%	-1	%	14	%	3	%
		Total Consulting	10	%	-1	%	7	%	4	%
Insurance Underwriting:
	Accident & Health and Life		12	%	-4	%	-14	%	30	%
	Warranty, Credit and Property & Casualty		-7	%	0	%	-13	%	6	%
		Total Insurance Underwriting	3	%	-2	%	-12	%	17	%
Total Operating Segments			8	%	-2	%	-4	%	14	%

			2nd Quarter 2002
			Reported Revenue Growth		Less: Currency Impact		Less: All Other (1)		Organic Revenue Growth
Risk & Insurance Brokerage Services:
	Risk Management & Insurance Brokerage—Americas		8	%	-1	%	1	%	8	%
	Risk Management & Insurance Brokerage—International		21	%	3	%	5	%	13	%
	Reinsurance Brokerage & Related Services		12	%	1	%	-3	%	14	%
	Claims Services		3	%	1	%	0	%	2	%
		Total Risk & Insurance Brokerage Services	12	%	1	%	1	%	10	%
Consulting:
	Benefits, Compensation, Management and Communications Consulting		7	%	1	%	0	%	6	%
	Human Resource Outsourcing		13	%	1	%	9	%	3	%
		Total Consulting	8	%	1	%	1	%	6	%
Insurance Underwriting:
	Accident & Health and Life		25	%	0	%	5	%	20	%
	Warranty, Credit and Property & Casualty		21	%	1	%	-6	%	26	%
		Total Insurance Underwriting	23	%	0	%	0	%	23	%
Total Operating Segments			15	%	1	%	0	%	14	%

			3rd Quarter 2002
			Reported Revenue Growth		Less: Currency Impact		Less: All Other (1)		Organic Revenue Growth
Risk & Insurance Brokerage Services:
	Risk Management & Insurance Brokerage—Americas		21	%	-2	%	-3	%	26	%
	Risk Management & Insurance Brokerage—International		25	%	7	%	4	%	14	%
	Reinsurance Brokerage & Related Services		21	%	4	%	-17	%	34	%
	Claims Services		8	%	2	%	0	%	6	%
		Total Risk & Insurance Brokerage Services	21	%	2	%	-2	%	21	%
Consulting:
	Benefits, Compensation, Management and Communications Consulting		7	%	2	%	-1	%	6	%
	Human Resource Outsourcing		46	%	2	%	0	%	44	%
		Total Consulting	16	%	2	%	0	%	14	%
Insurance Underwriting:
	Accident & Health and Life		16	%	4	%	4	%	8	%
	Warranty, Credit and Property & Casualty		7	%	2	%	0	%	5	%
		Total Insurance Underwriting	12	%	3	%	2	%	7	%
Total Operating Segments			17	%	3	%	-1	%	15	%

			4th Quarter 2002
			Reported Revenue Growth		Less: Currency Impact		Less: All Other (1)		Organic Revenue Growth
Risk & Insurance Brokerage Services:
	Risk Management & Insurance Brokerage—Americas		5	%	-1	%	-5	%	11	%
	Risk Management & Insurance Brokerage—International		23	%	9	%	2	%	12	%
	Reinsurance Brokerage & Related Services		28	%	2	%	5	%	21	%
	Claims Services		-1	%	2	%	-1	%	-2	%
		Total Risk & Insurance Brokerage Services	13	%	3	%	0	%	10	%
Consulting:
	Benefits, Compensation, Management and Communications Consulting		8	%	2	%	1	%	5	%
	Human Resource Outsourcing		42	%	2	%	3	%	37	%
		Total Consulting	15	%	2	%	1	%	12	%
Insurance Underwriting:
	Accident & Health and Life		6	%	4	%	-9	%	11	%
	Warranty, Credit and Property & Casualty		6	%	4	%	7	%	-5	%
		Total Insurance Underwriting	6	%	4	%	-2	%	4	%
Total Operating Segments			11	%	3	%	-1	%	9	%

			Full Year 2002
			Reported Revenue Growth		Less: Currency Impact		Less: All Other (1)		Organic Revenue Growth
Risk & Insurance Brokerage Services:
	Risk Management & Insurance Brokerage—Americas		10	%	-1	%	-2	%	13	%
	Risk Management & Insurance Brokerage—International		20	%	4	%	2	%	14	%
	Reinsurance Brokerage & Related Services		18	%	1	%	-6	%	23	%
	Claims Services		6	%	1	%	1	%	4	%
		Total Risk & Insurance Brokerage Services	14	%	1	%	0	%	13	%
Consulting:
	Benefits, Compensation, Management and Communications Consulting		8	%	1	%	1	%	6	%
	Human Resource Outsourcing		30	%	1	%	7	%	22	%
		Total Consulting	12	%	1	%	2	%	9	%
Insurance Underwriting:
	Accident & Health and Life		15	%	1	%	-2	%	16	%
	Warranty, Credit and Property & Casualty		6	%	1	%	0	%	5	%
		Total Insurance Underwriting	11	%	1	%	-1	%	11	%
Total Operating Segments			13	%	1	%	0	%	12	%

(1)

Includes items discussed in the organic revenue growth description, beyond currency impact.

AON CORPORATION
RECONCILIATION OF REPORTED REVENUE GROWTH TO ORGANIC REVENUE GROWTH

			1st Quarter 2001
			Reported Revenue Growth		Less: Currency Impact		Less: All Other (1)		Organic Revenue Growth
Risk & Insurance Brokerage Services:
	Risk Management & Insurance Brokerage—Americas		1	%	-1	%	2	%	0	%
	Risk Management & Insurance Brokerage—International		1	%	-7	%	0	%	8	%
	Reinsurance Brokerage & Related Services		12	%	-4	%	-2	%	18	%
	Claims Services		32	%	-3	%	-11	%	46	%
		Total Risk & Insurance Brokerage Services	5	%	-4	%	1	%	8	%
Consulting:
	Benefits, Compensation, Management and Communications Consulting		18	%	-3	%	10	%	11	%
	Human Resource Outsourcing		30	%	-4	%	36	%	-2	%
		Total Consulting	20	%	-4	%	16	%	8	%
Insurance Underwriting:
	Accident & Health and Life		9	%	-3	%	4	%	8	%
	Warranty, Credit and Property & Casualty		5	%	-3	%	7	%	1	%
		Total Insurance Underwriting	7	%	-3	%	5	%	5	%
Total Operating Segments			7	%	-4	%	4	%	7	%

			2nd Quarter 2001
			Reported Revenue Growth		Less: Currency Impact		Less: All Other (1)		Organic Revenue Growth
Risk & Insurance Brokerage Services:
	Risk Management & Insurance Brokerage—Americas		5	%	-1	%	0	%	6	%
	Risk Management & Insurance Brokerage—International		3	%	-7	%	1	%	9	%
	Reinsurance Brokerage & Related Services		15	%	-4	%	-4	%	23	%
	Claims Services		48	%	-2	%	-1	%	51	%
		Total Risk & Insurance Brokerage Services	9	%	-3	%	0	%	12	%
Consulting:
	Benefits, Compensation, Management and Communications Consulting		23	%	-2	%	15	%	10	%
	Human Resource Outsourcing		45	%	-4	%	43	%	6	%
		Total Consulting	27	%	-3	%	21	%	9	%
Insurance Underwriting:
	Accident & Health and Life		10	%	-3	%	5	%	8	%
	Warranty, Credit and Property & Casualty		-11	%	-3	%	-1	%	-7	%
		Total Insurance Underwriting	0	%	-3	%	2	%	1	%
Total Operating Segments			7	%	-3	%	2	%	8	%

			3rd Quarter 2001
			Reported Revenue Growth		Less: Currency Impact		Less: All Other (1)		Organic Revenue Growth
Risk & Insurance Brokerage Services:
	Risk Management & Insurance Brokerage—Americas		-2	%	-1	%	1	%	-2	%
	Risk Management & Insurance Brokerage—International		7	%	-4	%	4	%	7	%
	Reinsurance Brokerage & Related Services		7	%	-2	%	5	%	4	%
	Claims Services		48	%	-1	%	0	%	49	%
		Total Risk & Insurance Brokerage Services	6	%	-2	%	2	%	6	%
Consulting:
	Benefits, Compensation, Management and Communications Consulting		22	%	-1	%	17	%	6	%
	Human Resource Outsourcing		53	%	-3	%	57	%	-1	%
		Total Consulting	27	%	-2	%	25	%	4	%
Insurance Underwriting:
	Accident & Health and Life		8	%	-4	%	2	%	10	%
	Warranty, Credit and Property & Casualty		8	%	1	%	1	%	6	%
		Total Insurance Underwriting	8	%	-2	%	2	%	8	%
Total Operating Segments			9	%	-2	%	4	%	7	%

			4th Quarter 2001
			Reported Revenue Growth		Less: Currency Impact		Less: All Other (1)		Organic Revenue Growth
Risk & Insurance Brokerage Services:
	Risk Management & Insurance Brokerage—Americas		6	%	-1	%	7	%	0	%
	Risk Management & Insurance Brokerage—International		13	%	0	%	3	%	10	%
	Reinsurance Brokerage & Related Services		-6	%	0	%	-19	%	13	%
	Claims Services		47	%	0	%	2	%	45	%
		Total Risk & Insurance Brokerage Services	9	%	0	%	0	%	9	%
Consulting:
	Benefits, Compensation, Management and Communications Consulting		6	%	-1	%	-1	%	8	%
	Human Resource Outsourcing		62	%	2	%	56	%	4	%
		Total Consulting	14	%	0	%	7	%	7	%
Insurance Underwriting:
	Accident & Health and Life		6	%	0	%	-10	%	16	%
	Warranty, Credit and Property & Casualty		-1	%	1	%	-3	%	1	%
		Total Insurance Underwriting	3	%	0	%	-5	%	8	%
Total Operating Segments			8	%	0	%	-1	%	9	%

			Full Year 2001
			Reported Revenue Growth		Less: Currency Impact		Less: All Other (1)		Organic Revenue Growth
Risk & Insurance Brokerage Services:
	Risk Management & Insurance Brokerage—Americas		3	%	-1	%	3	%	1	%
	Risk Management & Insurance Brokerage—International		6	%	-4	%	1	%	9	%
	Reinsurance Brokerage & Related Services		7	%	-2	%	-5	%	14	%
	Claims Services		44	%	-2	%	-1	%	47	%
		Total Risk & Insurance Brokerage Services	7	%	-2	%	0	%	9	%
Consulting:
	Benefits, Compensation, Management and Communications Consulting		16	%	-1	%	8	%	9	%
	Human Resource Outsourcing		48	%	-2	%	48	%	2	%
		Total Consulting	22	%	-2	%	17	%	7	%
Insurance Underwriting:
	Accident & Health and Life		8	%	-3	%	0	%	11	%
	Warranty, Credit and Property & Casualty		0	%	-1	%	1	%	0	%
		Total Insurance Underwriting	4	%	-2	%	1	%	5	%
Total Operating Segments			8	%	-2	%	2	%	8	%

(1)

Includes items discussed in the organic revenue growth description, beyond currency impact.

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AON CORPORATION RECONCILIATION OF REPORTED REVENUE GROWTH TO ORGANIC REVENUE GROWTH

EX-99.5

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Exhibit 99.5

AON CORPORATION
SEGMENTS AS RECLASSIFIED—EXCLUDING PREVIOUSLY REPORTED SPECIAL & UNUSUAL CHARGES

			2002															2003
			1st Qtr.			2nd Qtr.			3rd Qtr.			4th Qtr.			Full Year			1st Qtr.
			(millions)
REVENUE
	Risk & Insurance Brokerage Services		$	1,157		$	1,215		$	1,247		$	1,354		$	4,973		$	1,374
	Consulting			233			248			269			304			1,054			282
	Insurance Underwriting			649			750			718			684			2,801			709
	Corporate & Other			49			(91	)		12			24			(6	)		35
	Intersegment Revenues			—			—			—			—			—			(12	)
		Total Revenue	$	2,088		$	2,122		$	2,246		$	2,366		$	8,822		$	2,388
INCOME (LOSS) BEFORE INCOME TAXES
	Risk & Insurance Brokerage Services		$	189		$	138		$	191		$	238		$	756		$	230
	Consulting			27			23			26			44			120			20
	Insurance Underwriting			73			5			41			44			163			63
	Corporate & Other			(13	)		(153	)		(59	)		(48	)		(273	)		(20	)
		Total Income Before Income Taxes	$	276		$	13		$	199		$	278		$	766		$	293
INCOME BEFORE INCOME TAXES—MARGINS
	Risk & Insurance Brokerage Services			16.3	%		11.4	%		15.3	%		17.6	%		15.2	%		16.7	%
	Consulting			11.6	%		9.3	%		9.7	%		14.5	%		11.4	%		7.1	%
	Insurance Underwriting			11.2	%		0.7	%		5.7	%		6.4	%		5.8	%		8.9	%
		Total Income Before Income Taxes—Margins		13.2	%		0.6	%		8.9	%		11.7	%		8.7	%		12.3	%

AON CORPORATION
SEGMENTS AS RECLASSIFIED—EXCLUDING PREVIOUSLY REPORTED SPECIAL & UNUSUAL CHARGES

			2001
			1st Qtr.			2nd Qtr.			3rd Qtr.			4th Qtr.			Full Year
			(millions)
REVENUE
	Risk & Insurance Brokerage Services		$	1,052		$	1,083		$	1,030		$	1,198		$	4,363
	Consulting			212			229			232			265			938
	Insurance Underwriting			628			609			641			643			2,521
	Corporate & Other			(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		$	198		$	190		$	150		$	193		$	731
	Consulting			25			30			29			49			133
	Insurance Underwriting			69			83			90			85			327
	Corporate & Other			(172	)		(93	)		(83	)		(158	)		(506	)
		Total Income Before Income Taxes	$	120		$	210		$	186		$	169		$	685
INCOME BEFORE INCOME TAXES—MARGINS
	Risk & Insurance Brokerage Services			18.8	%		17.5	%		14.6	%		16.1	%		16.8	%
	Consulting			11.8	%		13.1	%		12.5	%		18.5	%		14.2	%
	Insurance Underwriting			11.0	%		13.6	%		14.0	%		13.2	%		13.0	%
		Total Income Before Income Taxes—Margins		6.6	%		11.0	%		9.7	%		8.3	%		8.9	%

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AON CORPORATION SEGMENTS AS RECLASSIFIED—EXCLUDING PREVIOUSLY REPORTED SPECIAL & UNUSUAL CHARGES