Aon (AON) 8-K Regulation FD Disclosure

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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