J., APEX Management Group, a
healthcare, insurance services and actuarial consulting firm, announced today
the promotion of Timothy Robinson, FSA, MAAA to chief actuary., is a leading healthcare, insurance services and
actuarial consultancy, primarily serving reinsurers, health plans and employer
groups. It
should be viewed in addition to, not in lieu of, the Company's Consolidated
Summary of Operations.59 $0.54 9 % $1.01) (0.5 337.1% and 36% for the six months
ended June 30, 2005 and 2004, respectively .

Aon First Quarter Net Income Increases 18% to $200 Million; Earnings Per Share Increases 16% to $0.59

Organic revenue growth in consulting services was 2%,
while outsourcing revenues declined 11 %, primarily reflecting the loss of a
large client.

Aon Corporation ( http://www.

horizontally perrin

Net income from continuing
operations and the related per share amounts for six months increased to $393
million or $1.17 from $372 million or $1. We were encouraged by the progress of U.0% from 15 .
The pretax loss in the Corporate and Other segment was $51 million
compared with a loss of $32 million a year ago, principally driven by equity
earnings on Endurance common stock of $18 million in 2004. The reduction in
the tax rate for both the first quarter and six months 2005 is attributable to
the resolution of tax issues which had a net favorable impact of $6 million.
Stockholders' equity was $5.
Approximately 94% of Aon's investment portfolio at quarter end was in
short -term and fixed maturities, with 97% of the fixed income securities rated
investment grade.
The Company will host an audio webcast on Wednesday, August 3 at 10:00
a. Industry peers provide similar supplemental
information regarding their revenue performance, although they do not make
identical adjustments.03 13 %
====== ====== ===== ====== ====== =====
Diluted average common
and common equivalent
shares outstanding
(2) 338.
Gregory C.
Consulting revenue rose 3% to $309 million during the quarter.
The Company will host an audio webcast on Wednesday, May 4 at 10:00 a.

saa profitability

Robinson has more than 14 years of experience in the health care actuarial
field. Prior to joining APEX in 2000, Robinson was vice president and chief
actuary for Avandel Inc."
Robinson, 37, is a resident of Princeton Junction, NJ.
Organic revenue in Brokerage-Americas declined 2%, primarily driven by the
loss of contingent commissions and the impact of declining property and
casualty pricing . Excluding the impact of contingent commissions, Brokerage-
Americas organic revenue grew 3%.

Consulting revenue rose 3% to $315 million during the quarter. Potential factors that could impact
results include: general economic conditions in different countries in which
we do business around the world, changes in global equity and fixed income
markets that could affect the return on invested assets, fluctuations in
exchange and interest rates that could influence revenue and expense, rating
agency actions that could affect our ability to borrow funds, funding of our
various pension plans , changes in the competitive environment, our ability to
implement restructuring initiatives and other initiatives intended to yield
cost savings, changes in commercial property and casualty markets and
commercial premium rates that could impact revenues, changes in revenues and
earnings due to the elimination of contingent commissions, other uncertainties
surrounding a new compensation model, the impact of investigations brought by
state attorneys general, state insurance regulators, federal prosecutors, and
federal regulators, the impact of class actions and individual lawsuits
including client class actions, securities class actions, derivative actions,
and ERISA class actions, the cost of resolution of other contingent
liabilities and loss contingencies, and the difference in ultimate paid claims
in our underwriting companies from actuarial estimates.

Aon Corporation
Segments - Year-to-date Continuing Operations

Six Months Ended
--------------------------------------------------------------------------

Organic
Revenue
Growth
Less: exclu-
Acquis- ding
itions, Less: Organic Contin-
June 30, Less: Divest- All Revenue gent
June 30, 2004 Percent Currency itures+ Other Growth Commis-
(millions) 2005 (1) Change Impact Transfers (2) (3) sions
------- ----- ------- ------- -------- ----- ------ -------
Revenue
Risk and insurance
brokerage
services
Risk management
and insurance
brokerage -
Americas $1,100 $1,128 (2)% 1% 1% 1% (5)% -%
Risk management
and insurance
brokerage -
International 1,252 1,207 4 4 1 - (1) -
Reinsurance
brokerage and
related
services 443 443 - 2 - 3 (5) (5)
Claims services - 118 (100) - (100) - - -
---- ---- ---- ---- ---- ---- ---- ----
Total risk and
insurance
brokerage
services 2,795 2,896 (3) 3 (4) 1 (3) (1)
---- ---- ---- ---- ---- ---- ---- ----
Consulting
Consulting
services 484 455 6 2 3 (1) 2 5
Outsourcing 140 151 (7) 1 - 1 (9) (9)
---- ---- ---- ---- ---- ---- ---- ----
Total
consulting 624 606 3 2 2 - (1) 1
---- ---- ---- ---- ---- ---- ---- ----
Insurance
underwriting
Accident +
health and
life 890 866 3 2 - (2) 3 3
Warranty , credit
and property +
casualty 715 720 (1) 2 - 4 (7) (7)
---- ---- ---- ---- ---- ---- ---- ----
Total insurance
under-
writing 1,605 1,586 1 2 - 1 (2) (2)
---- ---- ---- ---- ---- ---- ---- ----

Corporate and other 35 54 (35) N/A N/A N/A N/A N/A

Intersegment
revenues (30) (34) N/A N/A N/A N/A N/A N/A
- --- ---- ---- ---- ---- ---- ---- ----
Total $5,029 $5,108 (2)% 2 % (2)% 1% (3)% (1)%
====== ====== ==== ==== ==== ==== ==== ====
Investment income
(included in
Revenue above)
Risk and
insurance
brokerage
services $57 $32 78%
Consulting 2 1 100
Insurance
underwriting 75 63 19
Corporate and
other 35 54 (35)
---- ---- -----
Total $169 $150 13%
==== ==== =====

Income (loss) from
continuing
operations before
provision for
income tax
Risk and
insurance
brokerage
services $474 $456 4%
Consulting 55 54 2
Insurance
underwriting 151 126 20
Corporate and
other (75) (54) N/A
---- ---- -----
Total $605 $582 4%
==== ==== =====

Income from
continuing
operations before
provision for
income tax -
margins
Risk and
insurance
brokerage
services 17.58 per share a year ago. During the quarter, we continued our efforts to keep costs under
control and to develop new sources of revenue.8% for 2004, reflecting improved
profitability in both underwriting subsegments and higher investment income.1 billion at
March 31, 2005 from March 31, 2004. 31, Mar.

higham profitability

Second quarter 2005 net income and the related per share amount increased
10% to $191 million or $0.
Six months 2005 net income of $391 million or $1. Excluding the loss of
contingent commissions, organic revenue in the current quarter rose 1%.4% from 7. Total debt and preferred stock as a
percentage of total capital was reduced to 27% from 31% over the same period.16 $1.2% 9. Income
from continuing operations was $200 million or $0. These changes had no impact on
organic revenue growth or pretax income.

Investor Contact: Craig Streem
Corporate Vice President, Investor Relations
312-381-3983

Media Contact: Al Orendorff
Director, Public Relations
312-381-3153

Aon Corporation
Consolidated Summary of Operations

First Quarter Ended
--------------------------------
Mar.07) N/A
------- ------- -------
Net income $0. Mar.

niis wyatt

Greg Case, Aon's president and CEO, said, "Our second quarter results show
ongoing improvement, and we are pleased with our performance despite the
continued decline in insurance premium rates and our decision to terminate
contingent commission arrangements. Backed by
broad resources, industry knowledge and technical expertise, Aon professionals
help a wide range of clients develop effective risk management and workforce
productivity solutions. Further information
concerning the Company and its business , including factors that potentially
could materially affect the Company's financial results, is contained in the
Company's filings with the Securities and Exchange Commission.1%

(1) Certain amounts relating to discontinued operations have been
reclassified to conform to the 2005 presentation.
Written premiums and fees are the basis for organic revenue growth
within the Insurance Underwriting segment. Contingent
commission revenue was $12 million in the first quarter of 2005, reflecting
amounts related to arrangements terminated as of October 1 , 2004.4% from 16.aon.

profitability perrin

PRINCETON, N.54 per share a year ago. Excluding the loss of contingent commissions ,
organic revenue rose 3% in the current quarter reflecting growth in U. Contingent commission revenue was $1 million in the
second quarter of 2005 compared with $11 million in the second quarter of
2004 . The pretax margin improved to
10.
Six months pretax income increased 20% to $151 million and the pretax
margin improved to 9.3 billion.57 $0.4% versus 8. In addition, strong growth in the
sales of a supplemental health product was partially offset by planned
reductions in certain programs and the run-off of non-core businesses. Potential factors that could impact
results include: general economic conditions in different countries in which
we do business around the world, changes in global equity and fixed income
markets that could affect the return on invested assets, fluctuations in
exchange and interest rates that could influence revenue and expense, rating
agency actions that could affect our ability to borrow funds, funding of our
various pension plans, changes in the competitive environment, changes in
commercial property and casualty markets and commercial premium rates that
could impact revenues, changes in revenues and earnings due to the elimination
of contingent commissions, other uncertainties surrounding a new compensation
model, the impact of regulatory investigations brought by state attorneys
general and state insurance regulators related to our compensation
arrangements with underwriters and related issues, the impact of class actions
and individual lawsuits including client class actions, securities class
actions, derivative actions, and ERISA class actions, the cost of resolution
of other contingent liabilities and loss contingencies, and the difference in
ultimate paid claims in our underwriting companies from actuarial estimates.

higham policyholders

retail, a 4% reduction in expenses
largely reflecting the exit of the claims services business, changes to
incentive compensation programs, and continued emphasis on cost control.9% in 2004. 36%, respectively.aon.
This press release includes supplemental information related to organic
revenue growth, a measure that management believes is important to evaluate
changes in revenue from existing operations. We also believe that this
supplemental information is helpful to investors.59 per share,
increasing 18% and 16%, respectively, from the first quarter of 2004. Case, Aon's President and CEO, stated, "I am encouraged that
Aon achieved improved results in the first quarter despite a difficult revenue
environment in the insurance brokerage and human resources consulting
industries and despite our decision to eliminate contingent commissions last
year."

First Quarter Segment Review
Risk and Insurance Brokerage Services first quarter revenue declined 4% to
$1.4 billion, with organic revenue declining 5%.6% from 6.
(2) In accordance with EITF 04-08, the diluted net income per share
calculations for the first quarters ended March 31,
2005 and 2004 include 14 million additional shares related to the
potential conversion of 3.

horizontally netpay

57 per share from the second quarter of 2004.9% a year ago.com . These forward-looking
statements are subject to certain risks and uncertainties that could cause
actual results to differ materially from either historical or anticipated
results depending on a variety of factors.56 7 % $1.07 13 %
====== ====== ===== ====== ====== ======

Diluted net income per
share:
Income from
continuing
operations $0.9%
Insurance
underwriting 9. Excluding contingent commissions, organic
revenue growth was nil in the current quarter. The
pretax margin improved to 8. In addition, first
quarter 2005 and 2004 earnings per share included $0.58 2 %
Discontinued operations - (0. 31, Mar. 31, Percent
2005 2004 Change
-------- -------- -------
(1) Includes (millions):
Income from Endurance warrants $16 $4 300 %
Equity earnings - Endurance - 16 (100)
-------- -------- -------
Total $16 $20 (20)%
======== ======== =======
(2) Includes gain on sale of
Endurance stock (millions ) $- $11 (100)%

perrin netpay

, where he was responsible for all actuarial and data
analysis.5% from 14. employee benefits.

(2) In accordance with EITF 04-08, the diluted net income per share
calculations for the second quarters and six months ended June 30,
2005 and 2004 include 14 million additional shares related to the
potential conversion of our 3.1% and 36% for the second quarters ended June 30, 2005
and 2004, respectively , and 35.
Pretax income was $26 million, unchanged from the prior year, and the
pretax margin was 8. Compared
to December 31, 2004, total debt and preferred stock decreased $30 million.m.
central time that can be accessed at http://www.com .
Written premiums and fees are the basis for organic revenue growth
within the Insurance Underwriting segment.

intermediary broking

S.S.
Written premiums and fees are the basis for organic revenue growth
within the Insurance Underwriting segment. Organic revenue growth
excludes from reported revenues the impact of foreign exchange, acquisitions,
divestitures, transfers between business units, investment income,
reimbursable expenses, unusual items, and for the underwriting segment only,
an adjustment between written and earned premium.60 3 %
Discontinued operations - (0.1 335. Less: Divestitures All Revenue
31, 31, Percent Currency + Other Growth
(millions) 2005 2004 (1) Change Impact Transfers (2) (3)
------ ------ ------ ------ ------- ------ ------

Revenue
-------
Risk and
insurance
brokerage
services
Risk
management
and insurance
brokerage
- Americas $499 $531 (6)% 1% 1% 1% (9)%
Risk
management
and insurance
brokerage -
International 660 633 4 4 2 (1) (1)
Reinsurance
brokerage
and related
services 240 239 - 2 - 2 (4)
Claims
services - 61 (100) - (100) - -
------ ------ ------ ------ ------- ------ ------
Total risk
and
insurance
brokerage
services 1,399 1,464 (4) 2 (3) 2 (5)
------ ------ ------ ------ ------- ------ ------
Consulting
Consulting
services 240 225 7 2 2 1 2
Outsourcing 69 76 (9) 1 - 1 (11)
------ ------ -- ---- ------ ------- ------ ------
Total
consulting 309 301 3 2 2 - (1)
------ ------ ------ ------ ------- ------ ------
Insurance
underwriting
Accident +
health and
life 440 425 4 2 - - 2
Warranty,
credit and
property +
casualty 349 356 (2) 1 - 4 (7)
------ ------ ------ ------ ------- ------ ------
Total
insurance
under-
writing 789 781 1 2 - 2 (3)
------ ------ ------ ------ ------- ------ ------
Corporate
and other 29 36 (19) N/A N/A N /A N/A

Intersegment
revenues (15) (18) N/A N/A N/A N/A N/A
------ ------ ------ ------ ------- ------ ------
Total $2,511 $2,564 (2)% 2% (2)% 2% (4)%
====== ====== ====== ====== ======= ====== ======

Investment
income
(included
in
Revenue
above)
----------
Risk and
insurance
brokerage
services $27 $14 93%
Consulting 1 - N /A
Insurance
underwriting 36 31 16
Corporate
and other 29 36 (19)
------ ------ ------
Total $93 $81 15%
====== ====== ======

Income (loss)
from
continuing
operations
before
income tax
------------
Risk and
insurance
brokerage
services $243 $243 -%
Consulting 26 26 -
Insurance
underwriting 68 53 28
Corporate
and other (24) (22) N/A
------ ------ ------
Total $313 $300 4%
====== ====== ======

Income from
continuing
operations
before
income tax
- margins
------- -----
Risk and
insurance
brokerage
services 17.

All agency , brokerage, and marketing sites that market to consumers should be submitted to the appropriate sub -category of Agents and Marketers

saa expense

He is a Fellow of
the Society of Actuaries and serves on the American Academy of Actuaries Work
Groups for Disease Management and Medical Reinsurance. degree in Mathematics."
As the Company continues to refine its plans to improve operational focus
and reduce its cost base, it is possible that we may identify additional
opportunities that could result in additional charges and potential cost-
savings.
Pretax income increased 8% to $231 million , and the pretax margin improved to
16. and
U.m.

Aon Corporation ( http://www.01) (0.21 $1.01) (0.
(2) Includes the impact of investment income, reimbursable expenses,
adjustment between written and earned premium and fees in insurance
underwriting only, and unusual items.
(3) Organic revenue growth excludes the impact of foreign exchange,
acquisitions, divestitures, transfers and items described in (2).5% Senior Convertible
Debentures.6%
Insurance
underwriting 8.7%

(1) Certain amounts relating to discontinued operations have been
reclassified to conform to the 2005 presentation .

higham casualty

7%.
The pretax loss for six months was $75 million compared to a pretax loss
of $54 million a year ago.

Foreign Exchange Impact
Second quarter 2005 earnings per share were positively affected by $0.02
related to foreign currency translation gains. In addition, both second
quarter 2005 and 2004 earnings per share included $0. central time that can be accessed at http://www.54 7 % $1.09) N/A
------ ------ ----- ------ ------ ---- -
Net income $0.
Stockholders' equity was $5. It
should be viewed in addition to, not in lieu of, the Company's Consolidated
Summary of Operations.62 $0.

aam casualty

In his new position, Robinson will oversee actuarial work and product
development as well as lead training development and peer review of actuaries. Olaf College, with a B.16 per share increased
14% and 13%, respectively , from the prior period."
Case added, "While we are clearly making progress, our aspirations are
very high. To ensure that we
deliver continuous improvements, we are reviewing the revenue potential and
cost structure of each of our businesses.
Contingent commission revenue was $4 million in the second quarter of 2005,
reflecting amounts collected during the quarter relating to arrangements
terminated as of October 1, 2004.8% versus 8.

Insurance Underwriting revenue increased 1% to $816 million, while organic
revenue declined 2% during the quarter. A reconciliation is
provided in the attached schedules. Excluding contingent
commissions, organic revenue in the current quarter declined 3%. Investment
income increased $13 million in the quarter.6% in 2004.
The pretax loss in the quarter was $24 million compared with a loss of
$22 million a year ago.

Foreign Exchange Impact
First quarter 2005 earnings per share were positively affected by
$0.

underwriting sbj

12, respectively .
Second quarter results also benefited from continued tight management of our
cost base, which is a central component of our program to improve Aon's
profitability.
Pretax income rose 4 % to $29 million, and the pretax margin was 9. Organic revenue growth
excludes from reported revenues the impact of foreign exchange, acquisitions,
divestitures, transfers between business units, investment income,
reimbursable expenses, unusual items, and for the underwriting segment only,
an adjustment between written and earned premium.17 $1.9%
Total 12.0% 11.
Organic revenue in Brokerage-Americas declined 9%, primarily driven by the
elimination of contingent commissions and the impact of declining property and
casualty pricing.
Pretax income was $243 million, unchanged from the prior year, and the pretax
margin improved to 17.

This press release includes supplemental information related to organic
revenue growth, a measure that management believes is important to evaluate
changes in revenue from existing operations. A reconciliation is
provided in the attached schedules.

niis fries

"He has continually demonstrated his dedication and
commitment to clients and our staff. We also anticipate that these initiatives will lead to
annualized cost-savings ranging from $100 million to $150 million. Investment income
increased $12 million in the quarter compared to the prior year, primarily
reflecting higher short-term interest rates.

This press release contains certain statements related to future results,
or states our intentions, beliefs and expectations or predictions for the
future which are forward-looking statements as that term is defined in the
Private Securities Litigation Reform Act of 1995.60 $0.02) N/A (0. Contingent commission revenue
was negligible in the first quarter of 2005 compared to $4 million in the
first quarter of 2004.1 billion, unchanged from year-end 2004.aon.59 $0.4% 8.8%
Total 12 .

reinsurance expense

APEX Management Group Promotes Timothy Robinson to Chief Actuary

"Tim has made significant contributions to the growth and success of our
firm over the past four years," said Don Gasparro , president of APEX
Management Group. He is a 1989 graduate
of St.

Aon Second Quarter Net Income Increases 10% to $191 Million; Earnings Per Share Increases 10% to $0.57

CHICAGO, Aon Corporation (NYSE: AOC)
today reported second quarter and six months 2005 results.
retail brokerage, employee benefits consulting, and insurance underwriting. We are committed to achieving optimal performance and generating
attractive returns irrespective of market influences.2% for
both 2005 and 2004 .2% from 9.1% for 2004, reflecting improved profitability in both
underwriting subsegments and higher investment income.1% for the second
quarter 2005 compared to 36% for the second quarter of 2004.

The year-to-date
tax rate for 2005 and 2004 was 35.01) (0.52 10 % $1.

(3) Tax rate is 34.6% 11.0% 15.
(2) Includes the impact of investment income, reimbursable expenses ,
adjustment between written and earned premium and fees in insurance
underwriting only, and unusual items.
Pretax income rose 28% to $68 million from $53 million last year.4% 16.

This category is for consulting firms that provide support services to the insurance industry.

expense jcg

Net
income from continuing operations increased to $193 million or $0. Compared to December 31 , 2004, total
debt and preferred stock decreased $265 million.aon. Contingent
commission revenue was $35 million in the first quarter of 2004. Brokerage-International reported a
1% decline in organic revenue, and Reinsurance organic revenue declined 4%.03,
respectively, of currency hedging gains .
Approximately 94% of Aon's investment portfolio at quarter end was in
short-term and fixed maturities, with 97% of the fixed income securities rated
investment grade.
(2) Includes the impact of investment income, reimbursable expenses,
adjustment between written and earned premium and fees in insurance
underwriting only, and unusual items. 31, Percent
(millions) 2005 2004 Change
-------- -------- -------
Revenue
-------
Income from marketable equity
securities and other investments (1) $24 $22 9 %
Limited partnership investments 1 4 (75)
Net gain on disposals and related
expenses (2) 4 10 (60)
-------- -------- -------
Total revenue 29 36 (19)
-------- -------- -------

Expenses
--------
General expenses 19 24 (21)
Interest expense 34 34 -
-------- -------- -------
Total expenses 53 58 (9)
--- ----- -------- -------

Loss before income tax $(24) $(22) N/A %
======== ======== =======

Notes:

First Quarter Ended
-------------------------------
Mar.

saa perrin

The decline in warranty, credit and property and casualty organic revenue
principally reflected returned premiums on a Japanese program and the earlier
loss of an account within the European credit insurance business, with minimal
impact on pretax income.16 5 %
Discontinued
operations (0.58 $0.5% Senior Convertible Debentures.7%
Consulting 8.6% a year ago. Organic
revenue declined 1%, reflecting the loss of contingent commissions and a
decline in outsourcing revenue. The
decline in warranty, credit and property and casualty revenue principally
reflected the loss of an account within the European credit line of business
that had minimal impact on pretax income.02 and $0.
Backed by broad resources, industry knowledge and technical expertise, Aon
professionals help a wide range of clients develop effective risk management
and workforce productivity solutions.
Further information concerning the Company and its business, including factors
that potentially could materially affect the Company's financial results, is
contained in the Company's filings with the Securities and Exchange
Commission. We also believe that this
supplemental information is helpful to investors.3 1 %
======= ======= =======

(1) Certain amounts relating to discontinued operations have been
reclassified to conform to the 2005 presentation . In addition, the net income used in the calculation
includes after-tax interest expense of approximately
$1 million for the first quarters ended March 31, 2005 and 2004.

saa aam

Princeton, NJ-based APEX Management Group, a division of Gallagher
Benefits Services, Inc. Excluding the effect of contingent
commissions, organic revenue increased in both the Risk + Insurance Brokerage
Services and Consulting segments.
Second quarter 2005 pretax income and margin comparisons were favorably
influenced by improved retention in U.S.
Six months pretax income increased 2% to $55 million and the pretax margin
was 8.

Effective Tax Rate
The effective tax rate for continuing operations was 34.1% vs.

Aon Corporation
Consolidated Summary of Operations

Second Quarter Ended Six Months Ended
-------------------------- -------------------------
(millions except per June 30, June 30, Percent June 30, June 30, Percent
share data) 2005 2004 (1) Change 2005 2004(1) Change
-------------------------- ----- --------------------
Revenue
Brokerage commissions
and fees $1,724 $1,759 (2)% $3,444 $3,550 (3)%
Premiums and other 718 716 - 1,416 1,408 1
Investment income 76 69 10 169 150 13
------ ------ ----- ------ ----- -----
Total revenue 2,518 2,544 (1) 5,029 5,108 (2)
------ ------ ----- ------ ----- -----
Expenses
General expenses 1,750 1,752 - 3,452 3,529 (2)
Benefits to
policyholders 381 392 (3 ) 774 775 -
Depreciation and
amortization 62 83 (25) 130 153 (15)
Interest expense 31 35 (11) 65 69 (6)
Provision for New
York and other state
settlements 2 - N/A 3 - N/A
----- ----- ---- ----- ----- ----
Total expenses 2,226 2,262 (2) 4,424 4,526 (2 )
----- ----- ---- ----- ----- ----
Income from continuing
operations before
provision for income
tax 292 282 4 605 582 4
Provision for income
tax (3) 99 102 (3) 212 210 1
----- ----- ---- - --- ---- ----
Income from continuing
operations 193 180 7 393 372 6

Loss from discontinued
operations, net of
tax (2) (7) N/A (2) (29) N/A
- ---- ----- ----- ----- ----- -----

Net income $191 $173 10 % $391 $343 14 %
===== ===== ===== ===== ===== =====
Preferred stock
dividends - - - (1) (1) -
----- ----- ----- ----- ----- -----
Net income available
for common
stockholders $191 $173 10 % $390 $342 14 %
===== ===== ===== ===== ===== =====

Basic net income per share:
Income from
continuing
operations $0.09) N/A
------ ------ ----- ------ ------ ------
Net income $0.4%

(1) Certain amounts relating to discontinued operations have been
reclassified to conform to the 2005 presentation. 31, Percent
(millions except per share data) 2005 2004 (1) Change
------- -------- -------
Revenue
-------
Brokerage commissions and fees $1,720 $1,791 (4)%
Premiums and other 698 692 1
Investment income 93 81 15
------- ------- -------
Total revenue 2,511 2,564 (2)
------- ------- -------

Expenses
--------
General expenses 1,702 1,777 (4)
Benefits to policyholders 393 383 3
Depreciation and amortization 68 70 (3)
Interest expense 34 34 -
Provision for New York and other
state settlements 1 - N/A
------- ------- --- ----
Total expenses 2,198 2,264 (3)

Income from continuing operations
before provision for income tax 313 300 4
Provision for income tax (36% in
2005 and 2004) 113 108 5
------- ------- -------
Income from continuing operations 200 192 4

Loss from discontinued operations, net
of tax - (22) N/A
------- ------- -------

Net income $200 $170 18 %
======= ======= =======
Preferred stock dividends (1) (1) -
------- ------- -------
Net income available for common
stockholders $199 $169 18 %
======= ======= =======

Basic net income per share:
Income from continuing operations $0.

Aon Corporation
Segments - First Quarter Continuing Operations

First Quarter Ended
------------------ ----------------------------------------
Less:
Acquisitions, Less: Organic
Mar.6% 6.
(3) Organic revenue growth excludes the impact of foreign exchange,
acquisitions, divestitures, transfers and items described in (2).

profitability higham

9 billion at
June 30, 2005 from June 30, 2004.com ) is a leading provider of risk
management services, insurance and reinsurance brokerage, human capital and
management consulting, and specialty insurance underwriting. There are 47,000
employees working in Aon's 500 offices in more than 120 countries.22 $1. Reported revenue in the
quarter included a $12 million increase due to reinsurance program changes for
a specialty accident and health (A+H) line.com ) is a leading provider of risk
management services , insurance and reinsurance brokerage, human capital and
management consulting, and specialty insurance underwriting. The supplemental organic revenue growth
information does not affect net income or any other GAAP reported amounts.53 17 %
======= ======= =======

Diluted net income per share:
Income from continuing operations $0.59 $0.51 16 %
======= ======= =======

Diluted average common and common
equivalent shares outstanding (2) 337.

Aon Corporation
Corporate and Other - Continuing Operations

First Quarter Ended
------------------------------
Mar .

sbj underwriting

Robinson
previously held the position of consulting actuary at APEX, a division of
Gallagher Benefits Services, Inc.
Six months pretax income increased 4% to $474 million and the pretax
margin improved 130 basis points to 17.
Pretax income rose 14% to $83 million.4% 7.

Aon Corporation
Corporate and Other - Continuing Operations

Second Quarter Ended Six Months Ended
-------------------- -------------------
June June June June
30, 30, Percent 30, 30, Percent
(millions) 2005 2004 Change 2005 2004 Change
------ ----- ------- ----- ---- -------
Revenue
Income from marketable equity
securities and other
investments (1) $6 $21 (71)% $30 $43 (30)%
Limited partnership investments - 2 (100) 1 6 (83)
Net gain (loss) on disposals
and related expenses (2) - (5) N/A 4 5 (20)
---- ---- ---- ---- ---- -----
Total revenue 6 18 (67) 35 54 (35)
---- ---- ---- ---- ---- -----

Expenses
General expenses 26 15 73 45 39 15
Interest expense 31 35 (11) 65 69 (6)
---- ---- ---- ---- ---- ----
Total expenses 57 50 14 110 108 2
---- ---- ---- ---- ---- ----

Loss before income tax $(51) $(32) N/A % $(75) $(54) N/A %
===== ===== ====== ===== ===== =====

Notes:

Second Quarter Ended Six Months Ended
-------------------- ------------- -----
June June June June
30, 30, Percent 30, 30, Percent
2005 2004 Change 2005 2004 Change
-------------------- ---- ---------------
(1) Includes (millions):
Income (loss) from
Endurance warrants $(1) $- N/A % $15 $4 275 %
Equity earnings - Endurance - 18 (100) - 34 (100)
---- ---- ------ -- -- ---- -------
Total $(1) $18 N/A % $15 $38 (61)%
==== ==== ====== ==== ===== ======

(2) Includes gain on sale of
Endurance stock (millions) $1 $- N/A % $1 $11 (91)%

Investor Contact: Craig Streem
Corporate Vice President, Investor Relations
312-381-3983

Media Contact: Al Orendorff
Director, Public Relations
312-381-3153

59 per share compared to
$192 million or $0. First quarter 2005 results included a pretax gain of
$16 million related to the quarterly revaluation of Endurance warrants
compared to a $4 million gain in the prior year. These forward-looking
statements are subject to certain risks and uncertainties that could cause
actual results to differ materially from either historical or anticipated
results depending on a variety of factors.62 $0.

profitability actuarial

Robinson will continue to have a strong role in business development as well
as the integration of the latest predictive modeling and actuarial tools into
APEX's proprietary underwriting and actuarial models. Although these efforts are not yet
complete, we anticipate adopting restructuring initiatives that will lead us
to record a pretax charge ranging from $200 million to $300 million, beginning
in the third quarter. By comparison, contingent commission
revenue was $43 million in the second quarter of 2004. Brokerage-International and Reinsurance
organic revenues declined 1% and 6%, respectively. Organic
revenue declined 1%, reflecting the loss of contingent commissions and a
decline in outsourcing revenue.9% in 2004.02 of currency hedging
gains.5% 14.2%
Insurance
under-
writing 10.2% 9.
(3) Organic revenue growth excludes the impact of foreign exchange,
acquisitions, divestitures, transfers and items described in (2). We are committed to increasing
profitability by developing growth opportunities and effectively managing
expenses.
Corporate and Other segment revenue was $29 million compared to
$36 million in 2004. There are
47,000 employees working in Aon's 500 offices in more than 120 countries.

This press release contains certain statements related to future results,
or states our intentions, beliefs and expectations or predictions for the
future which are forward -looking statements as that term is defined in the
Private Securities Litigation Reform Act of 1995 .

forensics niis

S.4 billion, with organic revenue declining 2%. Organic revenue growth in consulting services was 2%, while outsourcing
revenues declined 7%, primarily reflecting lost business.

Financial Condition
Total debt and preferred stock decreased $206 million to $1. The supplemental organic revenue growth
information does not affect net income or any other GAAP reported amounts.

Aon Corporation
Segments -- Second Quarter Continuing Operations

Second Quarter Ended
--------------------------------------- ------------------------

Organic
Revenue
Growth
Less: exclu-
Acquis- ding
itions, Less: Organic Contin-
June 30, Less: Divest- All Revenue gent
June 30, 2004 Percent Currency itures+ Other Growth Commis-
(millions) 2005 (1) Change Impact Transfers (2) (3) sions
------- ----- ---- --- ------- -------- ----- ------ -------
Revenue
Risk and
insurance
brokerage
services
Risk
management
and insurance
brokerage -
Americas $601 $597 1% 1% -% 2% (2)% 3%
Risk
management
and insurance
brokerage -
International 592 574 3 4 1 (1) (1) -

Reinsurance
brokerage and
related
services 203 204 - 2 - 4 (6) (6)
Claims services - 57 (100) - (100) - - -
---- ---- ----- --- ----- --- --- ---
Total risk
and insurance
brokerage
services 1,396 1,432 (3) 3 (4) - (2) 1
----- ----- ---- --- ----- --- --- ---
Consulting
Consulting
services 244 230 6 2 3 (1) 2 6
Outsourcing 71 75 (5) 1 - 1 (7) (7)
----- ----- ---- ---- ----- --- --- ---
Total
consulting 315 305 3 2 2 - (1) 3
Insurance
underwriting
Accident +
health and
life 450 441 2 2 - (3) 3 3
Warranty ,
credit and
property +
casualty 366 364 1 2 - 7 (8) (8)
----- ----- ---- ---- ---- --- --- ---
Total
insurance
under-
writing 816 805 1 2 - 1 (2) (2)
----- ----- ---- ---- ---- --- --- ---

Corporate
and other 6 18 (67) N/A N/A N/A N/A N/A

Intersegment
revenues (15) (16) N/A N/A N/A N/A N/A N/A
------- ------ ----- ----- ----- ---- --- - ----
Total $2,518 $2,544 (1)% 2% (2)% 1% (2)% -%
======= ====== ===== ===== ===== ==== ==== ====
Investment
income
(included
in Revenue
above)
Risk and
insurance
brokerage
services $30 $18 67%

Consulting 1 1 -
Insurance
underwriting 39 32 22
Corporate
and other 6 18 (67)
--- --- ----
Total $76 $69 10%
=== === ====
Income (loss)
from
continuing
operations
before
provision
for income
tax

Risk and
insurance
brokerage
services $231 $213 8%

Consulting 29 28 4
Insurance
under-
writing 83 73 14
Corporate
and other (51) (32) N/A
----- ----- -----
Total $292 $282 4%
===== ===== =====

Income from
continuing
operations
before
provision
for income
tax -
margins
Risk and
insurance
brokerage
services 16.8% 8. CHICAGO, Aon Corporation (NYSE: AOC) today
reported first quarter 2005 net income of $200 million or $0. Excluding the impact of contingent commissions, Brokerage -
Americas organic revenue declined 5%. Total debt and preferred stock as a
percentage of total capital was reduced to 29% from 31% over the same period.07) N/A
------- ------- -------
Net income $0.5% 11. 31, Mar.

broking siver

Second Quarter and Six Months Segment Review
Risk and Insurance Brokerage Services second quarter revenue declined 3%
to $1.K. Strong growth in the sales of a
supplemental health product was partially offset by planned reductions in
certain programs and the run-off of non-core businesses.02) N/A (0.2 - %
====== ====== ===== ====== ====== =====

(1) Certain amounts relating to discontinued operations have been
reclassified to conform to the 2005 presentation.
In addition, the net income used in the calculation includes after-
tax interest expense of approximately $2 million for the second
quarters and $3 million for the six months ended June 30, 2005 and
2004.1%
Total 11.02 related to foreign currency translation gains.6%
Consulting 8.

reinsurance verifies

58 per share
from $180 million or $0.12 4 %
Discontinued
operations (0.1 - % 337.8 336.9%
Consulting 9.
First quarter 2005 pretax income and margin comparisons were favorably
influenced by a 5% reduction in expenses largely reflecting the exit of the
claims services business, changes to incentive compensation programs , and
continued emphasis on cost control, in particular, reductions in staff.
Insurance Underwriting revenue increased 1% to $789 million, with segment
organic revenue declining 3% during the quarter . First quarter 2004 results
included an $11 million pretax gain on the sale of Endurance common stock and
Endurance equity earnings of $16 million.

Financial Condition
Total debt and preferred stock increased $76 million to $2. Industry peers provide similar supplemental
information regarding their revenue performance, although they do not make
identical adjustments.