SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 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): April 20, 2001
                                                          --------------

                                 Aon Corporation
                                 ---------------
             (Exact Name of Registrant as Specified in Its Charter)



         Delaware                         1-7933                  36-3051915
         --------                         ------                  ----------
(State or Other Jurisdiction      (Commission File Number)      (IRS Employer
     of Incorporation)                                       Identification No.)


123 N. Wacker Drive, Chicago, Illinois                                 60606
- --------------------------------------                                 -----
(Address of Principal Executive Offices)                             (Zip Code)


Registrant's telephone number, including area code: (312) 701-3000
                                                    --------------



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




ITEM 5.   OTHER EVENTS.

          On April 20, 2001,  Aon  Corporation  (the  "Company")  issued a press
release announcing that the Company's board of directors approved, in principle,
a plan to spin  off its  underwriting  businesses  to its  common  stockholders,
creating two independent, publicly traded companies. The spin-off would take the
form of a tax-free stock dividend to the Company's common stockholders,  pending
a favorable  Internal  Revenue Service ("IRS") ruling.  The transaction requires
final  board  approval,  subject to the  favorable  IRS  ruling,  and  insurance
regulatory approvals.

          The  Company  also  announced  estimated  first  quarter  results  and
reported that its previously  announced business  transformation plan remains on
target to achieve the financial goals it outlined in November 2000. In addition,
the  Company  announced  that its  board of  directors  voted  to  increase  the
quarterly  cash  dividend  to $0.225  per share of common  stock  from $0.22 per
share.

          A copy of the press release is being filed as an exhibit hereto.

ITEM 7.   FINANCIAL STATEMENTS, PRO FORMA FINANCIAL INFORMATION AND EXHIBITS.

(a) - (b) Not applicable.

(c)       Exhibits:

Exhibit
Number    Description of Exhibit
- ------    ----------------------

99        Press release issued by the Company on April 20, 2001.



                                    SIGNATURE

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


                                        AON CORPORATION


Date:  April 24, 2001                   By:    /s/ Harvey N. Medvin
                                               ---------------------
                                        Name:  Harvey N. Medvin
                                        Title: Executive Vice President and
                                               Chief Financial Officer



                                  EXHIBIT INDEX

          The following is a list of the exhibits filed herewith.

Exhibit
Number    Description of Exhibit

99        Press release issued by the Company on April 20, 2001.


                                                                      Exhibit 99

         AON PLANS SPIN-OFF OF UNDERWRITING OPERATIONS TO STOCKHOLDERS;
                        BUSINESS TRANSFORMATION ON TRACK;
          QUARTERLY CASH DIVIDEND INCREASED FOR 50TH CONSECUTIVE YEAR;
              SOLID PERFORMANCE FROM AGGREGATE OPERATING SEGMENTS;
          CORPORATE SEGMENT REVENUE DOWN DUE TO EQUITY MARKET DECLINES

CHICAGO,  April 20, 2001 - Aon Corporation  (NYSE:AOC)  announced today that its
Board  of  Directors  has  approved,  in  principle,  a  plan  to  spin-off  its
underwriting  businesses to its common  stockholders,  creating two independent,
publicly traded companies.  The spin-off would take the form of a tax-free stock
dividend to Aon's  common  stockholders,  pending a favorable  Internal  Revenue
Service (IRS) ruling. The transaction requires final Board approval,  subject to
the favorable IRS ruling, and certain insurance regulatory approvals.

Aon also reported that the business  transformation plan previously announced in
November 2000 is on track and operating  segment  pretax income in the aggregate
increased  by  approximately  7  percent  before  special  charges  in the first
quarter. "Our combined operating segments posted solid results for the quarter,"
Aon Chairman and Chief Executive  Officer  Patrick G. Ryan said.  "Equity market
volatility  negatively  impacted our  non-operating  corporate  segment revenue,
however, due primarily to limited partnership valuation declines."

Corporate   segment  revenue,   derived   primarily  from  limited   partnership
investments,  declined  to  approximately  negative  $85  million  for the first
quarter  versus a positive  $30  million in the first  quarter  last year.  This
represents a $115 million unfavorable  year-over-year  comparison equaling $0.26
per share.

The Company also  announced  that the quarterly cash dividend has been increased
to $0.225 marking the 50th consecutive year of increases.

SPIN-OFF OF UNDERWRITING OPERATIONS

"The spin-off of our  underwriting  businesses is the next logical step in Aon's
evolution as a client-centric  company," Ryan said.  "Through Aon's  leadership,
the major  consolidation phase of the global insurance brokerage industry is now
complete. The successful  implementation of our business  transformation program
will result in greater efficiency, enhanced productivity and better service. Now
we will seek to accelerate  the growth of our key businesses by allowing each to
focus directly on its core client base. Once separate, each of the two companies
will be better able to pursue new business opportunities unhindered by potential
conflicts resulting from being under one holding company."

Patrick G. Ryan will remain  chairman and CEO of Aon  Corporation and Michael D.
O'Halleran  will  continue as president  and chief  operating  officer.  Richard
Ravin, who is currently  chairman of Aon's Combined Insurance Company of America
subsidiary,  will be  president  and CEO of the new holding  company to be named
Combined  Specialty  Corporation.  David Cole,  now  president  and CEO of Aon's
Virginia  Surety  Company,  will be  vice  chairman  and  COO.  He will  also be
chairman,  president  and CEO of the new holding  company's  specialty  casualty



subsidiary,  to be  named  Combined  Specialty  P&C.  Ryan  will  also  serve as
non-executive chairman of Combined Specialty Corporation.

"Richard and David are proven  leaders of specialty  underwriting  companies and
collectively  bring over 60 years of  insurance  experience  to the new company,
along with a vision for building a world-class organization," Ryan said.

Aon's underwriting businesses currently operate through five major subsidiaries:
Combined  Insurance  Company of America,  Combined Life Insurance Company of New
York,  Virginia Surety Company,  Inc., London General Insurance Company Limited,
and Aon Warranty Group,  Inc. These  subsidiaries now carry and will continue to
carry virtually all of Aon's fixed maturity investments (95 percent of which are
investment   grade)  and  equity   security   investments   (including   limited
partnerships) on their balance sheets.  These  subsidiaries  will be part of the
new  Combined  Specialty  Corporation.  Combined  Specialty  would have  minimal
goodwill  but  would be  allocated  a  portion  of Aon's  interest  expense  and
corporate  general expenses.  Combined  Specialty's total assets are expected to
exceed $7  billion.  Post  spin-off,  Aon  would  have an  investment  portfolio
comprised  predominantly  of  short-term  investment  securities  related to its
brokerage  and  consulting  operations.  Aon would retain  virtually  all of its
accounting goodwill. Although the Company has not yet finalized decisions on the
capital structures of the post spin-off companies, the intention is to establish
capital structures for each company necessary to maintain current ratings.

Combined  Specialty  is  expected to focus on its core  accident  and health and
warranty  lines and to  gradually  reintroduce  specialty  property and casualty
products.  Aon had  previously  issued  policies in the  specialty  property and
casualty  lines through 1996 when the Company took a decisive  strategic step to
sell its life insurance  companies  (Union  Fidelity Life Insurance Co. and Life
Insurance  Co. of Virginia) and to expand its  brokerage  business.  These steps
necessitated  putting the specialty  property and casualty business into run-off
to avoid any conflicts  with the  expanding  brokerage  operations.  Since 1996,
Aon's  underwriting  subsidiaries  have  focused  almost  solely on accident and
health and warranty  business.  Creating a separate company through the spin-off
of Aon's underwriting operations would allow Combined Specialty to seek business
through  additional  brokerage  distribution  channels  beyond  Aon.  Additional
opportunities  also exist to grow niche  affinity  and  international  business.
Combined  Specialty  will be able to  market  specialty  property  and  casualty
policies  that would  otherwise be in conflict  with Aon's  insurance  brokerage
operations.

Aon's  underwriting  subsidiaries  have a solid record of strong balance sheets,
consistent  profitability  and cash flow. After the spin-off,  each underwriting
subsidiary is expected to maintain its strong  independent claims paying ratings
for the protection of its policyholders.

"The need to fund the growth of  brokerage  and  consulting  operations  through
internally  generated  cash  flow  from our  underwriting  segment  has  greatly
diminished.  Now, new opportunities that are achieved by focusing as independent
companies with unique client bases, selling strategies and products and services
have become more compelling," Ryan said.

Underwriting  primarily  serves  individual  consumers,  automobile  dealers and
retailers,  with a network of professional  career agents who sell insurance and
warranty protection.  Insurance



brokerage  and  consulting   professionals   provide  advice,   fulfillment  and
outsourcing  solutions in the complex areas of risk management and human capital
management that concentrate on large-to-medium-sized companies.

The spin-off is expected to be finalized by the end of 2001.  At the time of the
spin-off, Aon stockholders will initially have the same proportionate  ownership
in the two  independent  companies  represented by shares of Aon Corporation and
the new Combined Specialty Corporation.

"Our industry-leading brokerage and consulting businesses have the scale to grow
independently while our underwriting  business can use its internally  generated
cash flow to invest  in new  specialty  casualty  products  where it has  proven
expertise," Ryan said.  "Spinning off our  underwriting  operation will minimize
the potential for conflict with our  brokerage  and  consulting  clients.  Under
independent  leadership,  the new holding company can expand specialty  casualty
underwriting  and seek new  business  through  brokerage  distribution  channels
around  the  world.  The  separation  also has the  added  benefit  of  aligning
employees'   long-term  incentive   compensation  with  the  valuation  of  each
respective company," he added.

BUSINESS TRANSFORMATION PLAN

Aon also said today that its business  transformation  plan remains on target to
achieve  the  financial  goals it  outlined  in  November  2000.  As  previously
announced, annual savings from the plan are projected to be between $150 million
to $200  million.  The  majority  of the  annualized  savings  will  begin to be
realized  starting in fourth  quarter  2001.  Total pretax costs  related to the
business  transformation  were  estimated  to be between  $250  million and $325
million.  The majority of these costs will be recorded as a special  charge over
three  consecutive  quarters  that  began  with the  fourth  quarter  2000 which
included  an $82  million  pretax  charge.  For  first  quarter  2001,  business
transformation  related  charges are estimated to be  approximately  $70 million
pretax.

In U.S.  retail  brokerage,  the  conversion  from a geographic  model to a more
client-focused  organizational  structure is well underway.  Decisions have been
made on the location of the four major U.S. retail brokerage  processing centers
- - New York City, Los Angeles, Houston and Glenview, Illinois - and the migration
process  for  certain  client  service  functions  to  these  centers  has  been
initiated.  The policy  management and accounting  system that is the foundation
for much of the  transformation has been fully populated with client information
and has been further  upgraded to provide even  greater  functionality.  Central
U.S.  processing  locations  have also been  identified  and announced for other
groups: affinity,  wholesale,  managing underwriting,  claims services,  premium
accounting, and broad market personal lines.

The  Company  has  initiated  the  rollout  process  of its  proprietary  policy
management  and  accounting  system  applications  from the U.S. to the U.K. and
Canada. Significant steps have also been taken to begin to better leverage Aon's
e-commerce and technology platforms. Aon will have a common global platform with
local applications.

"We are on  target to  achieve  the  benefits  of our  business  transformation:
expanded  growth as well as cost savings from  improved  technologies,  business
processes and  organizational



structures,"  Ryan said.  "We believe more benefits for both our clients and our
stockholders  will be achieved as we continue to  implement  the  transformation
plan."

FIRST QUARTER OUTLOOK

Aon also said today that  total  pretax  income  from its  operating  segments -
insurance  brokerage,  consulting  and  underwriting - are estimated to increase
approximately  7 percent from $266 million in first quarter 2000 before  special
charges.   "Organic  revenue  growth  for  brokerage  and  consulting  increased
approximately  8 percent for the  quarter,"  Ryan  stated.  During the  quarter,
premium rates  continued to rise across all major  property and casualty  lines.
Consulting  had  continued  strong  results and the  underwriting  segment  that
includes  warranty is expected  to perform in line with the first  quarter  last
year.  Warranty  incurred  higher  losses  than  expected  in the quarter due to
unusual  claims  activity for an isolated  program that has been  terminated and
will not impact future quarters.

The  non-operating   corporate  segment  has  experienced  significant  non-cash
valuation  declines in the equity portfolio  related primarily to investments in
limited partnerships accounted for on the equity method. First quarter corporate
segment revenue,  the majority of which is comprised of revenue from our limited
partnership  portfolio,  is estimated to be negative $85 million compared with a
positive $30 million in first  quarter  2000 - a  difference  of $115 million or
$0.26 per share. This decline is largely due to valuation changes. The long-term
history of Aon's limited partnership  investments is that they have outperformed
other investments.  These investments are well diversified by industry type, and
the majority of these investments are in buyout equity partnerships.  Aon's full
first quarter earnings will be released on May 3, 2001.

FULL YEAR 2001 OUTLOOK

"We  continue to believe  that Aon's  combined  operating  segments - brokerage,
consulting and underwriting - will achieve  double-digit pretax income growth in
2001," Ryan said. "However, given the decline of the equity markets, Aon may not
be able to achieve  double-digit  consolidated  earnings per share growth before
special charges in 2001 compared with 2000."

DIVIDEND INCREASE ANNOUNCED

Aon said today its Board of  Directors  voted to  increase  its  quarterly  cash
dividend to $0.225 per common share from $0.22.  This marks the 50th consecutive
year in which Aon has increased its quarterly cash  dividend.  The cash dividend
will be  payable  on May 16,  2001 to  stockholders  of  record  at the close of
business on May 3, 2001.

While  the  respective  Boards of each  company  will  determine  their own cash
dividend  policy  post-spinoff,  at this time it is  expected  that the  initial
combined  cash  dividends  of the two  companies  would be at the level of Aon's
current cash dividend.

ANNUAL MEETING AND INVESTMENT ANALYST WEBCAST - 10:00 AM (CDT)
                                                --------------

Aon Corporation  Chairman and CEO Patrick G. Ryan will host the Company's annual
stockholders'  meeting  today,  April 20, 2001, at 10:00 AM (CDT) and will cover
all of the topics in this press  release.  The  presentation  and  questions  by
stockholders  attending  the  meeting in



Chicago  can be  listened  to via a live  webcast  by going to Aon's  website at
www.aon.com. This webcast will be in listen only mode. A Windows Media Player is
- -----------
required to listen to this webcast.

POST MEETING INVESTMENT ANALYST Q&A WEBCAST - 1:30 PM (CDT)
                                              -------------
At 1:30 PM  (CDT),  following  the  stockholders'  meeting,  Mr.  Ryan and other
members of Aon's senior  management team will host a webcast to answer questions
from  institutional   investors  and  financial  analysts.   We  recommend  that
                                                             -------------------
investment  analysts  and  investors  listen  to the 10 a.m.  webcast  since the
- --------------------------------------------------------------------------------
presentation addressing this press release will not be repeated at 1:30 p.m. All
- ----------------------------------------------------------------------------
investors  and other  interested  parties are also  invited to listen.  Both the
annual meeting and the question and answer session webcasts will be archived for
two weeks. In the U.S. and Canada, the annual meeting is available for replay at
800-839-4225  and the question and answer session is available at  888-568-0542.
Outside the U.S. and Canada,  the number for the annual meeting is  402-998-1204
and the question and answer session replay can be heard at 402-998-1512.

Aon Corporation (www.aon.com) is a holding company that is comprised of a family
                 -----------
of insurance  brokerage,  consulting  and insurance  underwriting  subsidiaries.
Aon's  common  stock is listed on the New York,  Chicago,  Frankfurt  and London
stock exchanges.

This press release may contain  certain  statements  relating to future results,
which are  forward-looking  statements  as that term is defined  in the  Private
Securities Litigation Reform Act of 1995. These  forward-looking  statements are
subject to certain risks and  uncertainties  that could cause actual  results to
differ materially from historical results or those  anticipated,  depending on a
variety of factors such as general  economic  conditions in different  countries
around the  world,  fluctuations  in global  equity  and fixed  income  markets,
changes in  commercial  property and casualty  premium  rates,  the  competitive
environment,  the actual cost of resolution of contingent liabilities, the final
form of the business  transformation  plan,  the ultimate cost and timing of the
implementation  thereof,  the actual cost savings and other  benefits  resulting
therefrom,  whether the Company  ultimately  implements the proposed spin-off of
its  underwriting  operations,  and the timing and terms  associated  therewith.
Further information  concerning the Company and its business,  including factors
that potentially  could materially  affect the Company's  financial  results are
contained in the Company's filings with the Securities and Exchange Commission.


                                       ###



Contacts: Sean O'Neill
          Vice President Financial Relations
          312-701-3983

          Robert Rosholt
          Executive Vice President - Media
          312-701-3092