SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM 10-Q

       X         QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d)
       -           OF THE SECURITIES AND EXCHANGE ACT OF 1934

                  FOR THE QUARTERLY PERIOD ENDED MARCH 31, 2001

                                       OR

       _        TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d)
                     OF THE SECURITIES EXCHANGE ACT OF 1934

                          Commission file number 1-7933

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

           DELAWARE                                            36-3051915
           --------                                            ----------
(State or Other Jurisdiction of                             (IRS Employer
 Incorporation or Organization)                              Identification No.)



123 N. WACKER DR, CHICAGO, ILLINOIS                               60606
- -----------------------------------                               -----
(Address of Principal Executive Offices)                       (Zip Code)

             (312) 701-3000
              -------------
     (Registrant's Telephone Number)


Indicate  by check  mark  whether  the  Registrant:  (1) has filed  all  reports
required to be filed by Section 13 or 15(d) of the  Securities  and Exchange Act
of 1934  during the  preceding  3 months (or for such  shorter  period  that the
Registrant was required to file such reports),  and (2) has been subject to such
filing requirements for the past 90 days.   YES  X  NO
                                                ---    ---


Number of shares of common stock outstanding:

                                                           No. Outstanding
               Class                                         as of 3-31-01
               -----                                         -------------

        $1.00 par value Common                                261,860,632





                                             PART 1
                                      FINANCIAL INFORMATION
                                         Aon CORPORATION
                    Condensed Consolidated Statements of Financial Position


 (millions)                                                      AS OF            AS OF
                                                             MARCH 31, 2001   DEC. 31, 2000
                                                            --------------------------------
 ASSETS                                                       (Unaudited)

 INVESTMENTS

                                                                             
   Fixed maturities at fair value                               $    2,342       $    2,337

   Equity securities at fair value                                     542              492

   Short-term investments                                            2,420            2,325

   Other investments                                                   775              865

                                                            ---------------  ---------------
       TOTAL INVESTMENTS                                             6,079            6,019


 CASH                                                                  886            1,118


 RECEIVABLES

   Insurance brokerage and consulting
        services                                                     6,887            6,952

   Premiums and other                                                1,163            1,278

                                                            ---------------  ---------------
       TOTAL RECEIVABLES                                             8,050            8,230


 EXCESS OF COST OVER NET ASSETS PURCHASED                            3,380            3,427


 OTHER INTANGIBLE ASSETS                                               485              489


 OTHER ASSETS                                                        3,157            2,968



                                                            ---------------  ---------------
       TOTAL ASSETS                                             $   22,037       $   22,251
                                                            ===============  ===============



                                                                 AS OF            AS OF
                                                             MARCH 31, 2001   DEC. 31, 2000
                                                            --------------------------------
 LIABILITIES AND STOCKHOLDERS' EQUITY                         (Unaudited)

 INSURANCE PREMIUMS PAYABLE                                     $    8,432       $    8,212

 POLICY LIABILITIES
   Future policy benefits                                            1,054            1,054
   Policy and contract claims                                          856              801
   Unearned and advance premiums                                     1,960            1,935
   Other policyholder funds                                            953            1,069
                                                            ---------------  ---------------
       TOTAL POLICY LIABILITIES                                      4,823            4,859

 GENERAL LIABILITIES
   General expenses                                                  1,676            1,619
   Short-term borrowings                                                60              309
   Notes payable                                                     1,804            1,798
   Other liabilities                                                 1,029            1,216
                                                            ---------------  ---------------
       TOTAL LIABILITIES                                            17,824           18,013


 COMMITMENTS AND CONTINGENT LIABILITIES

 REDEEMABLE PREFERRED STOCK                                             50               50

 COMPANY-OBLIGATED MANDATORILY REDEEMABLE
   PREFERRED CAPITAL SECURITIES OF SUBSIDIARY
   TRUST HOLDING SOLELY THE COMPANY'S JUNIOR
   SUBORDINATED DEBENTURES                                             800              800


 STOCKHOLDERS' EQUITY
   Common stock - $1 par value                                         264              264
   Paid-in additional capital                                          715              706
   Accumulated other comprehensive loss                               (413)            (377)
   Retained earnings                                                 3,087            3,127
   Less - Treasury stock at cost                                       (81)            (118)
          Deferred compensation                                       (209)            (214)
                                                            ---------------  ---------------
       TOTAL STOCKHOLDERS' EQUITY                                    3,363            3,388

                                                            ---------------  ---------------
       TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY               $   22,037       $   22,251
                                                            ===============  ===============



See the accompanying notes to the condensed consolidated financial statements.

                                     - 2 -



                                             Aon CORPORATION
                               Condensed Consolidated Statements of Income
                                                (Unaudited)

                                                                                                          FIRST QUARTER ENDED
                                                                                                   --------------------------------
(millions except per share data)                                                                    MARCH 31, 2001   MARCH 31, 2000
                                                                                                   ---------------  ---------------

                                                                                                                       
 REVENUE
    Brokerage commissions and fees ...........................................................            $ 1,281          $ 1,205
    Premiums and other .......................................................................                508              468
    Investment income ........................................................................                 22              137
                                                                                                   ---------------  ---------------
       TOTAL REVENUE .........................................................................              1,811            1,810
                                                                                                   ---------------  ---------------

 EXPENSES
    General expenses . .......................................................................              1,396            1,271
    Benefits to policyholders ................................................................                292              252
    Interest expense .........................................................................                 36               31
    Amortization of intangible assets ........................................................                 39               38
                                                                                                   ---------------  ---------------
       TOTAL EXPENSES. .......................................................................              1,763            1,592
                                                                                                   ---------------  ---------------

 INCOME BEFORE INCOME TAX, MINORITY INTEREST AND ACCOUNTING CHANGE ...........................                 48              218
    Provision for income tax . ...............................................................                 19               85
                                                                                                   ---------------  ---------------
 INCOME BEFORE MINORITY INTEREST AND ACCOUNTING CHANGE .......................................                 29              133
    Minority interest - 8.205% trust preferred capital securities ............................                (10)             (10)
                                                                                                   ---------------  ---------------
 INCOME BEFORE ACCOUNTING CHANGE .............................................................                 19              123
    Cumulative effect of change in accounting principle, net of tax ..........................                  -               (7)
                                                                                                   ---------------  ---------------
 NET INCOME ..................................................................................            $    19          $   116
                                                                                                   ===============  ===============
    Preferred stock dividends ................................................................                 (1)              (1)
                                                                                                   ---------------  ---------------
 NET INCOME AVAILABLE FOR COMMON STOCKHOLDERS ................................................            $    18          $   115
                                                                                                   ===============  ===============

 BASIC NET INCOME PER SHARE:
    Before accounting change .................................................................            $  0.07          $  0.47
    Cumulative effect of change in accounting principle ......................................                  -            (0.03)
                                                                                                   ---------------  ---------------
                Basic net income per share ...................................................            $  0.07          $  0.44
                                                                                                   ===============  ===============

 DILUTIVE NET INCOME PER SHARE:
    Before accounting change .................................................................            $  0.07          $  0.47
    Cumulative effect of change in accounting principle ......................................                  -            (0.03)
                                                                                                   ---------------  ---------------
                Dilutive net income per share ................................................            $  0.07          $  0.44
                                                                                                   ===============  ===============

 CASH DIVIDENDS PER SHARE PAID ON COMMON STOCK ...............................................            $  0.22          $  0.21
                                                                                                   ===============  ===============

 Dilutive average common and common equivalent shares outstanding ............................              267.9            260.5
                                                                                                   ===============  ===============


See the accompanying notes to the condensed consolidated financial statements.

                                     - 3 -



                                             Aon CORPORATION
                             Condensed Consolidated Statements of Cash Flows
                                               (Unaudited)

                                                                                                 FIRST QUARTER ENDED
                                                                                          --------------------------------
                                                                                              MARCH 31,        MARCH 31,
 (millions)                                                                                     2001             2000
                                                                                          --------------    --------------
                                                                                                                
 CASH FLOWS FROM OPERATING ACTIVITIES:
   Net income ..........................................................................        $    19           $   116
   Adjustments to reconcile net income to cash provided by operating activities
        Cumulative effect of change in accounting principle, net of tax ................              -                 7
        Insurance operating assets and liabilities net of reinsurance ..................             48                87
        Amortization of intangible assets ..............................................             39                38
        Depreciation and amortization of property, equipment and software ..............             44                44
        Income taxes ...................................................................            (20)               17
        Special charges and purchase accounting liabilities ............................             23               (43)
        Valuation changes on investments, income on disposals and impairments ..........             76               (25)
        Other receivables and liabilities - net ........................................            103               (95)
                                                                                          --------------    --------------
           CASH PROVIDED BY OPERATING ACTIVITIES .......................................            332               146
                                                                                          --------------    --------------

 CASH FLOWS FROM INVESTING ACTIVITIES:
   Sale of investments
        Fixed maturities
           Maturities ..................................................................             30                28
           Calls and prepayments .......................................................             16                32
           Sales .......................................................................            365                57
        Equity securities ..............................................................            162                25
        Other investments ..............................................................            135                57
   Purchase of investments
        Fixed maturities ...............................................................           (385)             (130)
        Equity securities ..............................................................           (196)              (15)
        Other investments ..............................................................            (32)             (128)
   Sale (purchase) of short-term investments - net .....................................           (180)              100
   Acquisition of subsidiaries .........................................................            (44)              (35)
   Property and equipment and other - net ..............................................            (57)              (59)
                                                                                          --------------    --------------
           CASH USED BY INVESTING ACTIVITIES ...........................................           (186)              (68)
                                                                                          --------------    --------------

 CASH FLOWS FROM FINANCING ACTIVITIES:
    Treasury stock transactions - net ..................................................             18               (23)
    Issuance (payments) of short-term borrowings - net .................................           (252)               41
    Issuance of long-term debt .........................................................             15                 -
    Repayment of long-term debt ........................................................              -               (16)
    Interest sensitive, annuity and investment-type contracts
        Deposits .......................................................................              3                34
        Withdrawals ....................................................................           (102)             (123)
    Cash dividends to stockholders .....................................................            (58)              (54)
                                                                                          --------------    --------------
           CASH USED IN FINANCING ACTIVITIES ...........................................           (376)             (141)
                                                                                          --------------    --------------

 EFFECT OF EXCHANGE RATE CHANGES ON CASH ...............................................             (2)                -
                                                                                          --------------    --------------
 DECREASE IN CASH ......................................................................           (232)              (63)
 CASH AT BEGINNING OF PERIOD ...........................................................          1,118               837
                                                                                          --------------    --------------
 CASH AT END OF PERIOD .................................................................        $   886           $   774
                                                                                          ==============    ==============


See the accompanying notes to condensed consolidated financial statements.

                                     - 4 -


NOTES TO THE CONDENSED CONSOLIDATED FINANCIAL STATEMENTS


1.       Statement of Accounting Principles
         ----------------------------------

         The financial  results included in this report are stated in conformity
         with accounting  principles generally accepted in the United States and
         are unaudited but include all normal  recurring  adjustments  which the
         Registrant  ("Aon") considers  necessary for a fair presentation of the
         results for such  periods.  These interim  figures are not  necessarily
         indicative of results for a full year as further discussed below.

         Refer to the consolidated  financial statements and notes in the Annual
         Report  to  Stockholders  for the  year  ended  December  31,  2000 for
         additional  details  of  Aon's  financial   position,   as  well  as  a
         description  of the  accounting  policies  which  have  been  continued
         without  material  change.  The details  included in the notes have not
         changed  except as a result of normal  transactions  in the interim and
         the events mentioned in the footnotes below.


2.       Accounting and Disclosure Changes
         ---------------------------------

         In December 1999, the Securities and Exchange  Commission  (SEC) issued
         Staff  Accounting  Bulletin (SAB) No. 101, which provides  guidance for
         applying  generally  accepted  accounting  principles  relating  to the
         timing of revenue  recognition in financial  statements  filed with the
         SEC.  Effective  January 1, 2000, in accordance  with the provisions of
         SAB 101, Aon established a provision for estimated returned commissions
         from policy  cancellations.  In 1999 and previous years, Aon recognized
         returned commissions when they occurred.  The cumulative effect of this
         accounting  change was an  after-tax  charge of $7 million or $0.03 per
         share in the first quarter of 2000.

         Aon has adopted Financial Accounting Standards Board  (FASB)  Statement
         No. 133, Accounting for Derivative Instruments  and Hedging Activities,
         as amended as of October 1, 2000. Reference should be made to footnotes
         1 and 13 in Aon's  Annual  Report as filed with Form 10-K for the  year
         2000 for further information.

         In September  2000,  the Financial  Accounting  Standards  Board issued
         Statement No. 140,  Accounting for Transfers and Servicing of Financial
         Assets and  Extinguishments of Liabilities.  Statement No. 140 replaces
         Statement  No.  125  and  revises  the  standards  for  accounting  for
         securitizations  and other transfers of financial assets and collateral
         and requires  certain  disclosures.  Statement No. 140 is effective for
         all  transfers  of  financial  assets  occurring  after March 31, 2001.
         Implementation  of Statement No. 140 will not have a material impact on
         the consolidated financial statements.



3.       Subsequent Event
         ----------------

         On April 20, 2001, Aon's Board of Directors approved,  in principle,  a
         plan  to  spin-off  its   underwriting   businesses   to  Aon's  common
         stockholders,  creating two independent, publicly traded companies. The
         spin-off would take the form of a tax-free  dividend of common stock of
         the  new  company 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.

                                     - 5 -

4.       Comprehensive Income (Loss)
         ---------------------------

         The components of comprehensive  income (loss), net of related tax, for
         the first quarter ended March 31, 2001 and 2000 are as follows:



                  (millions)                                        2001                 2000
                                                                ------------         ------------
                                                                                  
                  Net income                                      $      19            $    116
                  Net derivative losses                                 (12)                  -
                  Net unrealized investment gains                        19                   3
                  Net foreign exchange losses                           (43)                (32)
                                                                -------------        ------------
                  Comprehensive income (loss)                     $     (17)           $     87
                                                                =============        ============



         The components of accumulated other  comprehensive loss, net of related
         tax, at March 31, 2001 and December 31, 2000, are as follows:



                  (millions)                                         2001                 2000
                                                                -------------        -------------
                                                                                    
                  Net derivative gains (losses)                  $      (6)           $       6
                  Net unrealized investment losses                     (53)                 (72)
                  Net foreign exchange losses                         (310)                (267)
                  Net additional minimum pension liability             (44)                 (44)
                                                                -------------        --------------
                  Accumulated other comprehensive loss           $    (413)           $     (377)
                                                                =============        ==============



5.       Business Segments
         -----------------

         Aon classifies its businesses  into three  operating  segments based on
         the type of service or product, and a fourth nonoperating  segment. The
         Insurance  Brokerage and Other Services segment  consists  primarily of
         Aon's retail and reinsurance  brokerage and related  operations,  which
         include wholesale and claims services.  The Consulting segment is Aon's
         employee  benefit  and  human  capital  consulting  organization.   The
         Insurance  Underwriting  segment is  comprised  of life,  accident  and
         health  coverage  and  extended  warranty  and  property  and  casualty
         insurance  products.  The Corporate and Other segment is non-operating.
         Revenues  consist  primarily  of  valuation  changes for investments in
         limited  partnerships,  income from certain  other  investments  (which
         include  non-income  producing  equities)  and  income  and  losses  on
         disposals  of  all securities,  including  those  pertaining  to assets
         maintained by the  operating  segments.  Corporate  and  Other  general
         expenses  include administrative  and  certain  information  technology
         costs.

         Amounts reported in the tables for the four segments,  when aggregated,
         total  to  the  amounts  in  the  accompanying  condensed  consolidated
         financial statements. Revenues are attributed to geographic areas based
         on the location of the resources  producing the revenues.  There are no
         material inter-segment amounts to be eliminated.

                                     - 6 -

Selected information reflecting Aon's operating segments follows:



- -------------------------------------------------------------------------------------------------------------------------------
First quarter ended March 31:                 Insurance Brokerage                                               Insurance
(millions)                                     and Other Services                  Consulting                  Underwriting
                                           ------------------------------------------------------------------------------------
                                              2001           2000                2001          2000           2001        2000
- -------------------------------------------------------------------------------------------------------------------------------
                                                                                                         
Revenue
   United States                            $    541       $   524            $   135       $    99         $   406    $   376
   United Kingdom                                205           204                 36            39              80         78
   Continent of Europe                           240           226                 22            22              28         26
   Rest of World                                 131           120                 19            16              53         50
- --------------------------------------------------------------------------------------------------------------------------------
Total revenue                               $  1,117       $ 1,074            $   212       $   176         $   567    $   530
- --------------------------------------------------------------------------------------------------------------------------------

Income before income taxes
    excluding special charges               $    196       $   180            $     25      $    19         $    68    $    67
Special charges                                   70             -                   1            -               1          -
- --------------------------------------------------------------------------------------------------------------------------------
Income before income taxes                  $    126       $   180            $     24      $    19         $    67    $    67
- --------------------------------------------------------------------------------------------------------------------------------



Selected information for Aon's non-operating segment follows:



- ----------------------------------------------------------------------------------------------------------------------
Corporate and Other
(millions)                                             First quarter ended March 31          2001               2000
- ----------------------------------------------------------------------------------------------------------------------

                                                                                                            
Corporate and other revenue:
Change in valuation of private limited partnership
   investments                                                                            $   (56)            $   28
Income from marketable equity securities and other
   investments                                                                                  1                  3
                                                                                         -----------------------------
Corporate and other revenue before loss on
   disposals and related expenses                                                             (55)                31
Loss on disposals and related expenses*                                                       (30)                (1)
                                                                                         -----------------------------
Corporate and other revenue                                                               $   (85)            $   30
                                                                                         -----------------------------
Non-operating expenses:
  General expenses                                                                        $    19             $   20
  Interest expense                                                                             36                 31
  Amortization of goodwill                                                                     29                 27
- ----------------------------------------------------------------------------------------------------------------------
Loss before income tax                                                                    $  (169)            $  (48)
- ----------------------------------------------------------------------------------------------------------------------
<FN>
* In 2001, includes impairment write-downs of $29 million.
</FN>


6.       Capital Stock
         -------------

         During first  quarter  2001,  Aon reissued  1,138,000  shares of common
         stock from treasury for employee  benefit  plans and 146,500  shares in
         connection with the employee stock purchase plan. Aon purchased  98,900
         shares of its common stock at a total cost of $3.5 million during first
         quarter  2001.  There were 2.6 million  shares of common  stock held in
         treasury at March 31, 2001.

                                     - 7 -

7.       Capital Securities
         ------------------

         In 1997, Aon Capital A, a subsidiary  trust of Aon, issued $800 million
         of 8.205% mandatorily  redeemable preferred capital securities (capital
         securities).  The sole asset of Aon Capital A is $824 million aggregate
         principal  amount  of  Aon's  8.205%  Junior  Subordinated   Deferrable
         Interest Debentures due January 1, 2027.


8.       Business Combinations
         ---------------------

         In first  quarter  2001,  Aon made  total  payments  of $4  million  on
         restructuring  charges and purchase accounting  liabilities relating to
         business combinations.

         The following table  demonstrates the activity related to the liability
         for termination  benefits and abandoned  leases recorded as expenses in
         1999:




                                                         Termination                 Lease
         (millions)                                        Benefits                Abandonments             Total
         ----------------------------------------------------------------------------------------------------------
                                                                                                 
         Initial liability                               $      67                $    11                 $    78
         Cash payments in 1999                                 (51)                    (6)                    (57)
         Cash payments in 2000                                  (9)                     -                      (9)
         Credit to expense in 2000                               -                     (4)                     (4)
         Cash payments in 2001                                  (1)                     -                      (1)
         Foreign currency revaluation                            -                     (1)                     (1)
         ----------------------------------------------------------------------------------------------------------
         Balance at March 31, 2001                       $       6                $     -                 $     6
         ----------------------------------------------------------------------------------------------------------


         The  following  table   demonstrates   the  activity   related  to  the
         liabilities established as a result of 1998 acquisitions:




                                                         Termination                 Lease
         (millions)                                        Benefits                Abandonments             Total
         ----------------------------------------------------------------------------------------------------------
                                                                                                 
         Initial liability                               $      40                $     30                $    70
         Cash payments in 1998                                 (16)                     (4)                   (20)
         Cash payments in 1999                                 (24)                     (6)                   (30)
         Cash payments in 2000                                   -                     (14)                   (14)
         Foreign currency revaluation                            -                      (2)                    (2)
         ----------------------------------------------------------------------------------------------------------
         Balance at March 31, 2001                       $       -                $      4                $     4
         ----------------------------------------------------------------------------------------------------------



                                     - 8 -

         The following table  demonstrates  the activity related to the Aon Plan
         liabilities recorded as expenses in 1996 and 1997:



                                                                                       Lease
                                                                                    Abandonments
                                                            Termination               and Other
        (millions)                                            Benefits               Exit Costs             Total
        -----------------------------------------------------------------------------------------------------------
                                                                                                    
        Balance at  December 31, 1996                           $ 12                    $ 48                 $ 60
        Expense charged in 1997                                   40                      68                  108
        Cash payments in 1997 and 1998                           (52)                    (36)                 (88)
        Cash payments in 1999                                      -                     (24)                 (24)
        Credit to expense in 1999                                  -                     (11)                 (11)
        Cash payments in 2000                                      -                     (11)                 (11)
        Cash payments in 2001                                      -                      (1)                  (1)
        Foreign currency revaluation                               -                      (3)                  (3)
        -----------------------------------------------------------------------------------------------------------
        Balance at March 31, 2001                               $  -                    $ 30                 $ 30
        -----------------------------------------------------------------------------------------------------------



         The following table  demonstrates  the activity  related to the A&A and
         Bain Hogg  plan  liabilities  established  as a result of 1996 and 1997
         acquisitions:


                                                                                       Lease
                                                                                    Abandonments
                                                            Termination               and Other
        (millions)                                            Benefits               Exit Costs             Total
        -----------------------------------------------------------------------------------------------------------
                                                                                                    
         Initial liability                                      $ 100                   $ 164               $ 264
         Cash payments in 1997 and 1998                          (100)                    (89)               (189)
         Cash payments in 1999                                      -                     (28)                (28)
         Charge to expense in 1999                                  -                      13                  13
         Charge to expense in 2000                                  -                       4                   4
         Cash payments in 2000                                      -                     (14)                (14)
         Cash payments in 2001                                      -                      (2)                 (2)
         Foreign currency revaluation                               -                      (5)                 (5)
         ----------------------------------------------------------------------------------------------------------
         Balance at March 31, 2001                              $   -                   $  43               $  43
         ----------------------------------------------------------------------------------------------------------


All of Aon's  unpaid  liabilities  relating to  acquisitions  are  reflected  in
general  expense  liabilities  in  the  condensed  consolidated   statements  of
financial position.


9.       Business Transformation Plan
         ----------------------------

         In fourth  quarter  2000,  Aon  commenced a plan of  restructuring  its
         worldwide    operations.    This   plan   constitutes   the   "business
         transformation  plan" to be  implemented  during the fourth  quarter of
         2000 and  throughout  2001. A pretax  special charge of $82 million was
         recorded in fourth  quarter  2000 and $72  million was  recorded in the
         first  quarter  2001,  which are  included  in general  expenses in the
         condensed  consolidated  statement  of income.  The charge in the first
         quarter 2001  included  costs  related to  termination  benefits of $23
         million,  other costs to exit an  activity  of  $3  million  and  asset
         impairments and other charges of $46 million.  Since  the beginning  of
         the plan, approximately  2,000  employees have been notified that their
         positions have been or will be eliminated,  the majority of which  were
         related to the Insurance  Brokerage and  Other Services  segment in the
         U.S. and the U.K.

                                     - 9 -



         In the first  quarter  2001,  Aon made total  payments  of $22  million
         related to the business transformation plan.

         The following  demonstrates  the activity  related to the liability for
         termination benefits and costs to exit an activity.


                                                                                Other Costs
                                                         Termination            to Exit an
           (millions)                                      Benefits              Activity                Total
           -----------------------------------------------------------------------------------------------------
                                                                                                 
           Expense charged in 2000                           $ 54                 $  6                   $  60
           Cash payments in 2000                              (13)                  (3)                    (16)
           Expense charged in 2001                             23                    3                      26
           Cash payments in 2001                              (19)                  (3)                    (22)
           -----------------------------------------------------------------------------------------------------
           Balance at March 31, 2001                         $ 45                 $  3                   $  48
           -----------------------------------------------------------------------------------------------------


All of Aon's unpaid liabilities relating to the business transformation plan are
reflected  in  general  expense   liabilities  in  the  condensed   consolidated
statements of financial position.


10.      Income Per Share
         ----------------

         Income per share is calculated as follows:



                                                                      First Quarter Ended March 31,
                                                                      -----------------------------
                (millions except per share data)                         2001               2000
                -----------------------------------------------------------------------------------

                                                                                       
                Net income                                             $   19              $   116
                Redeemable preferred stock dividends                        1                    1
                                                                       ----------------------------
                Net income  for dilutive and basic                     $   18              $   115
                                                                       ============================

                Basic shares outstanding                                  265                  259
                Common stock equivalents                                    3                    1
                                                                       ----------------------------
                Dilutive potential common shares                          268                  260
                -----------------------------------------------------------------------------------
                Basic net income per share                             $ 0.07              $  0.44
                Dilutive net income per share                          $ 0.07              $  0.44
                -----------------------------------------------------------------------------------



11.      Alexander & Alexander Services Inc. (A&A) Discontinued Operations
         -----------------------------------------------------------------

         A&A  discontinued  its  property and  casualty  insurance  underwriting
         operations in 1985,  some of which were then placed into run-off,  with
         the  remainder  sold in 1987.  In  connection  with  those  sales,  A&A
         provided  indemnities  to the  purchasers  for  various  estimated  and
         potential  liabilities,  including  provisions  to cover future  losses
         attributable to insurance pooling arrangements, a stop-loss reinsurance
         agreement,  and actions or omissions by various  underwriting  agencies
         previously  managed by an A&A  subsidiary.  As of March 31,  2001,  the
         liabilities  associated with the foregoing

                                     - 10 -

         indemnities and liabilities of insurance underwriting subsidiaries that
         are  currently in run-off  were  included in other  liabilities  in the
         accompanying condensed  consolidated  statements of financial position.
         Such  liabilities   amounted  to  $136  million,   net  of  reinsurance
         recoverables   and  other  assets  of  $175   million,   and  would  be
         substantially  reduced if a  February,  2000  ruling  from the Court of
         Appeal in England favorable to A&A, in respect of which right to appeal
         has been granted, were upheld in a decision expected in or around 2002.


12.      Contingencies
         -------------

         Aon  and  its  subsidiaries   are  subject  to  numerous  claims,   tax
         assessments and lawsuits that arise in the ordinary course of business.
         The damages  that may be claimed  are  substantial,  including  in many
         instances  claims for punitive or extraordinary  damages.  Accruals for
         these  items have been  provided  to the extent  that losses are deemed
         probable and are estimable.

         In 1998, the Internal Revenue Service (IRS) proposed adjustments to the
         tax of certain Aon  subsidiaries  for the period of 1990 through  1993.
         Most  of  these   adjustments   should  be  resolved   through  factual
         substantiation  of certain  accounting  matters.  However,  the IRS has
         contended  that  retro-rated   extended   warranty   contracts  do  not
         constitute  insurance  for  tax  purposes.  Accordingly,  the  IRS  has
         proposed  a  deferral  of  deductions  for   obligations   under  those
         contracts. The effect of such deferral would be to increase the current
         tax  obligations  of certain  Aon  subsidiaries  by  approximately  $74
         million,  $3 million,  $5 million and $12 million  (plus  interest)  in
         years 1990, 1991, 1992, and 1993,  respectively.  Aon believes that the
         IRS's position is without merit and inconsistent with numerous previous
         IRS private letter rulings. Aon has commenced an administrative  appeal
         and intends to contest vigorously such treatment.  Aon believes that if
         the contracts  are deemed not to be insurance  for tax  purposes,  they
         would be recharacterized in such a way that the increased taxes for the
         years in question would be far less than the proposed assessments.

         In the second quarter of 1999,  Allianz Life Insurance Company of North
         America,  Inc.  ("Allianz")  filed an amended  complaint  in  Minnesota
         adding a brokerage  subsidiary of Aon as a defendant in an action which
         Allianz brought against three insurance  carriers reinsured by Allianz.
         These three carriers  provided  certain types of workers'  compensation
         reinsurance to a pool of insurers and to certain  facilities managed by
         Unicover  Managers,  Inc.  ("Unicover"),  a New Jersey  corporation not
         affiliated with Aon.  Allianz alleges that the Aon subsidiary  acted as
         an agent of the three  carriers  when placing  reinsurance  coverage on
         their behalf.  Allianz claims that the  reinsurance it issued should be
         rescinded  or that it  should  be  awarded  damages,  based on  alleged
         fraudulent,  negligent and innocent misrepresentations by the carriers,
         through  their  agents,  including the Aon  subsidiary  defendant.  Aon
         believes that the Aon subsidiary has  meritorious  defenses and the Aon
         subsidiary intends to vigorously defend this claim.

         Except for an action filed to compel Aon to produce  documents to which
         Aon  is  responding,  the  Allianz  lawsuit  is  the  only  lawsuit  or
         arbitration  relating to Unicover  in which any  Aon-related  entity is
         currently a party.

         Certain U.K. subsidiaries of Aon have been required by their regulatory
         body, the Personal  Investment  Authority (PIA), to review advice given
         by those  subsidiaries  to individuals  who bought pension plans during
         the period from April 1988 to June 1994. These reviews have resulted in
         a requirement to pay compensation to clients based on guidelines issued
         by the PIA.  Aon's  ultimate  exposure  from the private  pension  plan
         review,  as  presently  calculated,  is subject

                                     - 11 -

         to a number of variable factors including,  among others, general level
         of  pricing  in the  equity  markets,  the  interest  rate  established
         quarterly for calculating compensation, and the precise scope, duration
         and  methodology of the review,  including  whether  recent  regulatory
         guidance will have to be applied to previously settled claims.

         Although the ultimate  outcome of all matters  referred to above cannot
         be ascertained and liabilities in indeterminate  amounts may be imposed
         on Aon or  its  subsidiaries,  on the  basis  of  present  information,
         amounts already provided, availability of insurance coverages and legal
         advice  received,  it is the opinion of management that the disposition
         or  ultimate  determination  of such  claims  will not have a  material
         adverse effect on the consolidated  financial position of Aon. However,
         it is possible that future  results of operations or cash flows for any
         particular  quarterly or annual period could be materially  affected by
         an unfavorable resolution of these matters.


13.      Acquisition
         -----------

         In February  2001,  Aon announced that it had entered into a definitive
         agreement  to acquire ASI  Solutions  Incorporated  (ASI),  a worldwide
         provider of human resources  administration and compensation consulting
         services.   The transaction was  approved  by  ASI's  stockholders  and
         completed on May 9, 2001.  The acquisition was financed by the issuance
         of approximately 3.1 million  shares  of  common  stock  and  has  been
         accounted for as a purchase.

                                     - 12 -



                                 AON CORPORATION
                      MANAGEMENT'S DISCUSSION AND ANALYSIS
                OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

                       FIRST QUARTER ENDED MARCH 31, 2001


GENERAL
- -------

Aon has three  operating  segments:  Insurance  Brokerage  and  Other  Services,
Consulting and Insurance  Underwriting.  These segments are based on the type of
client and the services or products delivered.  Aon has a fourth,  non-operating
segment, Corporate and Other.

References to organic growth exclude the impact of  acquisitions,  dispositions,
transfers,  investment income, foreign exchange and other unusual items. Written
premiums  are the  basis  for the  measurement  of  organic  growth  within  the
Insurance  Underwriting  segment.  References  to income  before  income tax are
before  minority  interest  related  to  the  issuance  of  8.205%   mandatorily
redeemable preferred capital securities and the cumulative effect of a change in
accounting principle. For purposes of operating segment discussions, comparisons
against 2000 results exclude special charges.

INFORMATION CONCERNING FORWARD-LOOKING STATEMENTS
- -------------------------------------------------

This quarterly  report contains 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 businesses, and the timing and terms associated therewith.

SPIN-OFF OF UNDERWRITING BUSINESSES
- -----------------------------------

As previously  disclosed,  on April 20, 2001, Aon's Board of Directors approved,
in  principle,  a plan to spin-off its  underwriting  businesses to Aon's common
stockholders,  creating two independent, publicly traded companies. The spin-off
would take the form of a tax-free dividend of common stock of the new company 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.  The assets of the new
company,  to  be  called  Combined  Specialty   Corporation,   would  include  a
substantial  portion of the investment  portfolio  reported in the non-operating
segment. The purpose of the spin-off is to provide opportunities for accelerated
revenue and profit growth by providing clients additional products and  services
through expanded distribution channels.

BUSINESS TRANSFORMATION PLAN
- ----------------------------

In  November  2000,  Aon's  Board  of  Directors  approved,   in  principle,   a
comprehensive  business  transformation plan designed to enhance client service,
significantly  improve the way Aon conducts  business and improve  profitability
primarily through utilization of technology and process redesign.

                                     - 13 -

Implementation of the business transformation plan began in fourth quarter 2000.
Aon will incur costs  estimated to be between $250 million and $325 million on a
pretax  basis  comprised  of both  special  charges and  transition  costs.  The
majority of the plan costs and savings  are related to the  Insurance  Brokerage
and Other  Services  segment,  principally  in the U.S. and the United  Kingdom,
where most of Aon's  offices and  employees  are  located.  The  majority of the
charges  involve cash outlays  primarily  for  severance  payments for workforce
reductions  relating to the elimination of about 6% of Aon's worldwide workforce
at the time of the announcement.

In connection  with the plan, Aon recorded pretax special charges of $72 million
($44 million  after tax or $0.16 per share)  during first  quarter  2001.  In an
effort to improve  profitability,  Aon  examined its  marginal  return  non-core
business alliances and took a pretax charge in the quarter of $38 million to end
Aon's  involvement in certain joint ventures and service  partner  relationships
that  did not meet  profitability  hurdles.  These  business  alliances  in 2000
generated  approximately  $42 million in revenue  with  marginal  profitability.
Discontinuing  these alliances will allow management to increase their focus and
capital on Aon's core businesses. Within the core businesses, special charges of
$23 million were incurred which related to termination  benefits.  Approximately
1,200  employees  were  notified  that  their  positions  have  been  or will be
terminated.  For the quarter,  this charge is somewhat less than had  originally
been anticipated due to delays  encountered.  However,  it is still  anticipated
that the remaining  special  charges will be taken by the end of second  quarter
2001.  Special  charges of $11 million were incurred for asset  impairments  and
other charges,  primarily  relating to the abandonment of systems and equipment.
Transition  costs,  primarily  related to our core  operating  businesses,  were
approximately  $3 million in the first quarter and consisted of consultant  fees
and limited retention bonuses and are included in operating expenses.  Timing of
future transition costs will impact future periods.

Annualized  pretax  savings  from the plan are on track and are  estimated to be
approximately $150 million to $200 million. Full-annualized run rate savings are
expected to be achieved  in fourth  quarter  2001.  Savings  generated  in first
quarter 2001 were offset by  transition  costs and  temporary  revenue  declines
related  to the  transformation.  As Aon  progresses  through  the next  several
quarters,  more  business  process  change and  additional  increase in position
eliminations will drive cost savings. As previously noted, temporary pressure on
revenue  growth  rates may continue to occur  during the  implementation  of the
plan.

CONSOLIDATED RESULTS
- --------------------

Total revenue increased $1 million,  essentially flat when compared to the first
quarter 2000.  Excluding the effect of foreign exchange rates,  revenues rose 4%
over the first  quarter  2000,  primarily  attributable  to growth in  brokerage
commissions  and fees and premiums  earned,  which more than offset a decline in
investment  income.   Consolidated  revenue  for  the  operating  segments  grew
approximately 7% on an organic basis over last year.

Brokerage  commissions  and fees  increased  $76 million or 6% in first  quarter
2001, primarily reflecting growth from business combination activity, especially
Actuarial  Sciences  Associates,  Inc.  (ASA)  which was  acquired in the fourth
quarter 2000, internal growth, increased new business and the impact of improved
pricing.

Premiums and other is primarily  related to insurance  underwriting  operations.
Premiums and other  increased $40 million or 9% in first quarter 2001,  compared
with  the  same  period  last  year.  Total  premiums  earned  in the  insurance
underwriting  segment were $508 million,  an increase of $45 million or 10% over
prior year.  The  increase in premiums  earned  primarily  reflects new business
initiatives, continued organic growth and the impact of acquisitions.

                                     - 14 -

Investment  income,  which  includes  related  expenses  and  income  or loss on
disposals and impairments, decreased $115 million in the first quarter 2001 when
compared to prior year,  primarily  reflecting  reduced  valuations  from equity
investments  in limited  partnerships  in the  quarter,  along with the recorded
impairment of certain directly owned equity  investments.  Revenues from private
equity  investments   fluctuate  due  to  the  inherent   volatility  of  equity
investments.  Investment income from insurance brokerage and other services, and
consulting  operations,  primarily  relating to  fiduciary  funds,  increased $3
million in first  quarter  2001  compared to first  quarter  2000 as a result of
increases in net cash flows  provided from  operations,  as interest  rates have
fallen, especially in the U.S. and the U.K.

Total expenses increased $171 million or 11% in first quarter 2001 when compared
to prior year due partially to the inclusion of special  charges in 2001.  Total
expenses,  excluding  these  special  charges,  increased 6%.  General  expenses
increased  $125  million  or 10% in the  quarter  primarily  reflecting  special
charges of $72 million related to the business  transformation  plan, along with
investments in new business  initiatives  and  technology.  A $40 million or 16%
increase in benefits to policyholders was driven by new underwriting initiatives
along with an unusual  increase in warranty claims during the first quarter 2001
related to an isolated  program that will not affect future  quarters.  Interest
expense  increased $5 million or 16% compared to prior year attributed to higher
average debt levels and the  substitution of short-term debt with long-term debt
in second quarter 2000.

Income before income tax declined significantly from $218 million in 2000 to $48
million in 2001, due principally to non-cash investment results (a negative $115
million  change on a  period-to-period  comparison)  and the  inclusion  of 2001
special  charges ($72 million) with no comparable  amount in first quarter 2000,
which were partially offset by improved results in the operating segments.

As a result of these  factors,  first  quarter  2001 net income  declined to $19
million ($0.07 per dilutive  share) compared to $116 million ($0.44 per dilutive
share) in 2000.  In 2000,  the  company  adopted  the  Securities  and  Exchange
Commission's  Staff  Accounting  Bulletin  101,  which  resulted  in a  one-time
cumulative non-cash charge of $7 million after-tax ($0.03 per share).  Basic net
income per share,  including 2001 special charges,  was $0.07 and $0.44 in first
quarter 2001 and 2000, respectively. Dividends on the redeemable preferred stock
have been  deducted from net income to compute  income per share.  The effective
tax rate was 39% for both first quarter 2001 and 2000.

OPERATING SEGMENTS
- ------------------

INSURANCE BROKERAGE AND OTHER SERVICES
- --------------------------------------

The Insurance Brokerage and Other Services segment consists principally of Aon's
retail  brokerage,  reinsurance,  wholesale  and  specialty  brokerage and other
related   services   such  as  managing   underwriting   and  claims   services.
Approximately 62% of Aon's total revenues are generated from this segment.

First  quarter 2001  Insurance  Brokerage  and Other  Services  revenue was $1.1
billion,  up 4% over last year.  Excluding foreign  exchange,  revenues rose 8%,
reflecting strong organic growth, especially in the international, wholesale and
reinsurance  brokerage and claims services sectors.  Investment income accounted
for $3 million of the  improvement  as a result of  increases  in net cash flows
provided from operations,  as interest rates have fallen, especially in the U.S.
and the U.K.

U.S.  revenue of $541 million in 2001 was up 3% from 2000 due to  increased  new
business,   growth  in  U.S.   specialty   operations,   improved   pricing  and
acquisitions,  which more than  offset the  direct  and  indirect  impact of the
business transformation plan. As anticipated,  new account generation during the
quarter grew at a slower rate in certain retail  brokerage  units as operational
changes were  implemented  to achieve  long-term

                                     - 15 -

benefits of the plan.  Premium  rates  increased  across all major  property and
casualty  lines and  clients  continued  to utilize  alternative  risk  transfer
services to minimize price  increases.  U. K. and Continent of Europe revenue of
$445  million  increased  4% from 2000,  primarily  due to  internal  growth and
acquisitions. The impact of foreign exchange rates partially offset this revenue
growth.  Rest of world revenue increased $11 million or 9% due to strong organic
growth, new business, and to a lesser extent, the impact of acquisitions. In the
international  retail  brokerage  operations,   premium  rate  comparisons  have
remained about the same as fourth quarter 2000 but are improved over last year's
first quarter.

Pretax income was $126 million for the first quarter 2001. Excluding this year's
special charges, pretax income of $196 million rose 9% over 2000. Pretax margins
before  special  charges in this segment  were 17.6% in the quarter  compared to
16.8% in 2000.  The  margin  improvement  year over year was driven in part from
business  transformation  savings,  but was  negatively  impacted by a temporary
reduction in the rate of new account growth,  transition costs and an increasing
percentage of lower margin claims service business.

CONSULTING
- ----------

The  consulting  segment  provides  a full  range  of  services  related  to the
management of human capital, benefits and business processes. These services are
delivered to a predominately corporate clientele utilizing four practice groups:
employee benefits, compensation,  management consulting and employment practices
outsourcing.  Approximately  12% of Aon's total revenues are generated from this
segment.

First quarter 2001 revenue  increased 20% to $212 million.  Excluding the impact
of a strong  U.S.  dollar,  revenues  grew  24%.  Revenue  grew 8% in 2001 on an
organic basis.  On a global basis,  the improvement in revenue was influenced by
acquisition  activity,  especially  the  inclusion  of ASA,  acquired  in fourth
quarter 2000,  along with organic  growth,  as client demand for solutions  that
enhance workforce productivity continued.

U.S.  revenue  of $135  million  in 2001 was up 36%  from  2000  reflecting  the
acquisition  of ASA and growth in  compensation  consulting.  U.K.  and European
revenue of $58  million  fell 5% from 2000.  U.K.  revenue  declined 8% from the
prior period reflecting the sale of the financial planning  consulting  business
last year,  along with unfavorable  foreign exchange rates.  Continent of Europe
revenue was flat compared to the first quarter of 2000.

Pretax  income  was $24  million,  a 26%  increase  over  last  year's  results.
Excluding this year's special charges, pretax income improved 32% to $25 million
from $19  million  in first  quarter  2000 as  revenue  growth  outpaced  higher
staffing  costs,  driven by the inclusion of the ASA  acquisition as well as the
growth of the business,  and higher  technology  costs.  Pretax  margins in this
segment  before special  charges were 11.8% in the quarter  compared to 10.8% in
2000.

INSURANCE UNDERWRITING
- ----------------------

The Insurance  Underwriting segment provides life, accident and health insurance
coverage  through  distribution  networks,  most of which are directly  owned by
Aon's  subsidiaries,  and extended warranty and property and casualty  insurance
products.  Approximately  31% of Aon's total  revenues are  generated  from this
segment.

Revenue was $567 million in first quarter  2001, up 7% from 2000.  Excluding the
impact of foreign exchange,  revenue growth was 11%.  Improvement over last year
was driven by the  development  of new  product  initiatives,  higher  volume of
business in the electronics  extended warranty and specialty  casualty areas and
accident and health  products,  which continued to expand  distribution  through
worksite  marketing

                                     - 16 -

programs.  This  growth  more than  offset the loss of certain  accounts  in the
mechanical and special warranty businesses.

U.S.  revenue of $406  million was up 8% in first  quarter 2001 due to growth in
revenues for accident and health, due in part to acquired business,  new product
initiatives,  and electronics  extended  warranty  products.  United Kingdom and
Continent of Europe  revenue of $108  million rose 4%, as organic  growth in the
accident and health sector was partially offset by unfavorable  foreign exchange
rates.  Rest of world revenue was $53 million,  up 6% from prior year reflecting
growth in Latin America.

Pretax income before  special  charges was $68 million in first quarter 2001, up
2% from $67 million last year.  Margins declined  slightly from 12.6% in 2000 to
12% this  year.  New  underwriting  initiatives  drove  premium  growth but also
resulted in increased  benefits to  policyholders.  Also, an unusual increase in
warranty  claims  occurred  during the first quarter 2001 related to an isolated
program that will not affect future quarters.

NON-OPERATING SEGMENT
- ---------------------

CORPORATE AND OTHER
- -------------------

Revenue in this  category  consists  primarily of investment  income  (including
income  or loss  on  disposals,  along  with  impairment  losses)  which  is not
otherwise  reflected in the results of the operating  segments.  Invested assets
and related  investment  income not directly  required to support the  insurance
brokerage and consulting  businesses,  together with the assets in excess of net
policyholder  liabilities of the underwriting businesses and related income, are
allocated to the  Corporate  and Other  segment.  Corporate  operating  expenses
include administrative and certain information technology costs.

Corporate and Other revenue was a negative $85 million in 2001,  versus positive
revenue of $30 million in the first quarter 2000,  primarily  reflecting reduced
valuations for equity investments in limited partnerships in the quarter,  along
with the  write-down  of  certain  directly-owned  equity  investments.  Limited
partnership  investments have historically provided higher returns over a longer
time horizon than broad market common stock returns.  However, in the short run,
the returns are inherently more variable.

Corporate  and Other  expenses for the quarter  were $84 million,  up $6 million
from the same  period  last year.  Expenses  in this  segment  are  composed  of
interest expense,  goodwill amortization and general expenses.  Interest expense
rose $5 million or 16% compared to prior year,  reflecting  higher  average debt
levels and an  extension  of debt  duration  in second  quarter  2000.  Goodwill
amortization  rose $2 million  as a result of new  acquisitions,  while  general
expenses fell $1 million, resulting from lower technology costs.

The revenue and expense  comparisons  discussed above contributed to the overall
corporate and other pretax loss of $169 million in the quarter  versus a loss of
$48 million last year.

                                     - 17 -

                        CASH FLOW AND FINANCIAL POSITION
                        AT THE END OF FIRST QUARTER 2001


Cash flows from operating  activities  represent the net income earned by Aon in
the reported  periods  adjusted  for non-cash  charges and changes in assets and
liabilities.  Cash flows provided by operating  activities in first quarter 2001
were $332 million,  a $186 million  increase  over the same period in 2000.  The
increase  represents, in part, the timing of payment for incentive compensation.
Also, working capital improved due to fiduciary funds availability. In addition,
the non-cash  effect of lower  valuations on the company's  limited  partnership
portfolio,  coupled with  impairments  on  investments  and losses on disposals,
contributed to lower net income. The cash impact of special charges and purchase
accounting  liabilities  in 2001 was similar to what was spent last year.  First
quarter 2001  reflects  the pretax  special  charges of $72  million,  less cash
expended. First quarter 2000 reflects only actual payments on special charge and
purchase accounting liabilities previously established.

Investing  activities  used  cash of $186  million.  Cash  of $103  million  was
provided during first quarter 2001 from the net sale of other investments.  This
was offset by the net purchase of short-term  investments of $180 million.  Cash
used for  acquisition  activity  during  first  quarter  2001  was $44  million,
primarily reflecting brokerage acquisitions.

Cash of  $376  million  was  used  during  first  quarter  2001  from  financing
activities,  which was $235 million  more than was utilized in 2000.  The higher
usage of cash from prior year is  primarily  due to a  reduction  of  short-term
borrowings  in 2001 versus an increase in  short-term  debt during first quarter
2000.  Cash was used to pay  dividends  of $57  million  on common  stock and $1
million on  redeemable  preferred  stock  during  first  quarter  2001.  Various
regulatory  requirements  applied to Aon's underwriting and overseas  operations
limit availability of operating cash flows for general corporate purposes.

Aon's operating subsidiaries anticipate that there will be adequate liquidity to
meet their needs in the foreseeable future.  Aon's liquidity needs are primarily
for  servicing  its debt and for the payment of  dividends  on stock  issues and
capital securities.  The businesses of Aon's operating  subsidiaries continue to
provide  substantial  positive  cash  flow.  Brokerage  cash  flow has been used
primarily  for  business  reinvestment,  acquisition  financing  and payments of
special charge and purchase accounting liabilities. Aon anticipates continuation
of the  company's  positive  cash flow and the ability of the parent  company to
access adequate  short-term lines of credit.  Aon anticipates a sufficient level
of  future  operating  cash  flows  to  offset  cash  payments  related  to both
restructuring   charges  and  transition  costs  associated  with  the  business
transformation plan.

Due to the contractual nature of its insurance policyholder  liabilities,  which
are primarily intermediate to long-term in nature, Aon has invested primarily in
fixed  maturities.  With a carrying  value of $2.3  billion,  Aon's  total fixed
maturity  portfolio is invested primarily in investment grade holdings (95%) and
has a fair value which is 99.9% of amortized cost at March 31, 2001.

Total assets decreased $214 million since year-end 2000 to $22 billion. Invested
assets at March 31, 2001  increased $60 million from year-end  levels  primarily
from higher levels of short-term  investments and equity  securities  which were
offset in part by lower valuations and impairment  charges in other investments.
The amortized cost and fair value of less than  investment  grade fixed maturity
investments at March 31, 2001 were $129 million and $115 million,  respectively.
The carrying value of non-income  producing  investments  in Aon's  portfolio at
March 31, 2001 was $65 million, or 1.1% of total invested assets.

                                     - 18 -

Short-term borrowings decreased at the end of first quarter 2001 by $249 million
when  compared to year-end  2000.  Notes  payable  increased at the end of first
quarter  2001 by $6 million  when  compared to  year-end  2000,  reflecting  the
issuance of  additional  debt.  Approximately  $12  million of notes  payable is
scheduled to be paid within one year.

Stockholders' equity decreased $25 million in first quarter 2001, reflecting net
foreign exchange losses of $43 million and dividends paid to stockholders of $58
million.  Partially  offsetting  this  decline was the net  decrease in treasury
stock of $37 million and net income of $19 million.  Unrealized investment gains
and losses and foreign  exchange  gains and losses  fluctuations  from period to
period are largely based on market conditions.

Stockholders'  equity per share  declined  from $13.02 at  December  31, 2000 to
$12.84 at March 31, 2001,  reflecting  both the decline in the equity balance as
well as an increase in the number of common shares outstanding.

REVIEW BY INDEPENDENT AUDITORS
- ------------------------------

The condensed  consolidated  financial  statements at March 31, 2001 and for the
first quarter then ended have been reviewed,  prior to filing,  by Ernst & Young
LLP, Aon's independent auditors, and their report is included herein.

                                     - 19 -

INDEPENDENT ACCOUNTANTS' REVIEW REPORT



Board of Directors and Stockholders
Aon Corporation

We have reviewed the accompanying  condensed consolidated statement of financial
position of Aon  Corporation  as of March 31,  2001,  and the related  condensed
consolidated  statements  of income and cash flows for the  three-month  periods
ended March 31, 2001 and 2000. These financial statements are the responsibility
of the Company's management.

We  conducted  our  reviews in  accordance  with  standards  established  by the
American  Institute  of  Certified  Public  Accountants.  A  review  of  interim
financial  information consists principally of applying analytical procedures to
financial  data, and making  inquiries of persons  responsible for financial and
accounting matters. It is substantially less in scope than an audit conducted in
accordance  with auditing  standards  generally  accepted in the United  States,
which will be performed  for the full year with the  objective of  expressing an
opinion regarding the financial statements taken as a whole. Accordingly,  we do
not express such an opinion.

Based on our reviews, we are not aware of any material modifications that should
be made to the accompanying condensed consolidated financial statements referred
to above  for them to be in  conformity  with  accounting  principles  generally
accepted in the United States.

We have  previously  audited,  in accordance with auditing  standards  generally
accepted in the United States, the consolidated  statement of financial position
of Aon  Corporation  as of  December  31,  2000,  and the  related  consolidated
statements  of income,  stockholders'  equity,  and cash flows for the year then
ended,  not  presented  herein,  and in our report  dated  February 8, 2001,  we
expressed an unqualified opinion on those consolidated financial statements.  In
our  opinion,   the  information  set  forth  in  the   accompanying   condensed
consolidated  statement of financial position as of December 31, 2000, is fairly
stated, in all material respects,  in relation to the consolidated  statement of
financial position from which it has been derived.




                                                             ERNST & YOUNG LLP

Chicago, Illinois
May 9, 2001

                                     - 20 -


                                     PART II
                                     -------

                                OTHER INFORMATION
                                -----------------


ITEM 4.                  SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS

          (a)            The Annual  Meeting of Stockholders  of the  Registrant
                         was held on April 20, 2001 (the "2001 Annual Meeting").

          (b)            Not applicable.





          (c)(i)         Name                                          For                           Against
                         ----                                          ---                           -------

                                                                                              
                         Franklin A. Cole                          230,333,000                      2,173,981
                         Edgar D. Jannotta                         230,374,240                      2,132,741
                         Lester B. Knight                          230,418,603                      2,088,378
                         Perry J. Lewis                            230,407,554                      2,099,427
                         Andrew J. McKenna                         230,351,122                      2,155,859
                         Robert S. Morrison                        230,398,763                      2,108,218
                         Richard C. Notebaert                      230,392,437                      2,114,544
                         Michael D. O'Halleran                     230,333,517                      2,173,464
                         Donald S. Perkins                         230,334,358                      2,172,623
                         John W. Rogers, Jr.                       230,448,048                      2,058,933
                         Patrick G. Ryan                           230,399,284                      2,107,697
                         George A. Schaefer                        230,346,608                      2,160,373
                         Raymond I. Skilling                       230,378,717                      2,128,264
                         Fred L. Turner                            230,394,229                      2,112,752
                         Arnold R. Weber                           230,335,897                      2,171,084
                         Carolyn Y. Woo                            209,812,702                     22,694,279



             (ii)        Set forth below is the  tabulation  of  the vote on the
                         approval  of  the  Aon  Stock  Incentive  Plan,   which
                         includes provisions qualifying the plan  for  favorable
                         treatment under Section  162(m) of the Internal Revenue
                         Code.



                                    For                Against                 Abstain               Non-Vote
                                    ---                -------                 -------               --------
                                                                                           
                                133,593,506           78,059,665              1,963,719             18,890,091



             (iii)       Set forth  below is the  tabulation  of the vote on the
                         adoption  of  the  amendment  of  the   Senior  Officer
                         Incentive Compensation  Plan which includes  provisions
                         qualifying  that  plan  for  favorable treatment  under
                         Section 162(m)  of  the  Internal Revenue Code.



                                    For                 Against                Abstain
                                    ---                 -------                -------
                                                                        
                                223,697,019             6,557,479             2,252,483


                                     - 21 -

             (iv)        Set forth below is the tabulation  of  the vote on  the
                         selection of Ernst  &  Young  LLP  as auditors for  the
                         Registrant for the 2001 fiscal year.




                                      For                   Against            Abstain
                                      ---                   -------            -------
                                                                        
                                  230,530,164              1,009,525           967,292



          (d)            Not applicable.




ITEM 6.           EXHIBITS AND REPORTS ON FORM 8-K

         (a)      Exhibits - The  exhibits  filed with this report are listed on
                  --------
                  the attached Exhibit Index.

         (b)      Reports  on Form  8-K -
                  ----------------------

                  (i)    No Current Reports  on  Form  8-K  were  filed for  the
                         quarter ended March 31, 2001.

                  (ii)   The Registrant filed one current  report  on  Form  8-K
                         dated  April  20,  2001.   The  following  exhibit  was
                         included  in the  report:  Exhibit 99 -  Press  Release
                         issued on April 20, 2001.

SIGNATURE

Pursuant to the  requirements  of the  Securities  and 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
                                    ---------------
                                    (Registrant)


May 14, 2001                        /s/ Harvey N. Medvin
                                    ---------------------
                                    HARVEY N. MEDVIN
                                    EXECUTIVE VICE PRESIDENT AND
                                    CHIEF FINANCIAL OFFICER
                                    (Principal Financial and Accounting Officer)


                                     - 22 -

Aon CORPORATION
- ---------------

Exhibit Number
In Regulation S-K


Item 601 Exhibit Table
- ----------------------



(12) Statements regarding Computation of Ratios.

         (a)      Statement regarding  Computation of Ratio of Earnings to Fixed
                  Charges.

         (b)      Statement regarding  Computation   of  Ratio  of  Earnings  to
                  Combined Fixed Charges and Preferred Stock Dividends.


(15) Letter re: Unaudited Interim Financial Information


                                     - 23 -



                                                                                                               EXHIBIT 12(a)
                                  Aon CORPORATION AND CONSOLIDATED SUBSIDIARIES
                                    COMBINED WITH UNCONSOLIDATED SUBSIDIARIES
                                Computation of Ratio of Earnings to Fixed Charges


                                                THREE MONTHS ENDED
                                                     MARCH 31,                     YEARS ENDED DECEMBER 31,
                                               --------------------- --------------------------------------------------------
 (millions except ratios)                        2001        2000       2000       1999        1998       1997        1996
                                               ---------  ---------- ----------  ---------  ----------  ---------  ----------

                                                                                                  
 Income from continuing operations
    before provision for income taxes (1)         $  48       $ 218    $   854      $ 635     $   931      $ 542       $ 446

 ADD BACK FIXED CHARGES:

    Interest on indebtedness                         36          31        140        105          87         70          45

    Interest on ESOP                                  -           -          -          1           2          3           4

    Portion of rents representative of
      interest factor                                14          12         54         49          51         44          29

                                               ---------  ---------- ----------  ---------  ----------  ---------  ----------
         INCOME AS ADJUSTED                       $  98       $ 261    $ 1,048      $ 790     $ 1,071      $ 659       $ 524
                                               =========  ========== ==========  =========  ==========  =========  ==========


 FIXED CHARGES:

    Interest on indebtedness                      $  36       $  31    $   140      $ 105        $ 87      $  70       $  45

    Interest on ESOP                                  -           -          -          1           2          3           4

    Portion of rents representative of
       interest factor                               14          12         54         49          51         44          29

                                               ---------  ---------- ----------  ---------  ----------  ---------  ----------
         TOTAL FIXED CHARGES                      $  50       $  43    $   194      $ 155     $   140      $ 117       $  78
                                               =========  ========== ==========  =========  ==========  =========  ==========

 RATIO OF EARNINGS TO FIXED CHARGES                 2.0         6.1        5.4        5.1         7.6        5.6         6.7
                                               =========  ========== ==========  =========  ==========  =========  ==========
<FN>
(1)  Income from  continuing  operations  before  provision for income taxes and
     minority  interest  includes  special  charges of $72 million for the three
     months ended March 31, 2001 and $82 million, $313 million, $172 million and
     $90 million for the years ended  December  31, 2000,  1999,  1997 and 1996,
     respectively.
</FN>





                                                                                                                  EXHIBIT 12(b)

                                   Aon CORPORATION AND CONSOLIDATED SUBSIDIARIES
                                     COMBINED WITH UNCONSOLIDATED SUBSIDIARIES
                            Computation of Ratio of Earnings to Combined Fixed Charges
                                          and Preferred Stock Dividends


                                                  THREE MONTHS ENDED
                                                      MARCH 31,                        YEARS ENDED DECEMBER 31,
                                                ---------------------- ----------------------------------------------------------
(millions except ratios)                           2001        2000        2000        1999        1998         1997       1996
                                                ----------  ---------- ----------- ----------  ----------  ---------- -----------

                                                                                                      
 Income from continuing operations
    before provision for income taxes (1)            $ 48       $ 218     $   854      $ 635     $   931       $ 542       $ 446

 ADD BACK FIXED CHARGES:

    Interest on indebtedness                           36          31         140        105          87          70          45

    Interest on ESOP                                    -           -           -          1           2           3           4

    Portion of rents representative of
      interest factor                                  14          12          54         49          51          44          29

                                                ----------  ---------- ----------- ----------  ----------  ---------- -----------
         INCOME AS ADJUSTED                          $ 98       $ 261     $ 1,048      $ 790     $ 1,071       $ 659       $ 524
                                                ==========  ========== =========== ==========  ==========  ========== ===========


 FIXED CHARGES AND PREFERRED STOCK DIVIDENDS:

    Interest on indebtedness                         $ 36       $  31     $   140      $ 105     $    87       $  70       $  45

    Preferred stock dividends                          17          17          70         70          70          82          29

                                                ----------  ---------- ----------- ----------  ----------  ---------- -----------
         INTEREST AND DIVIDENDS                        53          48         210        175         157         152          74

    Interest on ESOP                                    -           -           -          1           2           3           4

    Portion of rents representative of
       interest factor                                 14          12          54         49          51          44          29

                                                ----------  ---------- ----------- ----------  ----------  ---------- -----------
         TOTAL FIXED CHARGES AND PREFERRED
             STOCK DIVIDENDS                         $ 67       $  60     $   264      $ 225     $   210       $ 199       $ 107
                                                ==========  ========== =========== ==========  ==========  ========== ===========

 RATIO OF EARNINGS TO COMBINED FIXED
   CHARGES AND PREFERRED STOCK DIVIDENDS (2)          1.5         4.4         4.0        3.5         5.1         3.3         4.9
                                                ==========  ========== =========== ==========  ==========  ========== ===========

<FN>
(1)  Income from  continuing  operations  before  provision for income taxes and
     minority  interest  includes  special  charges of $72 million for the three
     months ended March 31, 2001 and $82 million, $313 million, $172 million and
     $90 million for the years ended  December  31, 2000,  1999,  1997 and 1996,
     respectively.

(2)  Included  in total fixed  charges and  preferred  stock  dividends  are $16
     million for the three months ended March 31, 2001 and 2000, $66 million for
     the years ended  December 31, 2000,  1999 and 1998, and $64 million for the
     year  ended  December  31,  1997,  of pretax  distributions  on the  8.205%
     mandatorily redeemable preferred capital securities which are classified as
     "minority interest" on the condensed consolidated statements of income.
</FN>




                                                                      Exhibit 15




Board of Directors and Stockholders
Aon Corporation


We are aware of the incorporation by reference in the Registration Statements of
Aon Corporation ("Aon") described in the following table of our report dated May
9, 2001  relating to the  unaudited  condensed  consolidated  interim  financial
statements of Aon Corporation that are included in its Form 10-Q for the quarter
ended March 31, 2001:

          Registration Statement
          ----------------------
         Form            Number                       Purpose
         ----            ------                       -------

         S-8          33-27984       Pertaining to Aon's savings plan
         S-8          33-42575       Pertaining to Aon's  stock award  plan  and
                                          stock option plan
         S-8          33-59037       Pertaining to Aon's  stock award  plan  and
                                          stock option plan
         S-4          333-21237      Offer to exchange Capital Securities of Aon
                                          Capital A
         S-3          333-50607      Pertaining  to the registration of  369,000
                                          shares of common stock
         S-8          333-55773      Pertaining to Aon's stock award plan, stock
                                          option   plan   and   employee   stock
                                          purchase plan
         S-3          333-78723      Pertaining  to  the  registration  of  debt
                                          securities, preferred stock and common
                                          stock
         S-3          333-49300      Pertaining to the registration of 3,864,824
                                          shares of common stock
         S-4          333-57706      Pertaining   to   the   registration  of  a
                                          proposed issuance of up  to  3,852,184
                                          shares  of   common   stock   to   the
                                          stockholders of ASI Solutions, Inc.

Pursuant to Rule 436(c) of the  Securities Act of 1933, our report is not a part
of the registration  statements  prepared or certified by accountants within the
meaning of Section 7 or 11 of the Securities Act of 1933.


                                                           ERNST & YOUNG LLP



Chicago, Illinois
May 9, 2001