<PAGE>   1
                                             Filed pursuant to Rule 424(b)(2)
                                             Registration No. 33-51609
PROSPECTUS SUPPLEMENT
(To Prospectus Dated January 5, 1994)
 
THE PROGRESSIVE CORPORATION
 
$200,000,000
 
6.60% Notes due 2004
 
Interest payable January 15 and July 15
 
ISSUE PRICE:  99.854%
 
The Notes will bear interest from January 12, 1994, at the rate of 6.60% per
annum, payable semiannually on January 15 and July 15, commencing July 15, 1994.
The Notes will not be redeemable prior to maturity and will not be subject to
any sinking fund. See "Certain Terms of Notes."
 
The Notes will be represented by one or more global notes ("Global Notes"),
which will be deposited with The Depository Trust Company (the "Depositary") and
will be registered in the name of its nominee. Beneficial ownership of the Notes
will be limited to institutions that have accounts with the Depositary
("Participants") or persons that hold interests through Participants. A
beneficial interest in a Global Note will be shown on, and transfers thereof
will be effected only through, records maintained by the Participants. A
beneficial interest in a Global Note will be exchanged for Notes in certificated
form only under the limited circumstances described herein. The Notes will trade
in the Depositary's Same-Day Funds Settlement System, and settlement of any
secondary market trading activity for the Notes will therefore settle in
immediately available funds. See "Certain Terms of Notes--Book-Entry System."
 
THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND
EXCHANGE COMMISSION, ANY STATE SECURITIES COMMISSION OR THE NORTH CAROLINA
INSURANCE COMMISSIONER NOR HAS THE SECURITIES AND EXCHANGE COMMISSION, ANY STATE
SECURITIES COMMISSION OR SUCH COMMISSIONER PASSED UPON THE ACCURACY OR ADEQUACY
OF THIS PROSPECTUS SUPPLEMENT OR THE PROSPECTUS. ANY REPRESENTATION TO THE
CONTRARY IS A CRIMINAL OFFENSE.
 
- --------------------------------------------------------------------------------
 

<TABLE>
<CAPTION>
                                                   PRICE TO       UNDERWRITING    PROCEEDS TO
                                                   PUBLIC(1)      DISCOUNT(2)    COMPANY(1)(3)
<S>                                              <C>              <C>            <C>
- ---------------------------------------------
Per Note                                         99.854%          .650%          99.204%
- ---------------------------------------------
Total                                            $199,708,000     $1,300,000     $198,408,000
</TABLE>

 
- --------------------------------------------------------------------------------
 
(1) Plus accrued interest, if any, from January 12, 1994.
 
(2) The Company has agreed to indemnify the Underwriter against certain
    liabilities, including liabilities under the Securities Act of 1933, as
    amended. See "Underwriting."
 
(3) Before deducting net expenses payable by the Company estimated at $265,000.
    See "Underwriting."
 
The Notes are offered, subject to prior sale, when, as and if accepted by the
Underwriter and subject to approval of certain legal matters by Stroock &
Stroock & Lavan, counsel for the Underwriter. It is expected that delivery of
the Global Notes will be made on or about January 12, 1994, through the
facilities of the Depositary, against payment therefor in same-day funds.
 
J.P. MORGAN SECURITIES INC.
 
January 5, 1994

<PAGE>   2
 
     IN CONNECTION WITH THIS OFFERING, THE UNDERWRITER MAY OVER-ALLOT OR EFFECT
TRANSACTIONS WHICH STABILIZE OR MAINTAIN THE MARKET PRICE OF THE NOTES OFFERED
HEREBY AT A LEVEL ABOVE THAT WHICH MIGHT OTHERWISE PREVAIL IN THE OPEN MARKET.
SUCH STABILIZING, IF COMMENCED, MAY BE DISCONTINUED AT ANY TIME.
 
     NO PERSON HAS BEEN AUTHORIZED TO GIVE ANY INFORMATION OR TO MAKE ANY
REPRESENTATION NOT CONTAINED OR INCORPORATED BY REFERENCE IN THIS PROSPECTUS
SUPPLEMENT OR THE ACCOMPANYING PROSPECTUS AND, IF GIVEN OR MADE, SUCH
INFORMATION OR REPRESENTATION MUST NOT BE RELIED UPON AS HAVING BEEN AUTHORIZED
BY THE COMPANY OR ANY UNDERWRITER, DEALER OR AGENT. NEITHER THE DELIVERY OF THIS
PROSPECTUS SUPPLEMENT OR THE ACCOMPANYING PROSPECTUS NOR ANY SALE MADE HEREUNDER
OR THEREUNDER SHALL, UNDER ANY CIRCUMSTANCES, CREATE ANY IMPLICATION THAT THE
INFORMATION CONTAINED HEREIN OR IN THE ACCOMPANYING PROSPECTUS IS CORRECT AS OF
ANY DATE SUBSEQUENT TO THE DATE HEREOF OR THEREOF OR THAT THERE HAS BEEN NO
CHANGE IN THE AFFAIRS OF THE COMPANY SINCE THE DATE HEREOF OR THEREOF. NEITHER
THIS PROSPECTUS SUPPLEMENT NOR THE ACCOMPANYING PROSPECTUS CONSTITUTES AN OFFER
TO SELL OR A SOLICITATION OF AN OFFER TO BUY NOTES IN ANY JURISDICTION IN WHICH
SUCH OFFER OR SOLICITATION IS NOT AUTHORIZED OR IN WHICH THE PERSON MAKING SUCH
OFFER OR SOLICITATION IS NOT QUALIFIED TO DO SO OR TO ANY PERSON TO WHOM IT IS
UNLAWFUL TO MAKE SUCH OFFER OR SOLICITATION.
 
                               TABLE OF CONTENTS
 

<TABLE>
<CAPTION>
                                                                                       PAGE
                                                                                       -----
<S>                                                                                    <C>
PROSPECTUS SUPPLEMENT
Capitalization.........................................................................  S-3
Certain Terms of Notes.................................................................  S-4
Underwriting...........................................................................  S-6
PROSPECTUS
Available Information..................................................................    2
Incorporation of Certain Documents by Reference........................................    2
The Company............................................................................    3
Use of Proceeds........................................................................    3
Selected Consolidated Financial Information............................................    4
Description of Debt Securities.........................................................    6
Plan of Distribution...................................................................   10
Legal Matters..........................................................................   11
Experts................................................................................   11
</TABLE>

 
                                       S-2

<PAGE>   3
 
                                 CAPITALIZATION
 
     The following table sets forth the capitalization of the Company at
September 30, 1993, as adjusted to reflect the issuance of the Notes offered
hereby and to give effect to the repayment of the outstanding indebtedness under
the Company's revolving credit agreements and credit facilities, the October 6,
1993 issuance of 7% Notes due 2013, and the December 17, 1993 redemption of
8 3/4% Debentures due 2017.
 

<TABLE>
<CAPTION>
                                                                         SEPTEMBER 30, 1993
                                                                      ------------------------
                                                                       ACTUAL      AS ADJUSTED
                                                                      --------     -----------
                                                                           (IN MILLIONS)
<S>                                                                   <C>          <C>
Funded debt(1):
  Revolving credit agreements(2)....................................  $   50.0      $      --
  Credit facilities(2)..............................................     120.0             --
  6.60% Notes.......................................................        --          198.4
  7% Notes..........................................................        --          148.2
  8 3/4% Debentures(2)..............................................      69.8             --
  8 3/4% Notes......................................................      28.7           28.7
  10% Notes.........................................................     149.3          149.3
  10 1/8% Subordinated Notes........................................     149.2          149.2
  Other funded debt.................................................       1.6            1.6
                                                                      --------     -----------
       Total funded debt............................................     568.6          675.4
                                                                      --------     -----------
Shareholders' equity:
  9 3/8% Serial Preferred Shares, Series A, issued and outstanding
     3.8............................................................      91.7           91.7
  Common Shares, $1.00 par value, issued and outstanding 72.1.......      72.1           72.1
  Paid-in capital...................................................     353.4          353.4
  Net unrealized appreciation on investments........................      33.2           33.2
  Retained earnings.................................................     403.1          402.9
                                                                      --------     -----------
       Total shareholders' equity...................................     953.5          953.3
                                                                      --------     -----------
Total funded debt and shareholders' equity..........................  $1,522.1      $ 1,628.7
                                                                      --------     -----------
                                                                      --------     -----------
</TABLE>

 
- ---------------
 
(1) See Note 4 to the Company's annual consolidated financial statements
    incorporated herein by reference for information regarding the Company's
    outstanding funded debt.
 
(2) During the fourth quarter of 1993, the Company repaid the outstanding
    indebtedness under its revolving credit agreements and credit facilities and
    redeemed its 8 3/4% Debentures with funds generated from the sale of certain
    securities held in the Company's investment portfolios.
 
                                       S-3

<PAGE>   4
 
                             CERTAIN TERMS OF NOTES
 
     The following summary of the terms of the Notes offered hereby (included in
the defined term "Debt Securities" in the Prospectus) supplements, and to the
extent inconsistent therewith replaces, the description of the general terms and
provisions of Debt Securities set forth in the Prospectus, to which description
reference is hereby made.
 
GENERAL
 
     The 6.60% Notes due 2004 (the "Notes") offered hereby are an issue of the
Debt Securities described in the Prospectus and will be issued as a separate
series of Debt Securities under the Indenture dated as of September 15, 1993
(the "Indenture") entered into between the Company and The First National Bank
of Boston, as Trustee (the "Trustee"). The Notes are limited to an aggregate
principal amount of $200,000,000. In addition to the Notes, the Company may
issue from time to time other series of Debt Securities under the Indenture
consisting of debentures, notes or other unsecured evidences of indebtedness,
but such other series will be separate from and independent of the Notes. The
Indenture does not limit the amount of Debt Securities or any other debt which
may be incurred by the Company. In addition, the provisions of the Indenture do
not afford holders of the Notes protection in the event of a highly leveraged
transaction, reorganization, restructuring, merger or similar transaction
involving the Company that may adversely affect holders of the Notes. Under the
Indenture, the Company is entitled to defease the Notes subject to compliance
with the terms of the Indenture. See "Description of Debt
Securities -- Defeasance" in the Prospectus. The Notes are the second series of
Debt Securities to be issued under the Indenture. Reference is made to the
Prospectus for a description of other general terms of the Debt Securities.
 
     The Notes will mature on January 15, 2004. Interest on the Notes will
accrue from January 12, 1994 and will be payable semiannually on January 15 and
July 15, commencing July 15, 1994, to the persons in whose names the Notes are
registered at the close of business on the January 1 or July 1 prior to the
payment date at the annual rate set forth on the cover page of this Prospectus
Supplement. The Notes will be issued as fully registered Notes in denominations
of $1,000 or integral multiples thereof.
 
     The Notes will not be subject to redemption at the option of the Company or
through the operation of a sinking fund.
 
     The Notes will not be listed on a securities exchange.
 
BOOK-ENTRY SYSTEM
 
     The Notes will be represented by one or more fully registered Global Notes
which will be deposited with, or on behalf of, the Depositary and registered in
the name of the Depositary's nominee. Unless and until it is exchanged in whole
or in part for Notes in certificated form, no Global Note may be transferred
except as a whole by the Depositary to a nominee of such Depositary or by a
nominee of such Depositary to such Depositary.
 
     The Depositary has advised the Company as follows: It is a limited-purpose
trust company organized under the New York Banking Law, a "banking organization"
within the meaning of the New York Banking Law, a member of the Federal Reserve
System, a "clearing corporation" within the meaning of the New York Uniform
Commercial Code and a "clearing agency" registered pursuant to the provisions of
Section 17A of the Securities Exchange Act of 1934 (the "Exchange Act"). The
Depositary was created to hold securities for its participating organizations
(the "Participants") and to facilitate the clearance and settlement of
securities transactions between Participants in such securities through
electronic book-entry changes in accounts of its Participants. Participants
include securities brokers and dealers (including the Underwriter), banks, trust
companies, clearing corporations and certain other organizations some of whom or
representatives of which own the Depositary. Access to the Depositary's system
is also available to others such as banks, brokers, dealers and trust companies
that clear through or maintain a custodial relationship with a Participant,
either directly or indirectly ("indirect participants"). Persons who are not
Participants may beneficially own securities held by the Depositary only through
Participants or indirect participants.
 
                                       S-4

<PAGE>   5
 
     The Depositary has advised the Company that upon the issuance of the Global
Notes, the Depositary will credit on its book-entry system the respective
principal amounts of the individual Notes represented by such Global Notes to
the accounts of the appropriate Participants. The accounts to be credited shall
be designated by the Underwriter. Ownership of beneficial interests in the
Global Notes will be limited to Participants or persons that own beneficial
interests through Participants. Ownership of beneficial interests in the Global
Notes will be shown on, and the transfer of that ownership will be effected only
through, records maintained by the Depositary's Participants or persons that
hold through Participants. The laws of some states require that certain
purchasers of securities take physical delivery of such securities. Such laws
may limit the market for beneficial interests in the Global Notes.
 
     So long as the Depositary, or its nominee, is the registered owner of the
Global Notes, the Depositary or its nominee, as the case may be, will be
considered the sole owner or holder of the Global Notes for all purposes under
the Indenture. Except as provided below, owners of beneficial interests in the
Global Notes will not be entitled to have Notes registered in their names, will
not receive or be entitled to receive physical delivery of Notes in certificated
form and will not be considered the owners or holders thereof under the
Indenture. Accordingly, each person owning a beneficial interest in the Global
Notes must rely on the procedures of the Depositary and, if such person is not a
Participant, on the procedures of the Participant through which such person owns
its interest, to exercise any rights of a holder under the Indenture. The
Company understands that under existing industry practices, in the event that
the Company requests any consent or action of holders or if an owner of a
beneficial interest in the Global Notes desires to give a consent or take any
action which a holder is entitled to give or take under the Indenture, the
Depositary would authorize the Participants holding the relevant beneficial
interests to give such consent or take such action, and such Participants would
authorize beneficial owners holding through such Participants to give such
consent or take such action or would otherwise act upon the instructions of
beneficial owners holding through them.
 
     Principal, premium, if any, and interest payments on the Global Notes
registered in the name of the Depositary or its nominee will be made by the
Trustee to the Depositary or such nominee as the registered owner of the Global
Notes. Under the terms of the Indenture, the Company and the Trustee will treat
the persons in whose names the Global Notes are registered as the sole owner or
holder of the Global Notes for the purpose of receiving payment of principal,
premium, if any, and interest on the Global Notes and for all other purposes
whatsoever. Therefore, neither the Company, the Trustee nor any paying agent has
any direct responsibility or liability for the payment of principal, premium, if
any, or interest on the Global Notes to owners of beneficial interests in the
Global Notes. Neither the Company, the Trustee nor any paying agent will have
any responsibility or liability for any aspect of the records relating to or
payments made on account of beneficial ownership interests in the Notes, or for
maintaining, supervising or reviewing any records relating to such beneficial
ownership interests or for any action or inaction of the Depositary or its
nominee or any Participant.
 
     If (x) the Depositary is at any time unwilling or unable to continue as
Depositary or the Depositary ceases to be a clearing agency registered under the
Exchange Act, (y) the Company executes and delivers to the Trustee an order to
the effect that the Global Notes shall be transferable and exchangeable for
Notes in definitive form or (z) an Event of Default has occurred and is
continuing with respect to the Notes, the Global Notes will be transferable or
exchangeable for Notes in definitive form of like tenor in an equal aggregate
principal amount. Such definitive Notes shall be registered in such name or
names as the Depositary shall instruct the Trustee.
 
SAME-DAY SETTLEMENT AND PAYMENT
 
     Settlement for the Notes will be made by the Underwriter in immediately
available funds. While the Notes are represented by the Global Notes, all
payments of principal and interest will be made by the Company to the Depositary
in immediately available funds.
 
     Secondary trading in long-term notes and debentures of corporate issuers is
generally settled in clearinghouse or next-day funds. In contrast, while the
Notes are represented by the Global Notes, the Notes will trade in the
Depositary's Same-Day Funds Settlement System, and secondary market trading in
the Notes
                                       S-5

<PAGE>   6
will therefore be required by the Depositary to settle in immediately available
funds. No assurance can be given as to the effect, if any, of settlement in
immediately available funds on trading activity in the Notes.
 
                                  UNDERWRITING
 
     Subject to the terms and conditions set forth in the Underwriting
Agreement, the Company has agreed to sell to J.P. Morgan Securities Inc. (the
"Underwriter"), and the Underwriter has agreed to purchase, the $200,000,000
aggregate principal amount of Notes.
 
     Under the terms and conditions of the Underwriting Agreement, the
Underwriter is committed to purchase all of the Notes offered hereby if any are
purchased.
 
     The Underwriter initially proposes to offer the Notes directly to the
public at the public offering price set forth on the cover page of this
Prospectus Supplement and to certain dealers at such price less a concession not
in excess of .40% of the principal amount of the Notes. The Underwriter may
allow, and such dealers may reallow, a concession not in excess of .25% of the
principal amount of the Notes to certain other dealers. After the Notes are
released for sale to the public, the public offering price and such concessions
may be changed by the Underwriter.
 
     The Company does not intend to apply for listing of the Notes on a
securities exchange, but has been advised by the Underwriter that the
Underwriter intends to make a market in the Notes. The Underwriter is not
obligated, however, to make a market in the Notes and may discontinue market
making at any time without notice. No assurance can be given as to the liquidity
of the trading markets for the Notes.
 
     The Company has agreed to indemnify the Underwriter against certain
liabilities including liabilities under the Securities Act of 1933, as amended.
 
     In the ordinary course of their respective businesses, the Underwriter and
its affiliates have engaged and may in the future engage in investment banking
or commercial banking transactions, or both, with the Company and its
affiliates. The Underwriter has agreed to reimburse the Company for $100,000 of
out-of-pocket expenses incurred directly by the Company in connection with this
offering.
 
                                       S-6

<PAGE>   7
 
PROSPECTUS
 
                          THE PROGRESSIVE CORPORATION
                                DEBT SECURITIES
                            ------------------------
     The Progressive Corporation (the "Company") may issue and offer from time
to time in one or more series up to $200,000,000 in aggregate initial public
offering price of its debt securities consisting of debentures, notes or other
unsecured evidences of indebtedness (the "Debt Securities"). The Debt Securities
will rank on a parity with all other current and future unsecured indebtedness
of the Company and prior to subordinated indebtedness, if any. The Debt
Securities may be offered for sale directly to purchasers or through dealers,
underwriters or agents to be designated. The Debt Securities may be offered to
the public on terms determined by market conditions. The Debt Securities may be
sold for U.S. dollars or foreign denominated currency or currency units, and
principal of and any interest on the Debt Securities may likewise be payable in
U.S. dollars or foreign denominated currency or currency units. The currency or
currency units for which the Debt Securities may be purchased and the currency
or currency units in which principal of and interest on the Debt Securities will
be payable will be specifically designated in one or more supplements to this
Prospectus (each a "Prospectus Supplement").
 
     The specific designation, aggregate principal amount, authorized
denominations, purchase price, maturity, any premium, any interest rate (which
may be fixed or variable) or manner of calculation thereof, any interest payment
dates, any optional or mandatory redemption terms, any sinking fund provisions,
listing on a securities exchange, and any other specific terms relating to any
series of Debt Securities, and the name of each dealer, underwriter or agent, if
any, involved in the sale of any series of Debt Securities and any compensation
to any such dealer, underwriter or agent, will be set forth in a Prospectus
Supplement.
 
     This Prospectus may not be used to consummate sales of Debt Securities
unless accompanied by a Prospectus Supplement.
                            ------------------------
THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES
 AND EXCHANGE COMMISSION, ANY STATE SECURITIES COMMISSION OR THE NORTH
   CAROLINA INSURANCE COMMISSIONER NOR HAS THE SECURITIES AND EXCHANGE
    COMMISSION, ANY STATE SECURITIES COMMISSION OR SUCH COMMISSIONER
     PASSED UPON THE ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY
      REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.
                            ------------------------
     The Debt Securities may be sold directly to purchasers or to dealers or
underwriters or through agents to be designated from time to time, subject to
the approval of certain legal matters by counsel for such purchasers, dealers,
underwriters or agents. Net proceeds to the Company will be the purchase price
in the case of a purchaser or dealer, the public offering price less
underwriting discount in the case of an underwriter or the purchase price less
commission in the case of an agent less, in each case, other attributable
issuance and distribution expenses. See "Plan of Distribution" for possible
indemnification arrangements for dealers, underwriters and agents.
 
                 The date of this Prospectus is January 5, 1994

<PAGE>   8
 
     NO PERSON HAS BEEN AUTHORIZED TO GIVE ANY INFORMATION OR TO MAKE ANY
REPRESENTATIONS NOT CONTAINED OR INCORPORATED BY REFERENCE IN THIS PROSPECTUS IN
CONNECTION WITH THE OFFERING MADE HEREBY, AND IF GIVEN OR MADE, SUCH INFORMATION
OR REPRESENTATIONS MUST NOT BE RELIED UPON. THIS PROSPECTUS DOES NOT CONSTITUTE
AN OFFER TO SELL OR A SOLICITATION OF AN OFFER TO BUY ANY SECURITIES OTHER THAN
THE REGISTERED SECURITIES TO WHICH IT RELATES OR AN OFFER TO SELL OR A
SOLICITATION OF AN OFFER TO BUY ANY SECURITIES IN ANY JURISDICTION IN WHICH SUCH
OFFER OR SOLICITATION MAY NOT BE LEGALLY MADE. THE DELIVERY OF THIS PROSPECTUS
AT ANY TIME DOES NOT IMPLY THAT THE INFORMATION HEREIN IS CORRECT AS OF ANY TIME
SUBSEQUENT TO THE DATE HEREOF.
 
                             AVAILABLE INFORMATION
 
     The Company is subject to the informational requirements of the Securities
Exchange Act of 1934, as amended (the "Exchange Act"), and in accordance
therewith files reports, proxy statements and other information with the
Securities and Exchange Commission (the "Commission"). Such reports, proxy
statements and other information can be inspected and copied at the public
reference facilities maintained by the Commission at Judiciary Plaza, 450 Fifth
Street N.W., Room 1024, Washington, D.C. 20549, and at the following regional
offices of the Commission: 7 World Trade Center, New York, New York 10048, and
The Citicorp Center, 500 West Madison Street, Suite 1400, Chicago, Illinois
60621-2511. Copies of such material can be obtained at prescribed rates from the
Public Reference Section of the Commission, 450 Fifth Street N.W., Washington,
D.C. 20549. Reports, proxy statements and other information concerning the
Company may also be inspected at the New York Stock Exchange, 20 Broad Street,
New York, New York 10005.
 
     This Prospectus constitutes a part of a Registration Statement filed by the
Company with the Commission under the Securities Act of 1933, as amended (the
"Securities Act"). This Prospectus omits certain of the information contained in
the Registration Statement, and reference is hereby made to the Registration
Statement and related exhibits for further information with respect to the
Company and the securities offered hereby. Statements contained herein
concerning the provisions of any document are not necessarily complete and, in
each instance, reference is made to the copy of such document filed as an
exhibit to the Registration Statement or otherwise filed with the Commission.
Each such statement is qualified in its entirety by such reference. These
documents may be inspected without charge at the office of the Commission at
Judiciary Plaza, 450 Fifth Street N.W., Washington, D.C. 20549, and copies may
be obtained at fees and charges prescribed by the Commission.
 
                INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE
 
     The following documents filed by the Company with the Commission pursuant
to the Exchange Act are incorporated herein by reference:
 
     (1) The Company's Annual Report on Form 10-K for the year ended December
         31, 1992, as amended by the Company's Form 10-K/A-No. 1 filed with the
         Commission on July 7, 1993;
 
     (2) The Company's Quarterly Reports on Form 10-Q for the quarters ended
         March 31, 1993, June 30, 1993 and September 30, 1993; and
 
     (3) The Company's Current Reports on Form 8-K dated July 14, 1993 and
         November 12, 1993.
 
     All reports and other documents filed by the Company pursuant to Section
13(a), 13(c), 14 or 15(d) of the Exchange Act after the date of this Prospectus
and prior to the termination of this offering are hereby incorporated by
reference into this Prospectus and shall be deemed a part hereof from the
respective dates of filing of such reports and documents. Any statement
contained in a document incorporated or deemed to be incorporated herein by
reference shall be deemed to be modified or superseded for purposes of this
Prospectus to the extent that a statement contained herein or in any other
subsequently filed document which also is or is deemed to be incorporated by
reference in this Prospectus modifies or supersedes such statement. Any such
statement so modified or superseded shall not be deemed, except as so modified
or superseded, to constitute a part of this Prospectus.
 
     The Company will furnish without charge to each person to whom a Prospectus
is delivered, upon written or oral request, a copy of any or all of the
foregoing documents incorporated herein by reference (other than certain
exhibits). Requests for such documents should be directed to Jeffrey W. Basch,
Chief Accounting Officer, The Progressive Corporation, at 6300 Wilson Mills
Road, Mayfield Village, Ohio 44143 or by telephone at (216) 461-5000.
 
                                        2

<PAGE>   9
 
                                  THE COMPANY
 
     The Company is an insurance holding company which owns 52 operating
subsidiaries and has one mutual insurance company affiliate. Progressive
Casualty Insurance Company is the principal operating subsidiary. The insurance
company subsidiaries write private passenger automobile and other specialty
property-casualty and credit-related insurance and provide related services
throughout the United States and in Canada. Of the 250 largest domestic
property-casualty insurance company groups, the Progressive insurance group is
ranked 36th in size based on 1992 net premiums written, as reported in the July
1993 issue of Best's Review -- Property/Casualty Insurance Edition.
 
     The Company's core business, which accounted for 93% of the Company's total
net premiums written in 1992, is to write primarily nonstandard private
passenger automobile and small commercial vehicle insurance, as well as
insurance for motorcycles, motor homes and mobile homes. Nonstandard automobile
programs provide insurance for private passenger automobile risks that have been
rejected or cancelled by other companies. The Progressive insurance group is a
major participant in the nonstandard automobile segment of the property-casualty
insurance industry.
 
     The Company's diversified businesses, which accounted for 7% of total net
premiums written in 1992, offer lender's collateral protection insurance, bank
directors' and officers' liability insurance, financial institution bonds and
other insurance products to customers in the financial services industry. The
diversified businesses also provide insurance, on a heavily reinsured basis, and
related services to a select group of regional customers in the motor
transportation industry, involuntary auto insurance plan management as a
Commercial Auto Insurance Plan servicing carrier in 27 states, and third party
risk management and claims service to a variety of commercial accounts.
 
     Prospective purchasers of Debt Securities should be aware that ownership of
Debt Securities may involve certain risks. For example, the Company encounters
vigorous competition in the automobile insurance and other property-casualty
markets in which it operates. See the "Competitive Factors" discussion contained
in Item 1 of the Company's 1992 Annual Report on Form 10-K, as amended. In
addition, the Company's business is subject to extensive state regulation. See
the "Insurance Regulation" discussion contained in Item 1 of the Company's 1992
Annual Report on Form 10-K, as amended.
 
     The Company's principal executive office is located at 6300 Wilson Mills
Road, Mayfield Village, Ohio 44143, and its telephone number is (216) 461-5000.
 
                                USE OF PROCEEDS
 
     Except as otherwise provided in an applicable Prospectus Supplement, the
net proceeds from the sale of the Debt Securities will be used by the Company
for general corporate purposes. The net proceeds will be added to the investment
portfolios of the Company or its subsidiaries and may be used, in whole or in
part, to support premium growth. Such proceeds will be invested in the same
kinds of securities, and in approximately the same proportion, as those
currently held in such investment portfolios. A discussion of the nature of such
securities, and the risks relating thereto, is set forth in the "Investments"
section of Management's Discussion and Analysis of Financial Condition and
Results of Operations contained in the Company's 1992 Annual Report on Form
10-K, as amended.
 
                                        3

<PAGE>   10
 
                  SELECTED CONSOLIDATED FINANCIAL INFORMATION
 
     The following selected consolidated financial information concerning the
Company and its subsidiaries for the five years ended December 31, 1992, and for
the nine months ended September 30, 1993 and 1992, should be read in conjunction
with the more detailed information and financial statements incorporated by
reference herein and available as described under "Available Information" and
"Incorporation of Certain Documents by Reference." The information for the
interim periods is unaudited but, in the opinion of management, includes all
adjustments (consisting only of normal recurring accruals) necessary for a fair
presentation of such information. The interim results of operations may not be
indicative of the results for the full year. All per share amounts have been
adjusted to reflect the 3-for-1 stock split of the Common Shares effected on
December 8, 1992.
 

<TABLE>
<CAPTION>
                                              NINE MONTHS ENDED
                                                SEPTEMBER 30,                          YEARS ENDED DECEMBER 31,
                                            -------------------    ------------------------------------------------------------
                                              1993        1992        1992        1991         1990         1989         1988
                                            --------    --------    --------    --------     --------     --------     --------
                                                               (DOLLARS IN MILLIONS EXCEPT PER SHARE DATA)
<S>                                         <C>         <C>         <C>         <C>          <C>          <C>          <C>
Direct premiums written:                               
  Personal lines..........................  $1,155.8    $  902.7    $1,214.6    $1,047.4     $  876.0     $  800.1     $  817.0
  Commercial lines........................     303.0       322.7       422.2       489.4        482.8        487.0        521.0
                                            --------    --------    --------    --------     --------     --------     --------
Total direct premiums written.............  $1,458.8    $1,225.4    $1,636.8    $1,536.8     $1,358.8     $1,287.1     $1,338.0
                                            --------    --------    --------    --------     --------     --------     --------
                                            --------    --------    --------    --------     --------     --------     --------
Net premiums written(1)(2)................  $1,357.2    $1,079.4    $1,451.2    $1,324.6     $1,196.3     $1,160.3     $1,275.0
                                            --------    --------    --------    --------     --------     --------     --------
                                            --------    --------    --------    --------     --------     --------     --------
Revenues:                                                                     
  Premiums earned(2)......................  $1,215.4    $1,045.1    $1,426.1    $1,286.9     $1,191.2     $1,196.5     $1,215.4
  Investment income(3)....................      98.0       103.4       139.0       144.8        152.5        168.7        109.9
  Net realized gains (losses) on security                                     
    sales(4)..............................      98.2        11.3        14.5         7.4        (12.8)         (.6)        18.6
  Service revenues........................      33.5        40.8        53.3        54.0         45.3         28.1         11.9
  Proposition 103 reserve reduction(5)....        --       106.0       106.0          --           --           --           --
                                            --------    --------    --------    --------     --------     --------     --------
Total revenues............................   1,445.1     1,306.6     1,738.9     1,493.1      1,376.2      1,392.7      1,355.8
                                            --------    --------    --------    --------     --------     --------     --------
Expenses:                                                                     
  Losses and loss adjustment expenses.....     747.3       686.4       930.9       858.0        762.9        799.3        752.0
  Policy acquisition costs................     229.1       234.6       304.1       313.7        292.7        296.7        321.3
  Other underwriting expenses.............     102.8       102.5       141.5       162.1        123.7        114.9        106.6
  Investment expenses.....................       7.2        14.2        17.0        22.5         19.2         20.0         11.1
  Service and other expenses..............      29.1        38.8        57.6        56.1         41.1         26.4         16.8
  Interest expense........................      28.4        33.9        44.5        47.8         48.5         49.3         16.0
  Non-recurring transactions(6)...........        --        54.6        64.6          --           --           --           --
                                            --------    --------    --------    --------     --------     --------     --------
Total expenses............................   1,143.9     1,165.0     1,560.2     1,460.2      1,288.1      1,306.6      1,223.8
                                            --------    --------    --------    --------     --------     --------     --------
Income before Federal income taxes and                                        
  cumulative effect of accounting change..     301.2       141.6       178.7        32.9         88.1         86.1        132.0
Provision (benefit) for Federal income                                        
  taxes...................................      87.3        34.9        39.1          --         (5.3)         8.1         23.9
                                            --------    --------    --------    --------     --------     --------     --------
Income before cumulative effect of                                            
  accounting change.......................     213.9       106.7       139.6        32.9         93.4         78.0        108.1
Cumulative effect of accounting                                               
  change(7)...............................        --        14.2        14.2          --           --           --           --
                                            --------    --------    --------    --------     --------     --------     --------
Net income................................  $  213.9    $  120.9    $  153.8    $   32.9     $   93.4     $   78.0     $  108.1
                                            --------    --------    --------    --------     --------     --------     --------
                                            --------    --------    --------    --------     --------     --------     --------
Per Common Share(8):                                                          
  Income before cumulative effect of                                          
    accounting change:                                                        
    Primary...............................  $   2.92    $   1.60    $   2.09    $    .41     $   1.28     $    .98     $   1.29
    Fully diluted.........................      2.91        1.42        1.85         .41         1.19          .94         1.23
  Net income:                                                                 
    Primary...............................      2.92        1.82        2.32         .41         1.28          .98         1.29
    Fully diluted.........................      2.91        1.61        2.05         .41         1.19          .94         1.23
Ratio of earnings to fixed charges(9).....     10.2x        4.8x        4.6x        1.6x         2.6x         2.6x         7.3x
Ratio of earnings to combined fixed                                           
  charges and preferred share dividend                                        
  requirements(9).........................      7.8x        3.8x        3.7x        1.5x           --           --           --
GAAP operating ratios:                                                        
  Loss and loss adjustment expense ratio..      61.5%       65.7%       65.3%       66.7%        64.0%        66.8%        61.9%
  Underwriting expense ratio..............      27.3%       32.3%       31.2%       37.0%        35.0%        34.4%        35.2%
                                            --------    --------    --------    --------     --------     --------     --------
  Combined ratio..........................      88.8%       98.0%       96.5%      103.7%        99.0%       101.2%        97.1%
                                            --------    --------    --------    --------     --------     --------     --------
                                            --------    --------    --------    --------     --------     --------     --------
Statutory operating ratios:                                                   
  Loss and loss adjustment expense ratio..      62.5%       68.6%       68.3%       65.7%        62.1%        65.9%        62.9%
  Underwriting expense ratio..............      25.0%       30.6%       29.8%       33.5%        31.1%        31.4%        33.2%
                                            --------    --------    --------    --------     --------     --------     --------
  Combined ratio(10)......................      87.5%       99.2%       98.1%       99.2%        93.2%        97.3%        96.1%
                                            --------    --------    --------    --------     --------     --------     --------
                                            --------    --------    --------    --------     --------     --------     --------
</TABLE>
                                                                      
                                                                              

<TABLE>                                                            
<CAPTION>                                
                                                SEPTEMBER 30,                                 DECEMBER 31,
                                            --------------------    -----------------------------------------------------------
                                              1993        1992        1992        1991         1990         1989         1988
                                            --------    --------    --------    --------     --------     --------     --------
                                                                         (DOLLARS IN MILLIONS)
<S>                                         <C>         <C>         <C>         <C>          <C>          <C>          <C>
Total assets..............................  $3,593.9    $3,020.8    $3,005.1    $2,979.1     $2,705.3     $2,643.7     $2,316.3
Funded debt...............................     568.6       643.6       568.5       644.0        644.4        645.9        479.2
Shareholders' equity......................     953.5       511.9       629.0       465.7        408.5        435.2        417.2
</TABLE>
                                 
                                         
                                                        (footnotes on next page)
 
                                        4

<PAGE>   11
 
(footnotes from previous page)
 
 (1) Total direct premiums written net of reinsurance.
 
 (2) From 1989 until the second quarter of 1992, the Company maintained a
     reserve for potential premium refunds under rollback and refund provisions
     of California's Proposition 103, reducing net premiums written and premiums
     earned. Net premiums written and premiums earned were reduced $10.2 million
     for the nine months ended September 30, 1992, as well as the twelve months
     ended December 31, 1992, and $49.7 million, $54.4 million and $39.0 million
     for the years ended December 31, 1991, 1990 and 1989, respectively. As a
     result, net income for the nine months ended September 30, 1992, as well as
     the twelve months ended December 31, 1992, was reduced $6.7 million, or
     $.09 per share. Net income was reduced $32.8 million, or $.49 per share,
     $35.9 million, or $.44 per share, and $25.7 million, or $.29 per share, for
     the years ended December 31, 1991, 1990 and 1989, respectively.
 
 (3) Investment income includes dividends and interest.
 
 (4) Increase in net realized gains on security sales for the nine months ended
     September 30, 1993, is primarily due to the sale of certain equity
     securities held in the Company's investment portfolio, which accounted for
     $74.3 million of the total gain.
 
 (5) On June 12, 1992, the Company reached agreement with the California
     Department of Insurance to refund approximately $50 million of premiums
     (including interest) on business written between November 8, 1988 and
     November 7, 1989 to approximately 260,000 policyholders, thereby settling
     all rollback and refund exposure since Proposition 103 was adopted in
     November 1988. As a result, the Company's Proposition 103 premium refund
     and rollback reserve was reduced by $106.0 million for both the nine months
     ended September 30, 1992 and the year ended December 31, 1992. As a result,
     net income was increased $70.0 million, or $.97 per share, for both the
     nine months ended September 30, 1992 and the year ended December 31, 1992.
 
 (6) Non-recurring transactions include (a) a $10 million payment to Alfred
     Lerner made in December 1992, pursuant to an agreement (the "November
     Agreement") in which he agreed, among other matters, to convert $75 million
     in principal amount of the Company's Floating Rate Convertible Subordinated
     Debentures due 2008 (the "Convertible Debentures") into 9,000,000 Common
     Shares and to terminate his employment agreement with the Company, and (b)
     a one-time charge, including an additional incentive fee for the period
     ended June 30, 1992, in the amount of $54.6 million paid by the Company to
     Progressive Partners Limited Partnership ("Progressive Partners") for
     terminating the Company's Investment Management Agreement with Progressive
     Partners. In December 1992, Mr. Lerner sold in an underwritten public
     offering 5,175,000 of the Common Shares received upon the conversion of the
     Convertible Debentures and since that date has sold the balance of such
     Common Shares. See paragraphs six and seven of the "Financial Condition"
     section in Management's Discussion and Analysis of Financial Condition and
     Results of Operations incorporated by reference from the Company's Annual
     Report on Form 10-K for the year ended December 31, 1992, as amended.
 
 (7) Effective January 1, 1992, the Company adopted Statement of Financial
     Accounting Standards (SFAS) 109, "Accounting for Income Taxes," which
     changes the method of accounting for income taxes. Under SFAS 109, the
     Company is able to demonstrate that the benefit of deferred tax assets is
     fully realizable. The cumulative effect of adopting SFAS 109 increased net
     income $14.2 million, or $.20 per share, for the year ended December 31,
     1992; the deferred tax asset writedown was taken in 1991, as required under
     SFAS 96.
 
 (8) Net income is reduced by Preferred Share dividends earned during the period
     for both the primary and fully diluted earnings per share calculations.
     Primary earnings per share are computed using the weighted average number
     of Common Shares and equivalents, including stock options, outstanding
     during the period. Prior to December 16, 1992 (the date of conversion of
     the Convertible Debentures), fully diluted earnings per share assumed the
     conversion of the Convertible Debentures and the effects of related
     interest expense and income taxes. See Note 6 above.
 
 (9) Earnings consist of income before Federal income taxes and cumulative
     effect of accounting change ($14.2 million in 1992) and before fixed
     charges. Fixed charges consist of interest and amortization on indebtedness
     and the portion of rents representative of the interest factor. Combined
     fixed charges and preferred share dividend requirements consist of fixed
     charges and pretax earnings required to pay preferred share dividends.
 
(10) Insurance industry combined ratios, presented on a statutory basis and
     obtained from A.M. Best Company Inc.'s "Best's Insurance Management Reports
     -- P/C Supplement" dated March 25, 1993, are set forth below:
 

<TABLE>
<CAPTION>
             YEARS ENDED DECEMBER 31,
- ---------------------------------------------------
 1992       1991       1990       1989       1988
- -------    -------    -------    -------    -------
<S>        <C>        <C>        <C>        <C>
115.7%     108.8%     109.5%     109.2%     105.5%
</TABLE>

 
                                        5

<PAGE>   12
 
                         DESCRIPTION OF DEBT SECURITIES
 
     The Company may offer under this Prospectus and one or more Prospectus
Supplements Debt Securities not exceeding $200,000,000 in aggregate initial
public offering price. The following description of the terms of the Debt
Securities sets forth certain general terms and provisions of the Debt
Securities which may be offered under a Prospectus Supplement. The particular
terms and provisions of the Debt Securities offered by any Prospectus Supplement
and the extent, if any, to which such general provisions may apply to the Debt
Securities so offered will be described in the Prospectus Supplement relating to
such Debt Securities.
 
     The Debt Securities offered hereby will represent unsecured general
obligations of the Company and will rank on a parity with all other existing and
future unsecured and unsubordinated indebtedness of the Company and prior to
subordinated indebtedness, if any. The Debt Securities are to be issued under an
Indenture dated as of September 15, 1993 (the "Indenture") entered into between
the Company and The First National Bank of Boston, as Trustee (the "Trustee").
Debt Securities may be issued in one or more series under the Indenture. The
Indenture does not limit the amount of Debt Securities or any other debt which
may be incurred by the Company. In addition, the provisions of the Indenture do
not afford holders of the Debt Securities protection in the event of a highly
leveraged transaction, reorganization, restructuring, merger or similar
transaction involving the Company that may adversely affect holders of the Debt
Securities. The following summaries of certain provisions of the Indenture do
not purport to be complete and are subject to, and are qualified in their
entirety by reference to, all provisions of the Indenture, which is an exhibit
to the Registration Statement of which this Prospectus is a part. Certain
capitalized terms used herein are defined in the Indenture. References are to
sections or articles of the Indenture.
 
GENERAL
 
     The Indenture does not limit the amount of Debt Securities which may be
issued thereunder and provides that Debt Securities may be issued in series
thereunder up to the aggregate principal amount which may be authorized from
time to time by the Company. The Debt Securities may be denominated and payable
in U.S. dollars, foreign currencies or units based on or relating to U.S. or
foreign currencies. Debt Securities may be offered to the public on terms
determined by market conditions at the time of sale.
 
     Reference is made to the appropriate Prospectus Supplement for the
following terms of each series of Debt Securities in respect of which this
Prospectus is being delivered: (1) the designation, aggregate principal amount
and authorized denominations of such Debt Securities; (2) the purchase price of
such Debt Securities (expressed as a percentage of the principal amount
thereof); (3) the date on which such Debt Securities will mature; (4) the rate
or rates per annum at which such Debt Securities will bear interest, if any, or
the method by which such rate or rates will be determined; (5) the coin or
currency or units based on or relating to currencies in which Debt Securities
may be purchased and in which payment of principal and interest will be made;
(6) the periods for which and the dates on which such interest, if any, will be
payable; (7) the place or places where the principal of and interest, if any, on
such Debt Securities will be payable; (8) the terms of any mandatory or optional
redemption (including any sinking fund); (9) whether such Debt Securities will
be issuable in registered form or bearer form (with or without coupons) or both,
and, if Debt Securities in bearer form will be issued, restrictions applicable
to the exchange of one form for another and to the offer, sale and delivery of
Debt Securities in bearer form; (10) whether, and under what circumstances, the
Company will pay additional amounts on such Debt Securities held by a person who
is not a U.S. person (as defined in an appropriate Prospectus Supplement) in
respect of any tax, assessment or governmental charge withheld or deducted, and
if so, whether the Company will have the option to redeem such Debt Securities
rather than pay such additional amounts; and (11) any other specific terms of
such series. If a Prospectus Supplement specifies that Debt Securities are
denominated in a currency other than U.S. dollars or U.S. currency units, such
Prospectus Supplement shall also specify the denomination in which such Debt
Securities will be issued and the coin or currency or currency unit in which the
principal of and premium, if any, and interest on such Debt Securities will be
payable, which may be U.S. dollars based upon the exchange rate for such other
currency or currency unit existing on or about the time a payment is due.
 
     Debt Securities may be presented for exchange and registered Debt
Securities may be presented for transfer in the manner, at the places and
subject to the restrictions set forth in the Indenture. Such services
 
                                        6

<PAGE>   13
 
will be provided without charge, other than any tax or other governmental charge
payable in connection therewith, but subject to the limitations provided in the
Indenture. Debt Securities in bearer form and the coupons, if any, pertaining
thereto will be transferable by delivery.
 
     The Debt Securities will be unsecured. The Debt Securities will rank on a
parity with all other existing and future unsecured and unsubordinated
indebtedness of the Company and prior to subordinated indebtedness, if any.
Because the Company is a holding company, however, its rights and the rights of
its creditors to participate in the assets of any subsidiary upon the latter's
liquidation or recapitalization (and thus the ability of holders of the Debt
Securities to benefit as creditors of the Company in such liquidation or
recapitalization) will be subject to the prior claims of the subsidiary's
creditors, except to the extent that the Company may itself be a creditor with
recognized claims against the subsidiary, other than as a holder of the
subsidiary's outstanding shares of capital stock.
 
     In addition, insurance statutes in many states impose limitations on the
ability of regulated insurance companies to pay dividends and transfer assets to
their affiliates. Such statutes may require prior approval for the payment of
dividends by the Company's regulated insurance company subsidiaries to the
Company or its affiliates. Since a significant source of the Company's
internally generated cash flow is dividends paid to it by its subsidiaries, the
Company's ability to meet its obligations (including the obligation to pay
principal of and premium, if any, and interest on the Debt Securities) may be
affected by any such limitations or prior approval requirements.
 
     Some of the Debt Securities may be issued as original issue discount Debt
Securities (bearing no interest or interest at a rate which at the time of
issuance is below market rates), to be sold at a substantial discount below
their stated principal amount. Federal income tax, accounting and other special
considerations applicable to any such original issue discount Debt Securities
will be described in a Prospectus Supplement relating thereto.
 
GLOBAL SECURITIES
 
     The Debt Securities may be issued in the form of one or more global
securities (a "Global Security") that will be deposited with a depositary (a
"Depositary") or with a nominee for a Depositary identified in an appropriate
Prospectus Supplement and registered in the name of the Depositary or a nominee
thereof. In such case, one or more Global Securities will be issued in a
denomination or aggregate denominations equal to the portion of the aggregate
principal amount of outstanding Debt Securities to be represented by such Global
Security or Securities. Unless and until it is exchanged in whole or in part for
Debt Securities in definitive registered form, a Global Security may not be
transferred, except as a whole by the Depositary for such Global Security to a
nominee of such Depositary or by a nominee of such Depositary to such Depositary
or another nominee of such Depositary or by such Depositary or any such nominee
to a successor of such Depositary or a nominee of such successor.
 
     The specific terms of the depositary arrangement with respect to any Debt
Securities to be represented by a Global Security will be described in a
Prospectus Supplement relating thereto.
 
EVENTS OF DEFAULT, WAIVER AND NOTICE
 
     As to any series of Debt Securities, an Event of Default is defined in the
Indenture as (a) default for 30 days in payment of any interest on the Debt
Securities of such series; (b) default in payment of principal of or premium, if
any, on the Debt Securities of such series when due either at maturity, upon
redemption, by declaration or otherwise; (c) default in the payment of a sinking
fund installment, if any, on the Debt Securities of such series; (d) default by
the Company in the performance of any other covenant or warranty contained in
the Indenture for the benefit of such series which shall not have been remedied
for a period of 60 days after notice given as specified in the Indenture; and
(e) certain events of bankruptcy, insolvency and reorganization of the Company.
(Section 5.1 of the Indenture.) An Event of Default with respect to a particular
series of Debt Securities issued under the Indenture does not necessarily
constitute an Event of Default with respect to any other series of Debt
Securities issued thereunder. The Indenture provides that the Trustee may
withhold notice to the holders of Debt Securities of any series of any default
(except in payment of principal of, or premium, if any, or interest on such Debt
Securities) if the Trustee considers it in the
 
                                        7

<PAGE>   14
 
interest of the holders of Debt Securities of such series to do so; provided,
however, that in the case of a default of the character specified in clause (d)
above, no such notice to holders of Debt Securities of such series shall be
given until at least 30 days after the occurrence thereof. (Section 5.11 of the
Indenture.)
 
     The Indenture provides that (1) if an Event of Default described in clause
(a), (b), (c) or (d) above with respect to a particular series of Debt
Securities shall have occurred and be continuing, either the Trustee or the
holders of at least 25% in principal amount of the Debt Securities of such
series then outstanding may declare the entire principal (or, in the case of
original issue discount Debt Securities, the portion thereof specified in the
terms thereof) of all outstanding Debt Securities of such series and the
interest accrued thereon, if any, to be due and payable immediately and (2) if
an Event of Default described in clause (e) above shall have occurred and be
continuing, either the Trustee or the holders of at least 25% in principal
amount of all Debt Securities then outstanding thereunder (voting as one class)
may declare the entire principal (or, in the case of original issue discount
Debt Securities, the portion thereof specified in the terms thereof) of all Debt
Securities then outstanding thereunder and the interest accrued thereon, if any,
to be due and payable immediately, but upon certain conditions such declarations
may be annulled and past defaults (except for defaults in the payment of
principal of or premium, if any, or interest on such Debt Securities) may be
waived by the holders of a majority in principal amount of the Debt Securities
of such series (or of all series thereunder, as the case may be) then
outstanding. (Sections 5.1 and 5.10 of the Indenture.)
 
     The Indenture provides that holders of a majority in principal amount of
the outstanding Debt Securities of each series affected (with each series voting
as a separate class) shall have the right to direct the time, method and place
of conducting any proceeding for any remedy available to the Trustee under the
Indenture with respect to Debt Securities of such series, subject to certain
limitations specified in the Indenture, provided that the holders of Debt
Securities shall have offered to the Trustee reasonable security or indemnity
against expenses and liabilities. (Sections 5.9 and 6.2(d) of the Indenture.)
The Indenture requires the annual delivery by the Company to the Trustee of a
written statement as to the absence of certain defaults under the Indenture.
(Section 3.5 of the Indenture.) Whenever the Indenture provides for an action
by, or the determination of any of the rights of, or any distribution to,
holders of Debt Securities denominated in U.S. dollars and in any other currency
or currency unit, in the absence of any provision to the contrary in the form of
Debt Security of any particular series, any amount in respect of any Debt
Security denominated in a currency or currency unit other than U.S. dollars
shall be treated for any such action or distribution as the amount of U.S.
dollars that could be obtained for such amount on such reasonable basis of
exchange and as of such date as the Company reasonably specifies to the Trustee
or in the absence of such specification, as the Trustee may determine. (Section
11.11 of the Indenture.) Under the terms of the Indenture, the holders of a
majority in aggregate principal amount of all series of the Debt Securities to
be affected thereby at the time outstanding may waive compliance with certain
covenants contained in the Indenture. (Section 5.10 of the Indenture.)
 
MODIFICATION OF THE INDENTURE
 
     The Indenture contains provisions permitting the Company and the Trustee,
with the consent of the holders of not less than 66 2/3% in aggregate principal
amount of the Debt Securities of all series affected by such modification at the
time outstanding (voting as one class), to modify the Indenture or any
supplemental indenture or the rights of the holders of such Debt Securities;
provided that no such modification shall (i) extend the final maturity of any
Debt Security, or reduce the principal amount thereof, or reduce the rate or
extend the time of payment of interest thereon, or change the currency or
currency unit of payment thereof, or change the method by which amounts of
payments of principal or interest thereon are determined, or reduce the portion
of the principal amount of an original issue discount Debt Security due and
payable upon acceleration of the maturity thereof or the portion of the
principal amount thereof provable in bankruptcy, or reduce any amount payable
upon redemption of any Debt Security, or impair or affect the right of a holder
to institute suit for the payment thereof or, if the Debt Securities provide
therefor, any right of repayment at the option of the holder of a Debt Security,
without the consent of the holders of each Debt Security so affected or (ii)
reduce the aforesaid percentage of Debt Securities of any series, the consent of
the holders of which is required for any such modification, without the consent
of the holder of each Debt Security so affected. (Section 8.2 of the Indenture.)
The Indenture also provides that the Company and the Trustee may from time to
time execute supplemental indentures. (Section 8.1 of the Indenture.)
 
                                        8

<PAGE>   15
 
CONSOLIDATIONS, MERGERS, AND SALES OF ASSETS
 
     The Company may not merge or consolidate with any other corporation or sell
or convey all or substantially all of its assets to any Person, unless either
the Company shall be the continuing corporation or the successor corporation
shall be a corporation organized under the laws of the United States or any
state thereof and shall expressly assume the payment of the principal of and
interest on the Debt Securities and the performance and observance of all the
covenants and conditions of the Indenture binding upon the Company, and the
Company or such successor corporation shall not, immediately after such merger
or consolidation, or such sale or conveyance, be in default in the performance
of any such covenant or condition. (Article Nine of the Indenture.) No
quantitative or other established meaning has been given to the phrase "all or
substantially all" by courts which have interpreted this phrase in various
contexts. In interpreting this phrase, courts make a subjective determination as
to the portion of assets sold or conveyed, considering such factors as the value
of the assets sold or conveyed and the proportion of an entity's income derived
from the assets sold or conveyed. Accordingly, there may be uncertainty as to
whether holders of the Debt Securities can determine whether the Company has
sold or conveyed all or substantially all of its assets and exercise any
remedies such holders may have upon the occurrence of any such transaction.
 
DEFEASANCE
 
     The Indenture provides that, unless the terms of any series of Debt
Securities provide otherwise, the Company will be discharged from obligations in
respect of the outstanding Debt Securities of any series and the provisions of
the Indenture with respect thereto (excluding certain obligations, such as
obligations to register the transfer or exchange of such outstanding Debt
Securities, to replace stolen, lost or mutilated certificates or coupons, and to
hold moneys for payment in trust), upon the irrevocable deposit, in trust, of
cash or U.S. Government obligations (as defined in the Indenture) which, through
the payment of interest and principal thereof in accordance with their terms,
will provide cash in an amount sufficient to pay the principal of and premium,
if any, and interest on and mandatory sinking fund payments, if any, in respect
of outstanding Debt Securities of such series on the stated dates such payments
are due in accordance with the terms of the Indenture and such outstanding Debt
Securities, provided that the Company has received an opinion of counsel to the
effect that such a discharge will not be deemed, or result in, a taxable event
with respect to holders of such outstanding Debt Securities and that certain
other conditions are met. (Section 10.1(B) of the Indenture.)
 
SATISFACTION AND DISCHARGE
 
     The Indenture will cease to be of further effect and the Trustee, on demand
of and at the expense of the Company, shall execute appropriate instruments
acknowledging the satisfaction and discharge of the Indenture upon compliance
with certain enumerated conditions, including the Company having paid all sums
payable by the Company under the Indenture, when either (a) the Company shall
have delivered to the Trustee for cancellation all Debt Securities theretofore
authenticated or (b) all Debt Securities not theretofore delivered to the
Trustee for cancellation shall have become due and payable or are by their terms
to become due and payable within one year. (Section 10.1(A) of the Indenture.)
 
GOVERNING LAW
 
     The Debt Securities and the Indenture will be governed by the laws of the
State of New York. (Section 11.8 of the Indenture.)
 
CONCERNING THE TRUSTEE
 
     The First National Bank of Boston is the Trustee under the Indenture. The
First National Bank of Boston has made and may from time to time make loans to
the Company in the normal course of business. The First National Bank of Boston
also serves as trustee for the Company's outstanding 10% Notes due December 15,
2000 and the Company's outstanding 7% Notes due October 1, 2013.
 
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<PAGE>   16
 
                              PLAN OF DISTRIBUTION
 
     The Company may sell the Debt Securities being offered hereby (i) through
agents, (ii) through underwriters, (iii) through dealers or (iv) directly to one
or more purchasers. The Prospectus Supplement with respect to a particular
offering of Debt Securities will set forth the terms of the offering of such
Debt Securities, including the name or names of the specific agents, dealers or
underwriters (including managing underwriters, if any), the purchase price and
the proceeds to the Company from such sales, any underwriting discounts, agency
fees or commissions and other items constituting compensation to the
underwriters, agents or dealers, initial public offering price, any discounts or
concessions to be allowed or reallowed or paid to dealers, the securities
exchange, if any, on which such Debt Securities may be listed, and the place and
time of delivery of the Debt Securities offered.
 
     Debt Securities may be offered and sold through agents designated by the
Company from time to time. Unless otherwise indicated in the applicable
Prospectus Supplement, any such agent will be acting on a best efforts basis for
the period of its appointment. Any such agent may be deemed to be an
underwriter, as that term is defined in the Securities Act, of any Debt
Securities so offered and sold. Agents may be entitled under agreements which
may be entered into with the Company to indemnification by the Company against
certain liabilities, including liabilities under the Securities Act, and may be
customers of, engage in transactions with, or perform services for, the Company
in the ordinary course of business.
 
     If an underwriter or underwriters are utilized in the sale of any Debt
Securities, the Company will execute an underwriting agreement with such
underwriter or underwriters at the time an agreement for such sale is reached.
Such underwriter or underwriters will acquire Debt Securities for their own
account and may resell such Debt Securities from time to time in one or more
transactions, including negotiated transactions, at fixed public offering prices
or at varying prices determined at the time of sale. Debt Securities may be
offered to the public either through underwriting syndicates represented by
managing underwriters, or by underwriters without a syndicate. The underwriters
may be entitled, under the relevant underwriting agreement, to indemnification
by the Company against certain liabilities, including liabilities under the
Securities Act. If any underwriter or underwriters are utilized in the sale of
any Debt Securities, unless otherwise set forth in the applicable Prospectus
Supplement, the underwriting agreement will provide that the obligations of the
underwriters will be subject to certain conditions precedent and that the
underwriters with respect to a sale of such Debt Securities will be obligated to
purchase all such Debt Securities if any are purchased.
 
     If a dealer is utilized in the sale of any Debt Securities in respect of
which this Prospectus is delivered, the Company will sell such Debt Securities
to the dealer, as principal. The dealer may then resell such Debt Securities to
the public at varying prices to be determined by such dealer at the time of
resale. Any such dealer may be deemed to be an underwriter, as such term is
defined in the Securities Act, of the Debt Securities so offered and sold.
Dealers may be entitled, under agreements which may be entered into with the
Company, to indemnification by the Company against certain liabilities,
including liabilities under the Securities Act. The name of the dealer and the
terms of the transaction will be set forth in a Prospectus Supplement relating
thereto.
 
     Offers to purchase Debt Securities may be solicited directly by the Company
and sales thereof may be made by the Company directly to institutional investors
or others, who may be deemed to be underwriters within the meaning of the
Securities Act with respect to any sale thereof. The terms of any such sales
will be described in a Prospectus Supplement relating thereto.
 
     If so indicated in an appropriate Prospectus Supplement, the Company may
authorize agents and underwriters to solicit offers by certain institutions to
purchase Debt Securities from the Company at the public offering price set forth
in such Prospectus Supplement pursuant to delayed delivery contracts
("Contracts") providing for payment and delivery on the date stated in such
Prospectus Supplement. Each Contract will be for an amount not less than and,
unless the Company otherwise agrees, the aggregate principal amount of Debt
Securities sold pursuant to Contracts shall be not less nor more than the
respective amounts stated in such Prospectus Supplement. Institutions with whom
Contracts, when authorized, may be made include commercial and savings banks,
insurance companies, pension funds, investment companies, educational and
charitable institutions and other institutions, but shall in all cases be
subject to the approval of the Company in its sole discretion. The obligations
of a purchaser under any Contract will not be subject to
 
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<PAGE>   17
 
any conditions except that any related sale of Debt Securities to underwriters
shall have occurred and the purchase by an institution of the Debt Securities
covered by its Contract shall not at the time of delivery be prohibited under
the laws of any jurisdiction in the United States to which such institution is
subject. A commission indicated in such Prospectus Supplement will be paid to
underwriters and agents soliciting purchases of Debt Securities pursuant to
Contracts accepted by the Company. The underwriters or agents will not have any
responsibility in respect of the validity or performance of Contracts.
 
     The place and time of delivery of the Debt Securities in respect of which
this Prospectus is delivered will be set forth in an accompanying Prospectus
Supplement.
 
                                 LEGAL MATTERS
 
     Unless otherwise indicated in a Prospectus Supplement relating to the Debt
Securities, certain legal matters in connection with the Debt Securities will be
passed upon for the Company by Baker & Hostetler, Cleveland, Ohio. Certain legal
matters in connection with the Debt Securities offered hereby will be passed
upon for any purchasers, dealers, underwriters or agents by Stroock & Stroock &
Lavan, New York, New York. Stroock & Stroock & Lavan may rely as to all matters
of Ohio law on the opinion of Baker & Hostetler, and Baker & Hostetler may rely
as to all matters of New York law on the opinion of Stroock & Stroock & Lavan.
Stroock & Stroock & Lavan has represented the Company from time to time and may
continue to represent the Company in connection with certain legal matters.
 
                                    EXPERTS
 
     The consolidated financial statements and schedules of The Progressive
Corporation and subsidiaries as of December 31, 1992, and for each of the years
in the three-year period then ended, all incorporated by reference in the
Registration Statement of which this Prospectus forms a part, have been
incorporated herein in reliance on the report of Coopers & Lybrand, independent
accountants, given on the authority of that firm as experts in accounting and
auditing.
 
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