<PAGE>
                                                                     EXHIBIT 4.7

                            W.R. BERKLEY CORPORATION

                                       TO

                        THE BANK OF NEW YORK, as Trustee

                -------------------------------------------------------
                         FIFTH SUPPLEMENTAL INDENTURE TO
                        INDENTURE DATED FEBRUARY 14, 2003
                            (SENIOR DEBT SECURITIES)

                          Dated as of February 14, 2007

                -------------------------------------------------------

                          6.250% Senior Notes due 2037

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                                TABLE OF CONTENTS
<TABLE>
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<S>                                                                                               <C>
                                    ARTICLE I

                       Relation to Indenture; Definitions

Section 1.1.    RELATION TO INDENTURE..........................................................   1
Section 1.2.    DEFINITIONS....................................................................   1

                                   ARTICLE II

                            The Series of Securities

Section 2.1.    TITLE OF THE SECURITIES........................................................   2
Section 2.2.    LIMITATION ON AGGREGATE PRINCIPAL AMOUNT.......................................   2
Section 2.3.    PRINCIPAL PAYMENT DATE.........................................................   2
Section 2.4.    INTEREST AND INTEREST RATES....................................................   2
Section 2.5.    PLACE OF PAYMENT...............................................................   3
Section 2.6.    REDEMPTION.....................................................................   3
Section 2.7.    DENOMINATION...................................................................   5
Section 2.8.    CURRENCY.......................................................................   5
Section 2.9.    FORM OF NOTES..................................................................   5
Section 2.10.   REGISTRAR AND PAYING AGENT FOR THE NOTES.......................................   5
Section 2.11.   SINKING FUND OBLIGATIONS.......................................................   5
Section 2.12.   DEFEASANCE AND COVENANT DEFEASANCE.............................................   5
Section 2.13.   PAYMENT OF TAXES...............................................................   5
Section 2.14.   LIMITATION ON LIENS ON STOCK OF PRINCIPAL SUBSIDIARIES.........................   5
Section 2.15.   LIMITATIONS ON ISSUE OR DISPOSITION OF COMMON STOCK OF PRINCIPAL SUBSIDIARIES..   6
Section 2.16.   IMMEDIATELY AVAILABLE FUNDS....................................................   6

                                   ARTICLE III

                            Miscellaneous Provisions

Section 3.1.    TRUSTEE NOT RESPONSIBLE FOR RECITALS...........................................   6
Section 3.2.    PAYMENT OF EXPENSES UPON RESIGNATION OR REMOVAL................................   7
Section 3.3.    ADOPTION, RATIFICATION AND CONFIRMATION........................................   7
Section 3.4.    COUNTERPARTS...................................................................   7
Section 3.5.    GOVERNING LAW..................................................................   7
</TABLE>

<PAGE>

                           W. R. BERKLEY CORPORATION

                         FIFTH SUPPLEMENTAL INDENTURE TO
                        INDENTURE DATED FEBRUARY 14, 2003
                            (SENIOR DEBT SECURITIES)

                                  $250,000,000

                          6.250% Senior Notes due 2037

      FIFTH SUPPLEMENTAL INDENTURE, dated as of February 14, 2007 between W. R.
BERKLEY CORPORATION, a Delaware corporation (the "Company"), and THE BANK OF NEW
YORK, a banking corporation organized under the laws of the State of New York,
as Trustee (the "Trustee").

                                    RECITALS

      The Company has heretofore executed and delivered to the Trustee an
indenture for senior debt securities, dated as of February 14, 2003 (the
"Indenture"), providing for the issuance from time to time of series of the
Company's Securities.

      Section 3.1 of the Indenture provides for various matters with respect to
any series of Securities issued under the Indenture to be established in an
indenture supplemental to the Indenture.

      Section 9.1(4) of the Indenture provides for the Company and the Trustee
to enter into an indenture supplemental to the Indenture to establish the form
or terms of Securities of any series as provided by Sections 2.1 and 3.1 of the
Indenture.

      NOW, THEREFORE, THIS FIFTH SUPPLEMENTAL INDENTURE WITNESSETH:

      For and in consideration of the premises and the issuance of the series of
Securities provided for herein, it is mutually agreed, for the equal and
proportionate benefit of all Holders of the Securities of such series, as
follows:

                                   ARTICLE I

                       RELATION TO INDENTURE; DEFINITIONS

      Section 1.1. RELATION TO INDENTURE. This Fifth Supplemental Indenture
constitutes an integral part of the Indenture.

      Section 1.2. DEFINITIONS. For all purposes of this Fifth Supplemental
Indenture:

                                       1
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      (a) Capitalized terms used herein without definition shall have the
meanings specified in the Indenture;

      (b) All references herein to Articles and Sections, unless otherwise
specified, refer to the corresponding Articles and Sections of this Fifth
Supplemental Indenture; and

      (c) The terms "herein," "hereof," "hereunder" and other words of similar
import refer to this Fifth Supplemental Indenture.

      (d) "Fair Value," when used with respect to Common Stock, means the fair
value thereof as determined in good faith by the Board of Directors.

                                   ARTICLE II

                            THE SERIES OF SECURITIES

      Section 2.1. TITLE OF THE SECURITIES. There shall be a series of
Securities designated the "6.250% Senior Notes due 2037" (the "Notes").

      Section 2.2. LIMITATION ON AGGREGATE PRINCIPAL AMOUNT. The aggregate
principal amount of the Notes shall initially be limited to $250,000,000. The
Company may, without the consent of the Holders of the Notes, issue additional
Securities having the same interest rate, maturity date and other terms as
described in the related prospectus supplement and prospectus. Any additional
Securities, together with the Notes offered by the related prospectus
supplement, will constitute a single series of Securities under the Indenture.
No additional Securities may be issued if an Event of Default under the
Indenture has occurred and is continuing with respect to the Securities.

      Section 2.3. PRINCIPAL PAYMENT DATE. The principal amount of the Notes
outstanding (together with any accrued and unpaid interest) shall be payable in
a single installment on February 15, 2037, which date shall be the Stated
Maturity of the Notes Outstanding.

      Section 2.4. INTEREST AND INTEREST RATES. The rate of interest on each
Note shall be 6.250% per annum, accruing from February 14, 2007, or from the
most recent interest payment date (each such date, an "Interest Payment Date")
to which interest has been paid or duly provided for, payable semiannually in
arrears on February 15 and August 15 of each year commencing August 15, 2007
until the principal thereof shall have become due and payable, and until the
principal thereof is paid or duly provided for or made available for payment.
The amount of interest payable on any Interest Payment Date shall be computed on
the basis of a 360-day year of twelve 30-day months. The amount of interest
payable for any partial period shall be computed on the basis of the actual
number of days elapsed in a 360-day year of twelve 30-day months. In the event
that any date on which interest is payable on any Note is not a Business Day,
then payment of interest payable on such date will be made on the next
succeeding day that is a Business Day (and without any interest or other payment
in respect of any such delay). The interest installment so payable in respect of
any Note, and punctually paid or duly provided for, on any Interest Payment Date
will, as provided in the Indenture, be paid to

                                       2
<PAGE>

the person in whose name such Note (or one or more Predecessor Securities) is
registered at the close of business on February 1 or August 1 prior to such
Interest Payment Date. Any such interest installment not punctually paid or duly
provided for in respect of any Note shall forthwith cease to be payable to the
registered Holder on such Regular Record Date and may either be paid to the
Person in whose name such Note (or one or more Predecessor Securities) is
registered at the close of business on a Special Record Date to be fixed by the
Company and the Trustee for the payment of such Defaulted Interest, notice
whereof shall be given to the Holders of the Notes not less than 10 days prior
to such Special Record Date, or be paid at any time in any other lawful manner
not inconsistent with the requirements of any securities exchange on which the
Notes may be listed, and upon such notice as may be required by such exchange,
all as more fully provided in the Indenture.

      Section 2.5. PLACE OF PAYMENT. The Place of Payment where the Notes may be
presented or surrendered for payment, where the Notes may be surrendered for
registration of transfer or exchange and where notices and demand to or upon the
Company in respect of the Notes and the Indenture may be served shall be the
Corporate Trust Office of the Trustee.

      Section 2.6. REDEMPTION.

      (a) The Company may redeem the Notes, in whole or in part, at any time at
a Redemption Price equal to the greater of (i) 100% of the principal amount of
such Securities to be redeemed or (ii) an amount, as determined by an
Independent Investment Banker, equal to the sum of the present values of the
remaining scheduled payments of principal of and interest on the securities to
be redeemed (not including any portion of such payments of interest accrued as
of the date of redemption) discounted to the Redemption Date on a semiannual
basis (assuming a 360-day year consisting of twelve 30-day months) at the
Adjusted Treasury Rate, plus 25 basis points, plus, in either of the above
cases, accrued and unpaid interest thereon to, but not including, the Redemption
Date.

      (b) For the purposes of this Section 2.6,

      "Adjusted Treasury Rate" means, with respect to any Redemption Date:

      -     the yield, under the heading which represents the average for the
            immediately preceding week, appearing in the most recently published
            statistical release designated "H.15(519)" published by the Board of
            Governors of the Federal Reserve System (or any successor
            publication which is published weekly by the Board of Governors of
            the Federal Reserve System and which establishes yields on actively
            traded United States Treasury securities adjusted to constant
            maturity) under the caption "Treasury Constant Maturities," for the
            maturity corresponding to the Comparable Treasury Issue. If no
            maturity is within three months before or after the Remaining Life,
            yields for the two published maturities most closely corresponding
            to the Comparable Treasury Issue shall be determined and the
            Adjusted Treasury Rate shall be interpolated or

                                       3
<PAGE>

            extrapolated from such yields on a straight line basis, rounding to
            the nearest month; or

      -     if such release (or any successor release) is not published during
            the week preceding the calculation date or does not contain such
            yields, the rate per annum equal to the semi-annual equivalent yield
            to maturity of the Comparable Treasury Issue, calculated using a
            price for the Comparable Treasury Issue (expressed as a percentage
            of its principal amount) equal to the Comparable Treasury Price for
            such Redemption Date.

      The Adjusted Treasury Rate shall be calculated on the third Business Day
preceding the Redemption Date.

      "Comparable Treasury Issue" means the United States Treasury security
selected by an Independent Investment Banker as having a maturity comparable to
the remaining term of the notes to be redeemed that would be utilized, at the
time of selection and in accordance with customary financial practice, in
pricing new issues of corporate debt securities of comparable maturity to the
remaining term of such securities ("Remaining Life").

      "Comparable Treasury Price" means (i) the average of three Reference
Treasury Dealer Quotations for such Redemption Date, after excluding the highest
and lowest Reference Treasury Dealer Quotations, or (ii) if the Independent
Investment Banker obtains fewer than three such Reference Treasury Dealer
Quotations, the average of all such quotations.

      "Independent Investment Banker" means one of the Reference Treasury
Dealers appointed by us.

      "Reference Treasury Dealer" means:

      -     each of Citigroup Global Markets Inc. and Credit Suisse Securities
            (USA) LLC and their respective successors; provided that, if any of
            the foregoing ceases to be a primary U.S. Government securities
            dealer in the United States (a "Primary Treasury Dealer"), the
            Company shall substitute therefor another Primary Treasury Dealer;
            and

      -     any other Primary Treasury Dealer selected by the Company.

      "Reference Treasury Dealer Quotations" means, with respect to each
Reference Treasury Dealer and any Redemption Date, the average, as determined by
the Independent Investment Banker, of the bid and asked prices for the
Comparable Treasury Issue (expressed in each case as a percentage of its
principal amount) quoted in writing to the Independent Investment Banker at 5:00
p.m., New York City Time, on the third Business Day preceding such Redemption
Date.

      The Company will mail a notice of redemption at least 30 days but not more
than 60 days before the Redemption Date to each holder of the notes to be
redeemed. If less than all

                                       4
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of the notes are to be redeemed, the trustee will select, by such method as it
will deem fair and appropriate, including pro rata or by lot, the notes to be
redeemed in whole or in part.

      Unless the Company defaults in payment of the Redemption Price, on and
after the Redemption Date, interest will cease to accrue on the notes or
portions thereof called for redemption.

      Section 2.7. DENOMINATION. The Notes shall be issuable only in registered
form without coupons and in denominations of $1,000 and integral multiples
thereof.

      Section 2.8. CURRENCY. Principal and interest on the Notes shall be
payable in such coin or currency of the United States of America that at the
time of payment is legal tender for payment of public and private debts.

      Section 2.9. FORM OF NOTES. The Notes shall be substantially in the form
attached as EXHIBIT A hereto.

      Section 2.10. REGISTRAR AND PAYING AGENT FOR THE NOTES. The Trustee shall
serve initially as Registrar and Paying Agent for the Notes.

      Section 2.11. SINKING FUND OBLIGATIONS. The Company has no obligation to
redeem or purchase any Notes pursuant to any sinking fund or analogous
requirement or upon the happening of a specified event or at the option of a
Holder thereof.

      Section 2.12. DEFEASANCE AND COVENANT DEFEASANCE. The Company has elected
to have both Section 4.2(2) of the Indenture (relating to defeasance) and
Section 4.2(3) (relating to covenant defeasance) applied to the Notes.

      Section 2.13. PAYMENT OF TAXES. The Company will pay or discharge or cause
to be paid or discharged, before the same shall become delinquent, all taxes,
assessments and governmental charges levied or imposed upon the Company or any
Subsidiary or upon the income, profits or property of the Company or any
Subsidiary, and lawful claims for labor, materials and supplies, which, if
unpaid, might by law become a lien upon the property of the Company or any
Subsidiary; provided, however, that the Company shall not be required to pay or
discharge or cause to be paid or discharged any such tax, assessment or
governmental charge whose amount, applicability or validity is being contested
in good faith by appropriate proceedings or where the failure to effect such
payment is not adverse in any material respect to the Holders of the Notes.

      Section 2.14. LIMITATION ON LIENS ON STOCK OF PRINCIPAL SUBSIDIARIES. The
Company will not, and it will not permit any Subsidiary of the Company to, at
any time directly or indirectly create, assume, incur or permit to exist any
Indebtedness secured by a pledge, lien or other encumbrance (any pledge, lien or
other encumbrance being hereinafter in this Section referred to as a "lien") on
the voting securities of Principal Subsidiaries, or the voting securities of a
Subsidiary that owns, directly or indirectly, the voting securities of any of
the Principal Subsidiaries without making effective provision whereby the Notes
then Outstanding (and, if the Company so elects, any other Indebtedness of the
Company

                                       5
<PAGE>

that is not subordinate to the Notes and with respect to which the governing
instruments require, or pursuant to which the Company is otherwise obligated or
required, to provide such security) shall be equally and ratably secured with
such secured Indebtedness so long as such other Indebtedness shall be secured.
For purposes of this Section 2.14 only, "Indebtedness", in addition to those
items specified in Section 1.1 of the Indenture, shall include any obligation
of, or any such obligation guaranteed by, any Person for the payment of amounts
due under a swap agreement or other similar instrument or agreement or foreign
currency hedge exchange or similar instrument or agreement.

      If the Company shall hereafter be required to secure the Notes equally and
ratably with any other Indebtedness pursuant to this Section, (i) the Company
will promptly deliver to the Trustee an Officer's Certificate stating that the
foregoing covenant has been complied with, and an Opinion of Counsel stating
that in the opinion of such counsel the foregoing covenant has been complied
with and that any instruments executed by the Company or any Subsidiary of the
Company in the performance of the foregoing covenant comply with the
requirements of the foregoing covenant and (ii) the Trustee is hereby authorized
to enter into an indenture or agreement supplemental hereto and to take such
action, if any, as it may deem advisable to enable it to enforce the rights of
the holders of the Notes so secured.

      Section 2.15. LIMITATIONS ON ISSUE OR DISPOSITION OF COMMON STOCK OF
PRINCIPAL SUBSIDIARIES. As long as any of the Notes remain outstanding, the
Company will not, and will not permit any Subsidiary to, issue, sell, assign,
transfer or otherwise dispose of, directly or indirectly, any of the Common
Stock of any Principal Subsidiary (except to the Company or to one or more
Subsidiaries or for the purpose of qualifying directors); provided, however,
that this covenant shall not apply if (i) the issuance, sale, assignment,
transfer or other disposition is required to comply with the order of a court or
regulatory authority of competent jurisdiction, other than an order issued at
the request of the Company or of one of its Subsidiaries; (ii) the entire Common
Stock of a Principal Subsidiary then owned by the Company or by its Subsidiaries
is disposed of in a single transaction or in a series of related transactions,
for consideration consisting of cash or other property which is at least equal
to the Fair Value of such Common Stock; or (iii) after giving effect to the
issuance, sale, assignment, transfer or other disposition, the Company and its
Subsidiaries would own directly or indirectly at least 80% of the issued and
outstanding Common Stock of such Principal Subsidiary and such issuance, sale,
assignment, transfer or other disposition is made for consideration consisting
of cash or other property which is at least equal to the Fair Value of such
Common Stock.

      Section 2.16. IMMEDIATELY AVAILABLE FUNDS. All payments of principal and
interest shall be made in immediately available funds.

                                  ARTICLE III

                            MISCELLANEOUS PROVISIONS

      Section 3.1. TRUSTEE NOT RESPONSIBLE FOR RECITALS. The recitals herein
contained are made by the Company and not by the Trustee, and the Trustee
assumes no

                                       6
<PAGE>

responsibility for the correctness thereof. The Trustee makes no representation
as to the validity or sufficiency of this Fifth Supplemental Indenture.

      Section 3.2. PAYMENT OF EXPENSES UPON RESIGNATION OR REMOVAL. Upon
termination of this Fifth Supplemental Indenture or the Indenture or the removal
or resignation of the Trustee, unless otherwise stated, the Company shall pay to
the Trustee all amounts accrued to the date of such termination, removal or
resignation.

      Section 3.3. ADOPTION, RATIFICATION AND CONFIRMATION. The Indenture, as
supplemented and amended by this Fifth Supplemental Indenture, is in all
respects hereby adopted, ratified and confirmed.

      Section 3.4. COUNTERPARTS. This Fifth Supplemental Indenture may be
executed in any number of counterparts, each of which shall be an original, but
such counterparts shall together constitute but one and the same instrument.

      Section 3.5. GOVERNING LAW. THIS FIFTH SUPPLEMENTAL INDENTURE AND EACH
NOTE SHALL BE DEEMED TO BE A CONTRACT MADE UNDER THE LAWS OF THE STATE OF NEW
YORK AND SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE
STATE OF NEW YORK WITHOUT REGARD TO CONFLICTS OF LAWS PRINCIPLES THEREOF.

                                       7
<PAGE>

      IN WITNESS WHEREOF, the parties hereto have caused this Fifth Supplemental
Indenture to be duly executed on the day and year first above written.

                                     W. R. BERKLEY CORPORATION

                                     By: /s/ Eugene G. Ballard
                                         ----------------------------
                                         Name:  Eugene G. Ballard
                                         Title: Senior Vice President


                                     THE BANK OF NEW YORK, as Trustee

                                     By: /s/ Geovanni Barris
                                         ----------------------------
                                        Name:  Geovanni Barris
                                        Title: Vice President

                                       8
<PAGE>
                                                                       EXHIBIT A

                             (FORM OF FACE OF NOTE)

      This Note is a global Note within the meaning of the Indenture hereinafter
referred to and is registered in the name of a Depository or a nominee of a
Depository. This Note is exchangeable for Securities registered in the name of a
person other than the Depository or its nominee only in the limited
circumstances described in the Indenture, and no transfer of this Note (other
than a transfer of this Note as a whole by the Depository to a nominee of the
Depository or by a nominee of the Depository to the Depository or another
nominee of the Depository) may be registered except in limited circumstances.

      Unless this Note is presented by an authorized representative of The
Depository Trust Company (55 Water Street, New York, New York) to the issuer or
its agent for registration of transfer, exchange or payment, and any Note issued
is registered in the name of Cede & Co. or such other name as requested by an
authorized representative of The Depository Trust Company and any payment hereon
is made to Cede & Co., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR
OTHERWISE BY A PERSON IS WRONGFUL since the registered owner hereof, Cede & Co.,
has an interest herein.

Certificate No. 5                                                   $250,000,000
Dated: February 14, 2007                                     CUSIP No. 084423AP7
                                                           ISIN No. US084423AP79

                           W. R. BERKLEY CORPORATION

                          6.250% Senior Notes due 2037

      W. R. BERKLEY CORPORATION, a Delaware corporation (the "Company," which
term includes any successor corporation under the Indenture hereinafter referred
to), for value received, hereby promises to pay to CEDE & CO. or registered
assigns, the principal sum of TWO HUNDRED AND FIFTY MILLION DOLLARS AND NO CENTS
($250,000,000.00) on February 15, 2037. The Company further promises to pay
interest on said principal sum outstanding from February 14, 2007, or from the
most recent interest payment date (each such date, an "Interest Payment Date")
to which interest has been paid or duly provided for, semiannually (subject to
deferral as set forth herein) in arrears on February 15 and August 15 of each
year commencing August 15, 2007 at the rate of 6.250% per annum, until the
principal hereof shall have become due and payable and, until the principal
hereof is paid or duly provided for or made available for payment. The amount of
interest payable on any Interest Payment Date shall be computed on the basis of
a 360-day year of twelve 30-day months. The amount of interest payable for any
partial period shall be computed on the basis of the number of actual days
elapsed in a 360-day year of twelve 30-day months. In the event that any date on
which interest is payable on this Note is not a Business Day, then payment of
interest payable on such date will be made on the next succeeding day that is a
Business Day (and without any interest or other payment in respect of any such
delay). A "Business Day," with respect to any Place of

                                      A-1
<PAGE>

Payment or other location, shall mean any day other than a Saturday, Sunday or
other day on which banking institutions in such Place of Payment or other
location are authorized or obligated by law, regulation or executive order to
close. The interest installment so payable, and punctually paid or duly provided
for, on any Interest Payment Date will, as provided in the Indenture, be paid to
the Person in whose name this Note (or one or more Predecessor Securities) is
registered at the close of business on February 1 or August 1 prior to such
Interest Payment Date. Any such interest installment not punctually paid or duly
provided for shall forthwith cease to be payable to the registered Holder on
such Regular Record Date and may either be paid to the Person in whose name this
Note (or one or more Predecessor Securities) is registered at the close of
business on a Special Record Date to be fixed by the Trustee for the payment of
such Defaulted Interest, notice whereof shall be given to the Holder of this
Note not less than 10 days prior to such Special Record Date, or be paid at any
time in any other lawful manner not inconsistent with the requirements of any
securities exchange on which this Note may be listed, and upon such notice as
may be required by such exchange, all as more fully provided in the Indenture.

      The principal of (and premium, if any) and the interest on this Note shall
be payable at the office or agency of the Company maintained for that purpose in
the United States in such coin or currency of the United States of America that
at the time of payment is legal tender for payment of public and private debts;
PROVIDED, HOWEVER, that payment of interest may be made at the option of the
Company by check mailed to the registered Holder at such address as shall appear
in the Security Register. Notwithstanding the foregoing, so long as the Holder
of this Note is Cede & Co., the payment of the principal of (and premium, if
any) and interest on this Note will be made at such place and to such account as
may be designated by Cede & Co. All payments of principal and interest hereunder
shall be made in immediately available funds.

      Reference is hereby made to the further provisions of this Note set forth
on the reverse hereof, which further provisions shall for all purposes have the
same effect as if set forth at this place.

      Unless the certificate of authentication hereon has been executed by the
Trustee referred to on the reverse hereof by manual signature, this Note shall
not be entitled to any benefit under the Indenture or be valid for any purpose.

                                      A-2
<PAGE>

      IN WITNESS WHEREOF, the Company has caused this instrument to be executed.

                                     W. R. BERKLEY CORPORATION

                                     By:_______________________________
                                        Name:
                                        Title:

                          CERTIFICATE OF AUTHENTICATION

      This is one of the Securities of the series designated herein referred to
in the within-mentioned Indenture.

Dated:  February 14, 2007

THE BANK OF NEW YORK,
as Trustee

By:_____________________________
   Authorized Signatory

                                      A-3
<PAGE>

                            (FORM OF REVERSE OF NOTE)

      This Note is one of a duly authorized issue of securities of the Company,
designated as its 6.250% Senior Notes due 2037 (herein referred to as the
"Securities"), issued under and pursuant to an Indenture, dated as of February
14, 2003 between the Company and The Bank of New York, as Trustee (herein called
the "Trustee," which term includes any successor trustee under the Indenture),
as supplemented by the Fifth Supplemental Indenture dated as of February 14,
2007, between the Company and the Trustee (the Indenture as so supplemented, the
"Indenture"), to which Indenture and all indentures supplemental thereto
reference is hereby made for a description of the rights, limitations of rights,
obligations, duties and immunities thereunder of the Trustee, the Company and
the Holders of the Securities, and of the terms upon which the Securities are,
and are to be, authenticated and delivered.

            All terms used in this Note that are defined in the Indenture shall
have the meanings assigned to them in the Indenture.

            The Company may redeem the Securities, in whole or in part, at any
time at a Redemption Price equal to the greater of (i) 100% of the principal
amount of such Securities to be redeemed or (ii) an amount, as determined by an
Independent Investment Banker, the sum of the present values of the remaining
scheduled payments of principal of and interest thereon on the securities to be
redeemed (not including any portion of such payments of interest accrued to the
date of redemption) discounted to the Redemption Date on a semiannual basis
assuming a 360-day year consisting of twelve 30-day months) at the Adjusted
Treasury Rate, plus 25 basis points, plus, in either of the above cases, accrued
and unpaid interest thereon to the Redemption Date.

      "Adjusted Treasury Rate" means, with respect to any Redemption Date:

      -     the yield, under the heading which represents the average for the
            immediately preceding week, appearing in the most recently published
            statistical release designated "H.15(519)" published by the Board of
            Governors of the Federal Reserve System (or any successor
            publication which is published weekly by the Board of Governors of
            the Federal Reserve System and which establishes yields on actively
            traded United States Treasury securities adjusted to constant
            maturity) under the caption "Treasury Constant Maturities," for the
            maturity corresponding to the Comparable Treasury Issue. If no
            maturity is within three months before or after the Remaining Life,
            yields for the two published maturities most closely corresponding
            to the Comparable Treasury Issue shall be determined and the
            Adjusted Treasury Rate shall be interpolated or extrapolated from
            such yields on a straight line basis, rounding to the nearest month;
            or

      -     if such release (or any successor release) is not published during
            the week preceding the calculation date or does not contain such
            yields, the rate per annum equal to the semiannual equivalent yield
            to maturity of the

                                      A-4
<PAGE>

            Comparable Treasury Issue, calculated using a price for the
            Comparable Treasury Issue (expressed as a percentage of its
            principal amount) equal to the Comparable Treasury Price for such
            Redemption Date.

      The Adjusted Treasury Rate shall be calculated on the third Business Day
preceding the Redemption Date.

      "Comparable Treasury Issue" means the United States Treasury security
selected by an Independent Investment Banker as having a maturity comparable to
the remaining term of the securities to be redeemed that would be used, at the
time of selection and in accordance with customary financial practice, in
pricing new issues of corporate debt securities of comparable maturity to the
remaining term of such securities ("Remaining Life").

      "Comparable Treasury Price" means (i) the average of three Reference
Treasury Dealer Quotations for such Redemption Date, after excluding the highest
and lowest Reference Treasury Dealer Quotations, or (ii) if the Independent
Investment Banker obtains fewer than three such Reference Treasury Dealer
Quotations, the average of all such quotations.

      "Independent Investment Banker" means one of the Reference Treasury
Dealers appointed by us.

      "Reference Treasury Dealer" means:

      -     each of Citigroup Global Markets Inc. and Credit Suisse Securities
            (USA) LLC and their respective successors; provided, however, that
            if any of the foregoing shall cease to be a primary U.S. Government
            securities dealer in the United States (a "Primary Treasury
            Dealer"), the Company shall substitute therefor another Primary
            Treasury Dealer; and

      -     any other Primary Treasury Dealer selected by the Company.

      "Reference Treasury Dealer Quotations" means, with respect to each
Reference Treasury Dealer and any Redemption Date, the average, as determined by
the Independent Investment Banker, of the bid and asked prices for the
Comparable Treasury Issue (expressed in each case as a percentage of its
principal amount) quoted in writing to the Independent Investment Banker at 5:00
p.m., New York City Time, on the third Business Day preceding such Redemption
Date.

      The Company will mail a notice of redemption at least 30 days but not more
than 60 days before the Redemption Date to each holder of the securities to be
redeemed. If less than all of the securities are to be redeemed, the Trustee
will select, by such method as it will deem fair and appropriate, including pro
rata or by lot, the securities to be redeemed in whole or in part.

      Unless we default in payment of the Redemption Price, on and after the
Redemption Date, interest will cease to accrue on the securities or portions
thereof called for redemption.

                                      A-5
<PAGE>

      If an Event of Default with respect to Securities of this series shall
occur and be continuing, the principal of the Securities of this series may be
declared due and payable in the manner, with the effect and subject to the
conditions provided in the Indenture.

      The Indenture contains provisions for satisfaction, discharge and
defeasance at any time of the entire indebtedness of this Note upon compliance
by the Company with certain conditions set forth in the Indenture.

      The Indenture permits, with certain exceptions as therein provided, the
amendment thereof and the modification of the rights and obligations of the
Company and the rights of the Holders of the Securities of each series to be
affected under the Indenture at any time by the Company and the Trustee with the
consent of the Holders of a majority in principal amount of the Securities of
each series at the time Outstanding of each series to be affected. The Indenture
also contains provisions permitting Holders of specified percentages in
principal amount of the Securities of each series at the time Outstanding, on
behalf of the Holders of all Securities of such series, to waive compliance by
the Company with certain provisions of the Indenture and certain past defaults
under the Indenture and their consequences. Any such consent or waiver by the
Holder of this Note shall be conclusive and binding upon such Holder and upon
all future Holders of this Note and of any Note issued upon the registration of
transfer hereof or in exchange therefor or in lieu hereof, whether or not
notation of such consent or waiver is made upon this Note. No reference herein
to the Indenture and no provision of this Note or of the Indenture (other than
Section 4.2 of the Indenture) shall alter or impair the obligation of the
Company to pay the principal and interest on the Note at the times, place and
rate, and in the coin or currency, herein prescribed.

      As provided in the Indenture and subject to certain limitations therein
set forth, the transfer of this Note is registrable in the Security Register,
upon surrender of this Note for registration of transfer at the office or agency
of the Company maintained under Section 10.2 of the Indenture duly endorsed by,
or accompanied by a written instrument of transfer, in form satisfactory to the
Company and the Security Registrar, duly executed by the Holder hereof or his or
her attorney duly authorized in writing, and thereupon one or more new
Securities of this series, of authorized denominations and for the same
aggregate principal amount, will be issued to the designated transferee or
transferees. No service charge shall be made for any such registration of
transfer or exchange, but the Company may require payment of a sum sufficient to
cover any tax or other governmental charge payable in connection therewith.

      Prior to due presentment of this Note for registration of transfer, the
Company, the Trustee and any agent of the Company or the Trustee may treat the
Person in whose name this Note is registered as the owner hereof for all
purposes, whether or not this Note be overdue, and neither the Company, the
Trustee nor any such agent shall be affected by notice to the contrary.

      This global Note is exchangeable for Securities in definitive form only
under certain limited circumstances set forth in the Indenture. Securities of
this series so issued are issuable only in registered form without coupons in
denominations of $1,000 and any integral multiple thereof. As provided in the
Indenture and subject to certain limitations herein and

                                      A-6
<PAGE>

therein set forth, Securities of this series so issued are exchangeable for a
like aggregate principal amount of Securities of this series of a different
authorized denomination, as requested by the Holder surrendering the same.

      The Company and, by its acceptance of this Note or a beneficial interest
therein, the Holder of, and any Person that acquires a beneficial interest in,
this Note agree that for United States federal, state and local tax purposes it
is intended that this Note constitute indebtedness.

      THE INTERNAL LAWS OF THE STATE OF NEW YORK SHALL GOVERN THE INDENTURE AND
THE SECURITIES WITHOUT REGARD TO CONFLICT OF LAW PROVISIONS THEREOF.

                                      A-7