<PAGE>

                                                                     EXHIBIT 4.8

          UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE
OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), NEW YORK, NEW
YORK, TO THE COMPANY OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR
PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR
SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY
PAYMENT IS MADE TO CEDE & CO., OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN
AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR
VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED
OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

          TRANSFERS OF THIS GLOBAL SECURITY SHALL BE LIMITED TO TRANSFERS IN
WHOLE, BUT NOT IN PART, TO DTC, TO NOMINEES OF DTC OR TO A SUCCESSOR THEREOF OR
SUCH SUCCESSOR'S NOMINEE AND TRANSFERS OF PORTIONS OF THIS GLOBAL SECURITY SHALL
BE LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE RESTRICTIONS SET FORTH IN
THE INDENTURE REFERRED TO BELOW.


                    NATIONAL COMMERCE FINANCIAL CORPORATION


           [   ]% Junior Subordinated Deferrable Interest Debentures

No. R-1                                                               $


          NATIONAL COMMERCE FINANCIAL CORPORATION, a corporation organized and
existing under the laws of the State of Tennessee (hereinafter called the
"Company", which term includes any successor corporation under the Indenture
hereinafter referred to), for value received, hereby promises to pay to The Bank
of New York, as Property Trustee (the "Property Trustee") for National Commerce
Capital Trust II, a statutory business trust formed under the laws of the State
of Delaware, or registered assigns, the principal sum of [            ] ($[   ])
on [         ], 2001.  The Company further promises to pay interest on said
principal sum from              , 2001, or from the most recent interest payment
date on which interest has been paid or duly provided for, quarterly (subject to
deferral as set forth herein) in arrears on [          ], [          ],
[      ], and [        ] of each year (each, an "Interest Payment Date"),
commencing         , 2002.  The interest rate for the initial Interest Period
and for each Interest Period thereafter will be [   ]% per annum until the
principal hereof shall have become due and payable, plus Additional Interest
(as defined in the Indenture referred to on the reverse hereof) at the per
annum rate equal to [   ]% until the principal hereof is paid or duly provided
for or made available for payment and on any overdue principal at the per annum
rate equal to [  ]%.  "Interest Period" as used herein shall mean the period
beginning on and including [      ], 2001, and ending on but excluding the
first Interest Payment

<PAGE>

Date and each successive period beginning on and including an Interest Payment
Date and ending on but excluding the next succeeding Interest Payment Date. The
amount of interest payable for any Interest Period shall be computed on the
basis of a 360-day year of twelve 30-day months. In the event that any date on
which interest is payable on this Security is not a Business Day, then a payment
of the interest payable on such date will be made on the next succeeding day
which is a Business Day (without any interest or other payment in respect of
such delay), except that, if such Business Day would thereby fall in the next
calendar year, such payment shall be made on the immediately preceding Business
Day. The term "interest" as used herein shall include quarterly interest
payments and interest on quarterly interest payments not paid on the applicable
Interest Payment Date, as applicable. Notwithstanding anything to the contrary
set forth above, if the maturity date falls on a day that is not a Business Day,
the payment of principal and interest payable on such date will be made on the
next succeeding day that is a Business Day, and no interest or other payment
will accumulate for the period from and after the maturity date. A "Business
Day" shall mean any day other than (i) a Saturday or Sunday, (ii) a day on which
banking institutions in The City of New York are authorized or required by law
or executive order to remain closed, or (iii) a day on which the corporate trust
office of the Trustee is closed for business. 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
Security (or one or more Predecessor Securities) is registered at the close of
business on the Regular Record Date for such interest installment, which shall
be the Business Day next preceding such Interest Payment Date or, if this
Security is held in certificated form by any Holder other than the Property
Trustee or Cede & Co., the date which is fifteen days next preceding such
Interest Payment Date (whether or not a Business Day). Any such interest
installment not so punctually paid or duly provided for shall forthwith cease to
be payable to the Holder on such Regular Record Date and may either be paid to
the Person in whose name this Security (or one or more Predecessor Securities)
is registered at the close of business on a Special Record Date for the payment
of such Defaulted Interest to be fixed by the Trustee, notice whereof shall be
given to the Holder of this Security 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 or automated quotation system
on which the Securities of this series may be listed or traded, and upon such
notice as may be required by such exchange or self-regulatory organization, all
as more fully provided in said Indenture.

          So long as no Event of Default has occurred and is continuing, the
Company shall have the right at any time during the term of this Security to
defer payment of interest on this Security, at any time or from time to time,
for up to 20 consecutive quarterly Interest Periods with respect to each
deferral period (each an "Extension Period").  During any such Extension Period
the Company shall have the option to make partial payments of interest on any
Interest Payment Date, and at the end of any such Extension Period the Company
shall pay all interest then accrued and unpaid (together with Additional
Interest thereon to the extent permitted by applicable law); provided, however,
that no Extension Period shall extend beyond the Stated Maturity of the
principal of this Security; provided, further, that during any such Extension
Period, the Company shall not, and shall not permit any Subsidiary of the
Company to, (i) declare or pay any dividends or distributions on or redeem,
purchase, acquire or make a liquidation payment with respect to, any of the
Company's capital stock or (ii) make any payment of principal of or interest or
premium, if any,

                                       2
<PAGE>

on or repay, repurchase or redeem any debt security of the Company that ranks
pari passu with or junior in interest to this Security or (iii) make any
guarantee payments with respect to any guarantee by the Company of the debt
securities of any Subsidiary of the Company if such guarantee ranks pari passu
with or junior in interest to this Security (other than (a) dividends or
distributions in the Company's capital stock, (b) any declaration of a dividend
in connection with the implementation of a Rights Plan or the redemption or
repurchase of any rights distributed pursuant to a Rights Plan, (c) payments
under the Guarantee with respect to this Security, and (d) purchases of Common
Stock related to the issuance of Common Stock or rights under any of the
Company's benefit plans for its directors, officers or employees, related to the
issuance of Common Stock or rights under a dividend reinvestment and stock
purchase plan, or related to the issuance of Common Stock (or securities
convertible or exchangeable for Common Stock) as consideration in an acquisition
transaction that was entered into prior to the commencement of such Extension
Period). Prior to the termination of any such Extension Period, the Company may
further defer the payment of interest, provided that no Extension Period shall
exceed 20 consecutive quarterly Interest Periods or extend beyond the Stated
Maturity of the principal of this Security. Upon the termination of any such
Extension Period and upon the payment of all accrued and unpaid interest and any
Additional Interest then due, the Company may elect to begin a new Extension
Period, subject to the above requirements. No interest shall be due and payable
during an Extension Period except at the end thereof. The Company shall give the
Holder of this Security and the Trustee, the Property Trustee and the
Administrative Trustees notice of its election to begin any Extension Period at
least one Business Day prior to the next succeeding Interest Payment Date on
which interest on this Security would be payable but for such deferral or, with
respect to the Securities issued to a Trust, so long as such Securities are held
by such Trust, prior to the earlier of (i) the next succeeding date on which
Distributions on the Preferred Securities would be payable but for such deferral
or (ii) the date the Administrative Trustees are required to give notice to any
securities exchange or other applicable self-regulatory organization or to
holders of such Preferred Securities of the record date or the date such
Distributions are payable, but in any event not less than one Business Day prior
to such record date.

          Payment of principal of and interest on this Security will be made 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 as at the time
of payment is legal tender for payment of public and private debts; provided,
however, that at the option of the Company payment of interest may be made (i)
by check mailed to the address of the Person entitled thereto as such address
shall appear in the Securities Register or (ii) by wire transfer in immediately
available funds at such place and to such account as may be designated in
writing at least 15 days before the relevant Interest Payment Date by the Person
entitled thereto as specified in the Securities Register; provided further, that
for so long as this Security is held by the Property Trustee, payments of
principal of and interest on the Security shall be made by wire transfer in
immediately available funds to such account at the Property Trustee as the
Property Trustee may designate in writing to the Securities Registrar at least
one Business Day before the date such payment is due.

          The indebtedness evidenced by this Security is, to the extent provided
in the Indenture, subordinate and subject in right of payments to the prior
payment in full of all Senior Debt, and this Security is issued subject to the
provisions of the Indenture with respect thereto. Each

                                       3
<PAGE>

Holder of this Security, by accepting the same, (a) agrees to and shall be bound
by such provisions, (b) authorizes and directs the Trustee on his behalf to take
such actions as may be necessary or appropriate to effectuate the subordination
so provided and (c) appoints the Trustee his attorney-in-fact for any and all
such purposes. Each Holder hereof, by his acceptance hereof, waives all notice
of the acceptance of the subordination provisions contained herein and in the
Indenture by each holder of Senior Debt, whether now outstanding or hereafter
incurred, and waives reliance by each such holder upon said provisions.

          Reference is hereby made to the further provisions of this Security
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 Security
shall not be entitled to any benefit under the Indenture or be valid or
obligatory for any purpose.


          IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed under its corporate seal.


                              NATIONAL COMMERCE FINANCIAL CORPORATION,


                              By:
                                  ---------------------------------------
                                  Name:
                                  Title:


Attest:


------------------------------------
Name:
Title:

                                       4
<PAGE>

This is one of the Securities referred to in the within Indenture.


Dated:  December     , 2001


THE BANK OF NEW YORK,
 as Trustee,


By:
    ---------------------------------------
    Authorized Signatory

                                       5
<PAGE>

                             [Reverse of Security]

          This Security is one of a duly authorized issue of securities of the
Company (herein called the "Securities"), issued and to be issued in one or more
series under the Junior Subordinated Indenture, dated as of               , 2001
(herein called the "Indenture"), between the Company and The Bank of New York,
as Trustee (herein called the "Trustee", which term includes any successor
trustee under the Indenture), to which Indenture and all indentures supplemental
thereto reference is hereby made for a statement of the respective rights,
limitations of rights, 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. This Security is one
of the series designated on the face hereof, limited in aggregate principal
amount to $[                        ].

          All terms used in this Security that are defined in the Indenture or
in the Amended and Restated Trust Agreement, dated as of                , 2001,
as amended from time to time (the "Trust Agreement"), for National Commerce
Capital Trust II, among National Commerce Financial Corporation, as Depositor,
the Trustees named therein and the Holders (as defined therein), shall have the
meanings assigned to them in the Indenture or the Trust Agreement, as the case
may be.

          The Company may, at its option, on or after [             ], and
subject to the terms and conditions of Article XI of the Indenture, redeem this
Security in whole at any time or in part from time to time.

          Upon the occurrence and during the continuation of a Tax Event or a
Capital Treatment Event, in respect of a Trust, the Company may, at its option,
at any time within 90 days of the occurrence of such Tax Event or Capital
Treatment Event redeem this Security, in whole but not in part, subject to the
provisions of Section 11.07 and the other provisions of Article XI of the
Indenture, at a redemption price equal to 100% of the principal amount thereof
plus accrued and unpaid interest, including Additional Interest, if any, to the
Redemption Date.



                                       6
<PAGE>

          In all cases, the Redemption Price with respect to this Security shall
be equal to 100% of the principal amount of this Security plus accrued and
unpaid interest, including Additional Interest, if any, to the Redemption Date.

          This Security shall be subject to partial redemption only in the
amount of $25, or integral multiples thereof.

          In the event of redemption of this Security in part only, a new
Security or Securities for the unredeemed portion hereof will be issued in the
name of the Holder hereof upon the cancellation hereof.

          The provisions of Section 3.04 of the Indenture shall not apply to
this Security.

          The Indenture contains provisions for satisfaction and discharge of
the entire indebtedness of this Security upon compliance by the Company with
certain conditions set forth in the Indenture.

          The Indenture permits, with certain exceptions as therein provided,
the Company and the Trustee at any time to enter into a supplemental indenture
or indentures for the purpose of modifying in any manner the rights and
obligations of the Company and of the Holders of the Securities, with the
consent of the Holders of not less than a majority in principal amount of the
Outstanding Securities of this series. The Indenture also contains provisions
permitting Holders of specified percentages in principal amount of the
Securities of this series at the time Outstanding, on behalf of the Holders of
Securities of this 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 Security
shall be conclusive and binding upon such Holder and upon all

                                       7
<PAGE>

future Holders of this Security and of any Security issued upon the registration
of transfer hereof or in exchange hereof or in lieu hereof, whether or not
notation of such consent or waiver is made upon this Security.

          As provided in and subject to the provisions of the Indenture, if an
Event of Default with respect to the Securities of this series at the time
Outstanding occurs and is continuing, then and in every such case the Trustee or
the Holders of not less than 25% in principal amount of the Outstanding
Securities of this series may declare the principal amount of all the Securities
of this series to be due and payable immediately, by a notice in writing to the
Company (and to the Trustee if given by Holders), provided that, in the case of
the Securities of this series issued to a Trust, if upon an Event of Default,
the Trustee or the Holders of not less than 25% in principal amount of the
Outstanding Securities of this series fails to declare the principal of all the
Securities of this series to be immediately due and payable, the holders of at
least 25% in aggregate Liquidation Amount of the Preferred Securities then
outstanding shall have such right by a notice in writing to the Company and the
Trustee; and upon any such declaration the principal amount of and the accrued
interest (including any Additional Interest) on all the Securities of this
series shall become immediately due and payable, provided that the payment of
principal and interest (including any Additional Interest) on such Securities
shall remain subordinated to the extent provided in Article XIII of the
Indenture. The Holders of a majority in principal amount of the Outstanding
Securities of this series may annul such declaration and waive such default. If
the Holders of a majority in principal amount of the Outstanding Securities fail
to annul such declaration and waive such default, the holders of a majority in
aggregate Liquidation Amount of the Preferred Securities affected then
outstanding shall have such right.

          No reference herein to the Indenture and no provision of this Security
or of the Indenture shall alter or impair the obligation of the Company, which
is absolute and unconditional, to pay the principal of and interest on this
Security 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 Security is registrable in the
Securities Register, upon surrender of this Security for registration of
transfer at the office or agency of the Company maintained under Section 10.02
of the Indenture duly endorsed by, or accompanied by a written instrument of
transfer in form satisfactory to the Company and the Securities Registrar duly
executed by, the Holder hereof or his 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 Security 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 Security is registered as the owner
hereof for all purposes, whether or not this Security be overdue, and neither
the Company, the Trustee nor any such agent shall be affected by notice to the
contrary.

          The Securities of this series are issuable only in registered form
without coupons in denominations of $25 and any integral multiple thereof. As
provided in the Indenture and subject to certain limitations therein set forth,
Securities of this series are

                                       8
<PAGE>

exchangeable for a like aggregate principal amount of Securities of such series
of a different authorized denomination, as requested by the Holder surrendering
the same.

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

          THE INDENTURE AND THIS SECURITY SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

                                       9