FORM OF CAPITAL SECURITY CERTIFICATE

                  This Capital  Security is a Global Security within the meaning
of the Declaration hereinafter referred to and is regis tered in the name of The
Depository  Trust  Company (the "Deposi  tary") or a nominee of the  Depositary.
This Capital Security is exchangeable for Capital  Securities  registered in the
name of a person  other than the  Depositary  or its nominee only in the limited
circumstances  described  in the  Declaration  and no transfer  of this  Capital
Security  (other  than a transfer  of this  Capital  Security  as a whole by the
Depositary to a nominee of the  Depositary or by a nominee of the  Depositary to
the Depositary or to another nominee of the Depositary) may be registered except
in limited circumstances.

                  Unless this Capital  Security is  presented  by an  authorized
representative  of The Depository Trust Company (55 Water Street,  New York, New
York) to the  Trust or its agent  for  registration  of  transfer,  exchange  or
payment, and any Capital Security 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.

THIS INSTRUMENT IS NOT A SAVINGS ACCOUNT OR A BANK DEPOSIT, IS NOT AN OBLIGATION
OF OR GUARANTEED BY ANY BANKING AFFILIATE OF NATIONSBANK  CORPORATION AND IS NOT
INSURED BY THE FEDERAL DEPOSIT INSURANCE  CORPORATION OR ANY OTHER  GOVERNMENTAL
AGENCY AND INVOLVES INVESTMENT RISKS, INCLUDING POSSIBLE LOSS OF PRINCIPAL.

Certificate Number

__-R-_____________                           CUSIP No. _______________
                                             ISIN No. ________________
                                             Common Code No.__________


             Certificate Evidencing __________ Floating Rate Capital
                                   Securities

                                       of

                              NB CAPITAL TRUST III


                        Floating Rate Capital Securities
                (liquidation amount $1,000 per Capital Security)

                  NB CAPITAL TRUST III, a statutory  business trust formed under
            the laws of the State of Delaware (the "Trust"), hereby






certifies  that  CEDE  &  CO.  (the   "Holder")  is  the  registered   owner  of
________________   Capital  Securities  of  the  Trust  representing   undivided
preferred  beneficial  interests  in the  assets  of the  Trust  designated  the
Floating  Rate  Capital  Securities  (liquida  tion  amount  $1,000 per  Capital
Security) (the "Capital Securities"). The Capital Securities are transferable on
the books and records of the Trust, in person or by a duly authorized  attorney,
upon  surrender  of this  certificate  duly  endorsed  and in  proper  form  for
transfer. The designation,  rights,  privileges,  restrictions,  preferences and
other terms and  provisions  of the Capital  Securities  represented  hereby are
issued and shall in all respects be subject to the provisions of the Amended and
Restated  Declaration of Trust of the Trust dated as of January __, 1997, as the
same  may be  amended  from  time to time  (the  "Declaration"),  including  the
designation  of the terms of the Capital  Securities  as set forth in Annex I to
the  Declaration.  Capitalized  terms used herein but not defined shall have the
meaning given them in the Declaration. The Holder is entitled to the benefits of
the Capital Securities Guarantee to the extent provided therein. The Declaration
permits the Sponsor to dissolve the Trust at any time.  The Sponsor will provide
a copy of the Declaration, the Capital Securities Guarantee and the Indenture to
a Holder with out charge upon  written  request to the Sponsor at its  principal
place of business.

                  Upon receipt of this  certificate,  the Holder is bound by the
Declaration and is entitled to the benefits thereunder.

                  By acceptance,  the Holder agrees to treat,  for United States
federal  income  tax  purposes,  the  Notes  as  indebtedness  and  the  Capital
Securities as evidence of indirect beneficial ownership of the Notes.

                  IN WITNESS WHEREOF, the Trust has executed this certificate as
of ____________, 1997.


                                            NB CAPITAL TRUST III


                                            By:________________________________
                                                Name: John E. Mack
                                                Title: Regular Trustee



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                          [FORM OF REVERSE OF SECURITY]

                  Distributions payable on each Capital Security will be payable
in respect of the  liquidation  amount of $1,000 per capital  security at a rate
per annum equal to LIBOR plus ___%, such rate being the rate of interest payable
on the  Notes  to be  held by the  Property  Trustee  on  behalf  of the  Trust.
Distributions  in  arrears  will  continue  to  accumulate  at  the  same  rate,
compounded quarterly. A Distribution is payable only to the extent that payments
are made in respect of the Notes held by the Property  Trustee and to the extent
the Property Trustee has funds available  therefor.  The amount of Distributions
payable for any period will be computed on the basis of a 360-day year of twelve
30-day months.

                  Accrued  Distributions  on any Security  will be calculated by
multiplying the principal amount of such Security by an accrued interest factor.
Such  accrued  interest  factor will be computed by adding the  interest  factor
calculated  for  each  day from and  including  ___________,  1997,  or from but
excluding the last date to which  interest has been paid, as the case may be, to
and  including  the date for which  accrued  interest is being  calculated.  The
interest  factor  (expressed  as a  decimal)  for each such day is  computed  by
dividing the rate in effect on such day by 360. All  percentages  resulting from
any  calculation  of  Distributions  on the  securities  will be  rounded to the
nearest one  hundred-thousandth of a percentage point, with five one- millionths
of a percentage  point rounded upward (e.g.,  5.687665% (or .05687665)  would be
rounded to 5.68767%  (or  .0568767)),  and all dollar  amounts used or resulting
from such  calculation  will be rounded to the nearest cent (with  one-half cent
being rounded upward).

                  Except as  otherwise  described  below,  Distributions  on the
Capital  Securities  will be  cumulative,  will accrue from the date of original
issuance and will be payable quarterly in ar rears on January 15, April 15, July
15 and  October 15 of each year,  commencing  on April 15, 1997 to the person in
whose name the Capital  Security is  registered  at the close of business on the
regular record date for such  installment,  which shall be the close of business
on the Business Day next  preceding  such payment date. IF PURSUANT TO THE TERMS
OF THE  DECLARATION,  THE  SECURITIES  ARE NO  LONGER  REPRESENTED  BY A  GLOBAL
SECURITY  -- which  shall be the close of business on January 1, April 1, July 1
or  October  1. The Note  Issuer  has the right  under  the Inden  ture to defer
payments of interest by extending the interest pay ment period from time to time
on the Notes for a period not exceeding 20 consecutive  quarterly  periods (each
an "Extension Period"),  provided that no Extension Period shall last beyond the
date  of  the  maturity  of  the  Notes.  As a  consequence  of  such  deferral,
Distributions will also be deferred hereunder for the same period.  Despite such
deferral,  quarterly  Distributions to which Holders of such Capital  Securities
are entitled will con tinue to accumulate additional  Distributions thereon at a
rate per annum equal to LIBOR plus ___%,  compounded quarterly from the relevant
payment  date  for such  Distributions.  Prior  to the  termination  of any such
Extension Period, the Note Issuer may


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further  extend  such  Extension  Period;  provided  that such Exten sion Period
together  with all such  previous and further exten sions thereof may not exceed
20  consecutive  quarterly  periods or extend  beyond the  maturity  date of the
Notes.  Payments  of  accrued  Distributions  will be payable to Holders as they
appear on the books and records of the Trust on the first  record date after the
end of the Extension  Period.  Upon the termination of any Extension  Period and
the  payment  of all  amounts  then due,  the Note  Issuer  may  commence  a new
Extension Period, subject to the above requirements.

                  THE CAPITAL SECURITIES SHALL BE REDEEMABLE AS PROVIDED
IN THE DECLARATION.


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


                                   ASSIGNMENT

FOR VALUE RECEIVED,  the undersigned assigns and transfers this Capital Security
Certificate to:

- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
        (Insert assignee's social security or tax identification number)

- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
                    (Insert address and zip code of assignee)


and irrevocably appoints

- --------------------------------------------------------------------------------
- ------------------------------------ agent to transfer this Capital Security 
Certificate on the books of the Trust. The agent may substitute another to act 
for him or her.


Date:
     --------------------------------------------

Signature:
          ---------------------------------------
(Sign exactly as your name appears on the other side of this Capital Security
Certificate)

Signature Guarantee*: 
                     -----------------------------------------------------------

- --------------------
*        Signature  must be  guaranteed by an "eligible  guarantor  institution"
         that is a bank,  stock broker,  savings and loan  association or credit
         union meeting the  requirements  of the Registrar,  which  requirements
         include  membership or participation in the Securities  Transfer Agents
         Medallion Program ("STAMP") or such other "signature guarantee program"
         as  may  be   determined  by  the  Registrar  in  addition  to,  or  in
         substitution  for,  STAMP,  all in accordance  with the  Securities and
         Exchange Act of 1934, as amended.


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