<PAGE>   1
                                                                     Exhibit 4.1


                  UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"),
TO ISSUER OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT, AND
ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN 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.


No. 1
Cusip No. 637432501

                                      6,000,000 Subordinated Deferrable Interest
                                   Debentures (QUICS), $25 principal amount each


            NATIONAL RURAL UTILITIES COOPERATIVE FINANCE CORPORATION

                   7.625% QUARTERLY INCOME CAPITAL SECURITIES
             (SUBORDINATED DEFERRABLE INTEREST DEBENTURES DUE 2050)


                  NATIONAL RURAL UTILITIES COOPERATIVE FINANCE CORPORATION, a
cooperative association duly organized and existing under the laws of the
District of Columbia (herein referred to as the "Company", which term includes
any successor Person under the Indenture), for value received, hereby promises
to pay to CEDE & CO., or registered assigns, the principal sum of $150,000,000
on June 15, 2050, to pay interest on said principal sum from May 8, 2001 or from
the most recent Interest Payment Date through which interest has been paid or
duly provided for, quarterly in arrears on March 15, June 15, September 15 and
December 15 of each year, commencing June 15, 2001, at the rate of 7.625% per
annum to, but not including, the date on which the principal hereof is paid 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. In the event that any date on which interest is payable on the
Securities is not a Business Day, then payment of the interest payable on such
date will be made on the next succeeding day which is a Business Day (and
without any interest or other payment in respect of any such delay), except
that, if such Business Day is in the next succeeding calendar year, such payment
will be made on the immediately preceding Business Day, in each case with the
same force and effect as if made on such date. A "Business Day" is any day other
than a day on which banking institutions in New York City are authorized or
obligated by law to close. The interest so payable, and punctually paid or duly
provided for, on any Interest Payment Date will, as provided in such 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, which shall be the Business Day next preceding such Interest
Payment Date. Any such interest not so punctually paid or duly provided for will
<PAGE>   2

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 Holders of Securities of this series
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 Securities of this series may be listed, and
upon such notice as may be required by such exchange, all as more fully provided
in the Indenture referred to on the reverse hereof.

                  Payment of the principal of and interest on this Security will
be made at the office or agency of the Company maintained for that purpose in
the Borough of Manhattan, the City and State of New York, in such coin or
currency of the United States of America at the time of payment is legal tender
for payment of public and private debts.

                  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 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.

                                          NATIONAL RURAL UTILITIES
                                          COOPERATIVE FINANCE CORPORATION


                                          By:_______________________________

ATTEST:

______________________________
<PAGE>   3


                          CERTIFICATE OF AUTHENTICATION

Dated:  May 8, 2001


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


                                        BNY MIDWEST TRUST COMPANY



                                        By:______________________________
                                                 Authorized Signatory

<PAGE>   4
                                REVERSE OF QUICS

                  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 an Indenture, dated as of October 15, 1996, as amended
(herein called the "Indenture", which term shall have the meaning assigned to it
in such instrument), between the Company and BNY Midwest Trust Company, as
successor trustee (herein called the "Trustee", which term includes any
successor trustee under the Indenture), and reference is hereby made to the
Indenture for a statement of the respective rights, limitations of rights,
duties and immunities thereunder of the Company, the Trustee 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 in the initial principal amount of $150,000,000 (which principal
amount may be increased in accordance with the Indenture).

                  The Securities of this series are subject to redemption upon
not less than 30 nor more than 60 days' notice by mail, at any time on or after
June 15, 2006 as a whole or in part, at the election of the Company, at a
Redemption Price equal to 100% of the principal amount, together in the case of
any such redemption with accrued interest to, but not including, the Redemption
Date, but interest installments whose Stated Maturity is on or prior to such
Redemption Date will be payable to the Holder of such Security, or one or more
Predecessor Securities, of record at the close of business on the related
Regular Record Date referred to on the face hereof, all as provided in the
Indenture. If a partial redemption would result in a delisting of the Securities
from any national securities exchange on which the Securities are then listed,
the Company may redeem such Securities only in whole.

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

                  The indebtedness evidenced by this Security is, to the extent
provided in the Indenture, subordinated and subject in right of payment to the
prior payment in full of all Senior Indebtedness, and this Security is issued
subject to the provisions of the Indenture with respect thereto. Each 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
action as may be necessary or appropriate to acknowledge or 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, hereby
waives all notice of the acceptance of the subordination provisions contained
herein and in the Indenture by each holder of Senior Indebtedness, whether now
outstanding or hereafter incurred, and waives reliance by each such Holder upon
said provisions.

                  The Indenture contains provisions for defeasance at any time
of the entire indebtedness of this Security upon compliance with certain
conditions set forth in the Indenture.

                  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 and with the effect
provided in the Indenture.
<PAGE>   5

                  In addition to the events of default set forth in the
Indenture, the following will constitute an Event of Default under the Indenture
with respect to the Securities: the Company shall pay any dividend or interest
on, or principal of, or redeem, purchase, acquire or make a liquidation payment
with respect to, any Members' Subordinated Certificates, Members' Equity or
patronage capital, if such payment is made during an Extension Period, and
either (i) such Extension Period has not expired or been terminated or (ii) the
Company had not made all payments due on the Securities as a result of such
expiration or termination.

                  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 at the time Outstanding of each series to be affected. The
Indenture also contains provisions permitting the 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 Security shall be conclusive and binding upon such
Holder and upon all future Holders of this Security and of any Security issued
upon the registration of transfer hereof or in exchange herefor 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,
the Holder of this Security shall not have the right to institute any proceeding
with respect to the Indenture or for the appointment of a receiver or trustee or
for any other remedy thereunder, unless such Holder shall have previously given
the Trustee written notice of a continuing Event of Default with respect to the
Securities of this series, the Holders of not less than 33-1/3% in aggregate
principal amount of the Securities of this series at the time Outstanding shall
have made written request to the Trustee to institute proceedings in respect of
such Event of Default as Trustee and offered the Trustee reasonable indemnity,
and the Trustee shall not have received from the Holders of a majority in
aggregate principal amount of Securities of this series at the time Outstanding
a direction inconsistent with such request, and shall have failed to institute
any such proceeding, for 60 days after receipt of such notice, request and offer
of indemnity. The foregoing shall not apply to any suit instituted by the Holder
of this Security for the enforcement of any payment of principal hereof or
interest hereon on or after the respective due dates expressed herein.

                  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.

                  The Company shall have the right at any time and from time to
time during the term of the Securities of this series to extend the interest
payment period to a period not exceeding 20 consecutive quarters (an "Extended
Interest Payment Period"), and at the end of such Extended Interest Payment
Period or upon the date of the termination of the Extended Interest
<PAGE>   6
Payment Period if prior to the end, the Company shall pay all interest then
accrued and unpaid (together with interest thereon at the same rate as specified
for the Securities of this series to the extent permitted by applicable law)
through the last day of such Extended Interest Payment Period, provided that if
any principal amount of this Security is paid on such day, then not including
interest for such day with respect to such principal amount; provided, that
during such Extended Interest Payment Period the Company may not declare or pay
any dividend on, or redeem, purchase, acquire or make a liquidation payment with
respect to, any of its Members' Subordinated Certificates, Members' Equity or
patronage capital. Prior to the termination of any such Extended Interest
Payment Period, the Company may further extend the interest payment period,
provided that such Extended Interest Payment Period, together with all such
previous and further extensions thereof, may not exceed 20 consecutive quarters
or extend beyond the Stated Maturity of the Securities of this series. Upon the
termination of any such Extended Interest Payment Period and the payment of all
amounts then due, the Company may select a new Extended Interest Payment Period,
subject to the above requirements. No interest during an Extended Interest
Payment Period, except at the end thereof, shall be due and payable. The Company
shall give the Holder of this Security notice of its selection of such Extended
Interest Payment Period as provided in the Indenture.

                  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 exchangeable for a like aggregate principal
amount of Securities of this series and of like tenor and of authorized
denominations, as requested by the Holder surrendering the same.

                  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.

                  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
absolute 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.

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