<PAGE>

                                                                     EXHIBIT 4.4
                           3.40% Senior Notes due 2007
                          CERTIFICATE OF AUTHENTICATION

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

                                              J.P. MORGAN TRUST COMPANY,
                                              NATIONAL ASSOCIATION
                                              as Trustee,

                                                   By: _________________________
                                                       Name:
                                                       Title:

Dated:

<PAGE>

THIS DEBT SECURITY IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE
HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITARY OR A
NOMINEE THEREOF. THIS DEBT SECURITY MAY NOT BE EXCHANGED IN WHOLE OR IN PART FOR
A SECURITY REGISTERED, AND NO TRANSFER OF THIS DEBT SECURITY IN WHOLE OR IN PART
MAY BE REGISTERED, IN THE NAME OF ANY PERSON OTHER THAN SUCH DEPOSITARY OR A
NOMINEE THEREOF, EXCEPT IN THE LIMITED CIRCUMSTANCES DESCRIBED IN THE INDENTURE.

UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO BERKSHIRE HATHAWAY
FINANCE CORPORATION OR ITS AGENT FOR REGISTRATION OR 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.

<PAGE>

                     BERKSHIRE HATHAWAY FINANCE CORPORATION

                           3.40% SENIOR NOTES DUE 2007

                                                                          CUSIP:
                                                                           ISIN:

NO.                                                                   $[*******]
                                    (as revised by the Schedule of Increases and
                                   Decreases in Global Security attached hereto)

      BERKSHIRE HATHAWAY FINANCE CORPORATION, a corporation duly organized and
existing under the laws of the State of Delaware (herein called the "Company",
which term includes any successor Person under the Indenture hereinafter
referred to), for value received, hereby promises to pay to CEDE & CO., the
registered Holder hereof, the principal sum of [*******] ($[*******]) (as
revised by the Schedule of Increases and Decreases in Global Security attached
hereto) on July 2, 2007, and to pay interest thereon from and including July 19,
2004 or from and including the most recent Interest Payment Date (as defined
below) to which interest has been paid or duly provided for, semi-annually on
January 2 and July 2 in each year, commencing January 2, 2005 (each an "Interest
Payment Date"), at the rate of 3.40% per annum (as adjusted, if at all, pursuant
to such Indenture, the "Interest Rate"), until the principal hereof is paid or
made available for payment; provided that any principal, and any such
installment of interest, which is overdue shall bear interest at the Interest
Rate (to the extent that the payment of such interest shall be legally
enforceable), from the dates such amounts are due until they are paid or made
available for payment, and such interest shall be payable on demand. 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 Debt Security (or one or more Predecessor Securities) is registered at
the close of business on the Regular Record Date for such interest. Any such
interest not so punctually paid or duly provided for will 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 Debt 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 Debt 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
Debt Securities of this series may be listed, and upon such notice as may be
required by such exchange, all as more fully provided in such Indenture.

      Payment of the principal of and interest on this Debt Security will be
made at the office or agency of the Company maintained for that purpose in the
City of New York, New York (or, if the Company does not maintain such office or
agency, at the corporate trust office of the Trustee in the City of New York or
if the Trustee does not maintain an office in the City of New York, at the
office of a Paying Agent in the City of New York), 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 debt; provided, however, that at the option of the
Company payments of principal or interest may be made by check mailed to the
address of the Person entitled thereto as such address shall appear in the
Security Register.

      "Regular Record Date" means, with respect to any Interest Payment Date,
December 15 or June 15, as the case may be, immediately preceding such Interest
Payment Date.

<PAGE>

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

<PAGE>

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

Dated:                                 BERKSHIRE HATHAWAY FINANCE
                                       CORPORATION

                                       By: _________________________
                                       Name: Marc D. Hamburg
                                       Title: President

Attest:

______________________
Name: Jerry W. Hufton
Title: Secretary

<PAGE>

                           [REVERSE OF DEBT SECURITY]

            This Debt Security is one of a duly authorized series of notes of
the Company (herein called the "Debt Securities"), issued and to be issued in
one or more series under an Indenture, dated as of December 22, 2003 (herein
called the "Base Indenture", and as supplemented by (i) the Officers'
Certificate, dated as of December 22, 2003, (ii) the Officers' Certificate,
dated as of May 7, 2004, (iii) the Officers' Certificate, dated as of July 19,
2004, (iv) the Officers' Certificate, dated as of September 20, 2004 and (v) the
Officers' Certificate, dated as of [******], together with the Base Indenture,
called the "Indenture"), among the Company, as issuer, Berkshire Hathaway Inc.,
as guarantor (herein the "Guarantor" which term includes any successor Guarantor
under the Indenture) and J.P. Morgan Trust Company, National Association, as
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 Guarantor, the Trustee and the Holders of the
Debt Securities and of the terms upon which the Debt Securities are, and are to
be, authenticated and delivered. This Debt Security is one of the series of Debt
Securities, which series consists of both 3.40% Senior Notes due 2007 and 5.10%
Senior Notes due 2014.

            This Debt Security does not have the benefit of any sinking fund
obligation.

            The Indenture contains provisions for defeasance at any time of the
entire Indebtedness of this Debt Security or of certain restrictive covenants
and Events of Default with respect to this Debt Security, in each case upon
compliance with certain conditions set forth in the Indenture.

            If an Event of Default with respect to the Debt Securities of this
series shall occur and be continuing, the principal of the Debt Securities of
this series may be declared due and payable in the manner and with the effect
provided 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/or the Guarantor and the rights of the Holders of the Debt
Securities and/or the Guarantees of each series to be affected under the
Indenture at any time by the Company, the Guarantor and the Trustee with the
consent of the Holders of a majority in principal amount of the Debt 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 Debt Securities of each series at the time Outstanding, on behalf
of the Holders of all Debt Securities of such series, to waive compliance by the
Company and/or the Guarantor 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 Debt Security shall be conclusive and
binding upon such Holder and upon all future Holders of this Debt Security and
of any Debt 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 Debt Security.

            As provided in and subject to the provisions of the Indenture, the
Holder of this Debt 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 Debt Securities of this series, the Holders of not less than
25% in principal amount of the Debt 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 indemnity or security reasonably satisfactory to it, and the Trustee
shall not have received

<PAGE>

from the Holders of a majority in principal amount of Debt 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 Debt Security for the enforcement of
any payment of principal hereof or any premium or interest hereon on or after
the respective due dates expressed herein.

            No reference herein to the Indenture and no provision of this Debt
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 any
interest on this Debt 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 Debt Security is registrable in the
Security Register, upon surrender of this Debt Security for registration of
transfer at the office or agency of the Company in any place where the principal
of and any premium and interest on this Debt Security are payable, 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
its attorney duly authorized in writing, and thereupon one or more new Debt
Securities of this series and of like tenor, of authorized denominations and for
the same aggregate principal amount, will be issued to the designated transferee
or transferees.

            The Indenture and this Debt Security are governed by the laws of the
State of New York, without regard to conflicts of laws provisions thereof.

            The Debt Securities of this series are issuable in registered form
without coupons in minimum denominations of $2,000 and integral multiples of
$1,000 in excess thereof. As provided in the Indenture and subject to certain
limitations therein set forth, Debt Securities of this series are exchangeable
for a like aggregate principal amount of Debt Securities of this series and of
like tenor of a different authorized denomination, 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.

            Prior to due presentment of this Debt Security for registration of
transfer, the Company, the Guarantor, the Trustee and any agent thereof may
treat the Person in whose name this Debt Security is registered as the owner
hereof for all purposes, whether or not this Debt Security be overdue, and none
of the Company, the Guarantor, the Trustee or any such agent shall be affected
by notice to the contrary.

            All terms used in this Debt Security which are not defined herein
and are defined in the Indenture shall have the meanings assigned to them in the
Indenture.

<PAGE>

                                  GUARANTEE OF
                             BERKSHIRE HATHAWAY INC.

      FOR VALUE RECEIVED, Berkshire Hathaway Inc., a Delaware corporation (the
"Guarantor"), hereby absolutely, unconditionally and irrevocably guarantees to
the holders (the "Holders") of any security authenticated and delivered (each a
"Security") by J.P. Morgan Trust Company, National Association, as trustee (the
"Trustee") under that certain Indenture, dated as of December 22, 2003 (the
"Indenture"), among the Trustee, the Guarantor and Berkshire Hathaway Finance
Corporation, a Delaware corporation ("Issuer"), the full and prompt payment when
due (whether at stated maturity, by acceleration or otherwise) of all present
and future payment obligations of the Issuer pursuant to the terms of such
Security and/or the Indenture, whether direct or indirect, absolute or
contingent, and whether for principal, interest, fees, expenses, indemnification
or otherwise (collectively, the "Obligations"). Nothing herein shall be deemed
to guarantee any obligation of the Issuer other than the Obligations. Nothing
herein shall be deemed to guarantee any obligation of any person or entity other
than the Issuer.

      The Guarantor's obligations hereunder shall be unconditional and absolute,
and shall not be released, discharged or otherwise affected by (i) the
existence, validity, enforceability, perfection or extent of any collateral
therefor, (ii) any lack of validity or enforceability of any provision of the
Security or the Indenture, (iii) any liquidation, bankruptcy, insolvency,
reorganization or other similar proceeding affecting the Issuer or its assets,
or (iv) any other circumstance relating to the Obligations that might otherwise
constitute a legal or equitable discharge of, or defense to, the Guarantor. The
Guarantor agrees that the Holders and/or the Trustee may resort to the
Guarantor, as primary obligor and not merely as surety, for payment of any of
the Obligations whether or not the Holders or the Trustee shall have proceeded
against the Issuer or any other obligor principally or secondarily obligated
with respect to any of the Obligations. Neither the Holders nor the Trustee
shall be obligated to file any claim relating to any of the Obligations in the
event that the Issuer becomes subject to a bankruptcy, reorganization or similar
proceeding, and the failure of the Holders or the Trustee to so file shall not
affect the Guarantor's obligations hereunder. In the event that any payment to
the Holders by the Issuer in respect of any Obligations is rescinded or must
otherwise be returned for any reason whatsoever, the Guarantor shall remain
liable hereunder with respect to such Obligations as if such payment had not
been made.

      The Guarantor agrees that, subject to the Indenture, the Holders and/or
the Trustee may at any time and from time to time, either before or after the
maturity thereof, without notice to or further consent of the Guarantor, extend
the time of payment of, exchange or surrender any collateral for, or renew any
of the Obligations, and may also make any agreement with the Issuer or with any
other party to or person liable on any of the Obligations or interested therein,
for the extension, renewal, payment, compromise, discharge or release thereof,
in whole or in part, or for any modification of the terms thereof or of any
agreement between the Holders, the Trustee and the Issuer or any such other
party or person, and that none of the foregoing shall in any way impair or
affect this Guarantee. The Guarantor hereby unconditionally and irrevocably
waives, to the fullest extent permitted by law, (a) notice of the acceptance of
this Guarantee and of the Obligations, presentment, demand for payment, notice
of dishonor and protest, (b) any requirement that any Holder exhaust any right
or take any action against the Issuer, and (c) any right to revoke this
Guarantee.

<PAGE>

      The Guarantor agrees to pay on demand all fees and out-of-pocket expenses
incurred by the Holders or the Trustee in any way relating to the enforcement or
protection of the rights of the Holders and/or the Trustee hereunder.

      Upon payment of any of the Obligations, the Guarantor shall be subrogated
to the rights of the Holders and/or the Trustee against the Issuer with respect
to such Obligations, and the Holders and the Trustee agree to take such steps,
at the Guarantor's expense, as the Guarantor may reasonably request to implement
such subrogation; provided, however, that the Guarantor shall not be entitled to
enforce, or to receive any payments arising out of or based upon, such right of
subrogation during any period in which any amount payable by the Issuer under
the Security or the Indenture is overdue or unpaid.

      No failure on the part of the Holders or the Trustee to exercise, and no
delay in exercising, any right, remedy or power hereunder shall operate as a
waiver thereof, nor shall any single or partial exercise by the Holders or the
Trustee of any right, remedy or power hereunder preclude any other or future
exercise of any right, remedy or power. Each and every right, remedy and power
hereby granted to the Holders or the Trustee or allowed any of them by law or
other agreement shall be cumulative and not exclusive of any other, and may be
exercised by the Holders or the Trustee at any time or from time to time.

      The Guarantor hereby represents and warrants that:

(a)   the Guarantor is duly organized, validly existing and in good standing as
a corporation under the laws of the State of Delaware and has full corporate
power to execute, deliver and perform this Guarantee;

(b)   the execution, delivery and performance of this Guarantee have been and
remain duly authorized by all necessary corporate action and do not contravene
any provision of the Guarantor's certificate of incorporation or by-laws, as
amended to date, or any law, regulation, rule, decree, order, judgment or
contractual restriction binding on the Guarantor or its assets;

(c)   all consents, licenses, clearances, authorizations and approvals of, and
registrations and declarations with, any governmental authority or regulatory
body necessary for the due execution, delivery and performance of this Guarantee
have been obtained and remain in full force and effect and all conditions
thereof have been duly complied with, and no other action by, and no notice to
or filing with, any governmental authority or regulatory body is required in
connection with the execution, delivery or performance of this Guarantee;

(d)   this Guarantee constitutes a legal, valid and binding obligation of the
Guarantor enforceable against the Guarantor in accordance with its terms,
subject to bankruptcy, insolvency, reorganization, moratorium and other laws of
general applicability relating to or affecting creditors' rights and to general
equity principles; and

(e)   there are no actions, suits or arbitration proceedings pending or, to the
knowledge of the Guarantor, threatened against it, at law or in equity, which,
individually or in the aggregate, if adversely determined, would materially
adversely affect the financial condition of the Guarantor or materially impair
its ability to perform its obligations under this Guarantee.

      The Guarantor may not assign its obligations hereunder to any person
(except as permitted by the Indenture) without the prior written consent of the
Holders or the Trustee.

<PAGE>

      All payments by the Guarantor to the Holders or the Trustee shall be made
in accordance with the provisions of the Indenture and the Security; provided,
however, that payment of any fees or expenses pursuant to the fourth paragraph
hereof shall be made by wire transfer of immediately available funds to an
account at a commercial bank in the United States specified to the Guarantor at
least ten (10) days in advance of any demand for payment by the Holders or the
Trustee.

      All notices or demands on the Guarantor shall be deemed effective when
received, shall be in writing and shall be delivered by hand or by registered
mail, or by facsimile transmission promptly confirmed by registered mail,
addressed to the Guarantor at:

           Berkshire Hathaway Inc.
           1440 Kiewit Plaza
           Omaha, NE 68131
           Attention: Chief Financial Officer
           Facsimile: (402) 346-3375

or to such other addresses or facsimile numbers as the Guarantor shall have
notified the Holders or the Trustee in a written notice delivered in accordance
with the Indenture.

      This Guarantee shall remain in full force and effect and shall be binding
on the Guarantor, its successors and assigns until all of the Obligations have
been satisfied in full.

      This Guarantee shall be governed by, and construed in accordance with, the
laws of the State of New York applicable to contracts made and to be performed
solely within such State.

      No amendment or waiver of any provision of this Guarantee shall in any
event be effective unless the same shall be in writing and signed by the Trustee
and the Guarantor.

      If for any reason any provision or provisions hereof are determined to be
invalid and contrary to any existing or future law, such invalidity shall not,
to the fullest extent permitted by law, impair the operation of or effect of
those portions of this Guarantee that are valid.

      THE GUARANTOR WAIVES ANY RIGHT IT MAY HAVE TO A JURY TRIAL IN CONNECTION
WITH ANY ACTION, SUIT OR PROCEEDING ARISING OUT OF OR RELATED IN ANY WAY TO THIS
GUARANTEE.

<PAGE>

Dated:                                            BERKSHIRE HATHAWAY INC.

                                                  By:___________________________
                                                  Name:  Marc D. Hamburg
                                                  Title: Chief Financial Officer

<PAGE>

              SCHEDULE OF INCREASES OR DECREASES IN GLOBAL SECURITY

      The following increases or decreases in this Debt Security have been made:

<TABLE>
<CAPTION>
                    Amount of decrease in   Amount of increase in     Principal amount of this     Signature of authorized
                         principal              principal amount           Debt Security           signatory of Trustee or
                      amount of this            of this Debt               following such            Security Custodian
Date of exchange      Debt Security               Security              decrease or increase
----------------    ---------------------   ---------------------     ------------------------     -----------------------
<S>                 <C>                     <C>                       <C>                          <C>
</TABLE>

<PAGE>

                                   ASSIGNMENT

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

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

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

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

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

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

and irrevocably appoints _______ as agent to transfer this Debt Security on the
Security Register. The agent may substitute another to act for him or her.

     Dated:                   Signature:

                          Signature Guarantee:

   (Sign exactly as your name appears on the other side of this Debt Security)

            Signatures must be guaranteed by an "eligible guarantor institution"
meeting the requirements of the Security Registrar, which requirements include
membership or participation in the Security Transfer Agent Medallion Program
("STAMP") or such other "signature guarantee program" as may be determined by
the Security Registrar in addition to, or in substitution for, STAMP, all in
accordance with the Securities Exchange Act of 1934, as amended.