<PAGE>   1


                                                                     EXHIBIT 4.8

                            LIBERTY MEDIA CORPORATION

                                       AND

                              THE BANK OF NEW YORK

                                     Trustee

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

                          THIRD SUPPLEMENTAL INDENTURE

                          Dated as of February 2, 2000

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

                        Supplementing the Trust Indenture

                            Dated as of July 7, 1999

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

                $1,000,000,000 8-1/4% Senior Debentures due 2030


<PAGE>   2






         THIRD SUPPLEMENTAL INDENTURE, dated as of the 2nd day of February,
2000, between LIBERTY MEDIA CORPORATION, a corporation existing under the laws
of the State of Delaware (the "Company"), and The Bank of New York, a New York
banking corporation, having its principal corporate trust office in The City of
New York, New York, as trustee (the "Trustee");

         WHEREAS, the Company has heretofore executed and delivered to the
Trustee an Indenture dated as of July 7, 1999 (the "Original Indenture" and,
together with this Third Supplemental Indenture, the "Indenture") providing for
the issuance by the Company from time to time of its senior debt securities to
be issued in one or more series (in the Original Indenture and herein called the
"Securities");

         WHEREAS, the Company, in the exercise of the power and authority
conferred upon and reserved to it under the provisions of the Original Indenture
and pursuant to appropriate resolutions of the Board of Directors, has duly
determined to make, execute and deliver to the Trustee this Third Supplemental
Indenture to the Original Indenture in order to establish the form and terms of,
and to provide for the creation and issue of, a series of Securities designated
as the "8-1/4% Senior Debentures due 2030" under the Original Indenture in the
aggregate principal amount of $1,000,000,000;

         WHEREAS, Section 901 of the Original Indenture provides, among other
things, that the Company, when authorized by a Board Resolution, and the
Trustee, at any time and from time to time, without the consent of any Holders,
may enter into an indenture supplemental to the Original Indenture to establish
the terms of Securities of any series as permitted by Sections 201 and 301 of
the Original Indenture; and

         WHEREAS, all things necessary to make the Securities, when executed by
the Company and authenticated and delivered by the Trustee or any Authenticating
Agent and issued upon the terms and subject to the conditions hereinafter and in
the Indenture set forth against payment therefor, the valid, binding and legal
obligations of the Company and to make this Third Supplemental Indenture a
valid, binding and legal agreement of the Company, have been done;

NOW, THEREFORE, THIS THIRD SUPPLEMENTAL INDENTURE WITNESSETH that, in order to
establish the terms of a series of Securities designated as the "8-1/4% Senior
Debentures due 2030," and for and in consideration of the premises and of the
covenants contained in the Original Indenture and in this Third Supplemental
Indenture and for other good and valuable consideration the receipt and
sufficiency of which are hereby acknowledged, it is mutually covenanted and
agreed as follows:



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                                  ARTICLE ONE

                              DEFINITIONS AND OTHER
                        PROVISIONS OF GENERAL APPLICATION

         Section 101. Definitions.

         Each capitalized term that is used herein and is defined in the
Original Indenture shall have the meaning specified in the Original Indenture
unless such term is otherwise defined herein.

         "Cedel" shall mean Cedelbank.

         "Depository" shall have the meaning assigned to it in the Original
Indenture.

         "DTC" shall mean The Depository Trust Company.

         "Euroclear" shall mean the Euroclear System.

         "Initial Purchasers" shall mean Lehman Brothers Inc. and Salomon Smith
Barney Inc.

         "Interest Payment Date" shall have the meaning assigned to it in
Section 206.

         "Permanent Regulation S Security" shall have the meaning assigned to it
in Section 213(c).

         "Regulation S" shall mean Regulation S under the Securities Act.

         "Restricted Period" shall have the meaning assigned to it in Section
207.

         "Rule 144A" shall mean Rule 144A under the Securities Act.

         "Rule 144A Security" shall have the meaning assigned to it in Section
213(b).

         "Securities" shall mean the Company's 8-1/4% Senior Debentures due
2030.

         "Securities Act" shall mean the United States Securities Act of 1933,
as amended.

         "Temporary Regulation S Security" shall have the meaning assigned to it
in Section 213(c).

         Section 102. Section References.

         Each reference to a particular section set forth in this Third
Supplemental Indenture shall, unless the context otherwise requires, refer to
this Third Supplemental Indenture.



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                                  ARTICLE TWO

                        TITLE AND TERMS OF THE SECURITIES

         Section 201. Title of the Securities.

         The title of the Securities of the series established hereby is the
"8-1/4% Senior Debentures due 2030."

         Section 202. Amount and Denominations.

         The aggregate principal amount of the Securities which may be
authenticated and delivered under the Indenture is limited to $1,000,000,000,
except for Securities authenticated and delivered upon registration of transfer
of, or in exchange for, or in lieu of, other Securities of the same series
pursuant to Section 304, 305, 306, 904 or 1107 of the Original Indenture;
provided, however, that the Securities may be reopened, without the consent of
the Holders thereof, for issuance of additional Securities.

         Section 203. Registered Securities.

         The certificates for the Securities shall be Registered Securities and
shall be in substantially the form attached hereto as Exhibits A-1, A-2 and A-3,
and shall bear the legends as are inscribed thereon.

         Section 204. Issuance and Pricing.

         The Securities shall be issued and sold by the Company to the Initial
Purchasers, parties to the Purchase Agreement dated January 26, 2000 with the
Company, at a price equal to 98.324% of the principal amount thereof, and the
initial price to purchasers of the Securities from the Initial Purchasers shall
be 99.199% of the principal amount thereof, plus accrued interest, if any, from
February 2, 2000.

         Section 205. Stated Maturity.

         The Stated Maturity of the Securities on which the principal thereof is
due and payable shall be February 1, 2030.

         Section 206. Interest.

         The principal of the Securities shall bear interest from February 2,
2000 or from the most recent Interest Payment Date to which interest has been
paid or provided for, payable semiannually on February 1 and August 1 of each
year (each, an "Interest Payment Date"), commencing August 1, 2000, to the
Persons in whose names the Securities (or one or more Predecessor Securities)
are registered at the close of business on the January 15 or July 15 next
preceding such Interest Payment Date. Interest on the Securities shall be
computed on the basis of a 360-day year of twelve 30-day months.



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         Interest on the Securities will accrue at the rate of 8-1/4% per annum
until the principal thereof is paid or made available for payment.

         Section 207. Registration, Transfer and Exchange.

         The principal of and interest on the Securities shall be payable and
the Securities may be surrendered or presented for payment, the Securities may
be surrendered for registration of transfer or exchange, and notices and demands
to or upon the Company in respect of the Securities and the Indenture may be
served, at the office or agency of the Company maintained for such purposes in
The City of New York, State of New York from time to time, and the Company
hereby appoints the Trustee, acting through its office or agency in The City of
New York designated from time to time for such purpose, as its agent for the
foregoing purposes; provided, however, that at the option of the Company,
payment of interest on the Securities may be made by check mailed to the address
of the Persons entitled thereto, as such addresses shall appear in the Security
Register; and provided, further, that (subject to Section 1002 of the Indenture)
the Company may at any time remove the Trustee as its office or agency in The
City of New York designated for the foregoing purposes and may from time to time
designate one or more other offices or agencies for the foregoing purposes and
may from time to time rescind such designations. Notwithstanding the foregoing,
a Holder of $10 million or more in aggregate principal amount of certificated
Securities on a Regular Record Date shall be entitled to receive interest
payments on the next succeeding Interest Payment Date, other than an Interest
Payment Date that is also the date of Maturity, by wire transfer of immediately
available funds if appropriate wire transfer instructions have been received in
writing by the Trustee not less than 15 calendar days prior to the applicable
Interest Payment Date. Any wire transfer instructions received by the Trustee
will remain in effect until revoked by the Holder.

         Rule 144A Security to Temporary Regulation S Security. Prior to the
expiration of the "40-day restricted period" (within the meaning of Rule
903(c)(3) of Regulation S) (the "Restricted Period"), if a holder of a
beneficial interest in a Rule 144A Security deposited with the Depository wishes
at any time to exchange all or a portion of its interest in such Rule 144A
Security for an interest in the Temporary Regulation S Security, or to transfer
all or a portion of its interest in such Rule 144A Security to a Person who
wishes to take delivery thereof in the form of an interest in such Temporary
Regulation S Security, such holder may, subject to the rules and procedures of
the Depository and to the requirements set forth in the following sentence,
exchange or cause the exchange or transfer or cause the transfer of such
interest for an equivalent beneficial interest in such Temporary Regulation S
Security. Upon receipt by the Trustee, as transfer agent, at its office in The
City of New York of (1) instructions given in accordance with the Depository's
procedures from an agent member directing the Trustee to credit or cause to be
credited a beneficial interest in the Temporary Regulation S Security in an
amount equal to the beneficial interest in the Rule 144A Security to be
exchanged or transferred, (2) a written order given in accordance with the
Depository's procedures containing information regarding the Euroclear or Cedel
account to be credited with such increase and the name of such account and (3) a
certificate substantially in the form of Exhibit B hereto given by the holder of
such beneficial interest, the Trustee, as transfer agent, shall instruct the
Depository, its nominee, or the custodian for the Depository, as the case may
be, to reduce or reflect on its records a reduction of the Rule 144A Security by
the aggregate principal amount of the beneficial interest in such Rule 144A
Security to be so exchanged or transferred and the Trustee, as transfer agent,




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shall instruct the Depository, its nominee, or the custodian for the Depository,
as the case may be, concurrently with such reduction, to increase or reflect on
its records an increase of the principal amount of such Temporary Regulation S
Security by the aggregate principal amount of the beneficial interest in such
Rule 144A Security to be so exchanged or transferred, and to credit or cause to
be credited to the account of the Person specified in such instructions (who
shall be the agent member of Euroclear or Cedel, or both, as the case may be) a
beneficial interest in such Temporary Regulation S Security equal to the
reduction in the principal amount of such Rule 144A Security.

         Rule 144A Security to Permanent Regulation S Security. After the
expiration of the Restricted Period, if a holder of a beneficial interest in the
Rule 144A Security deposited with the Depository wishes at any time to exchange
all or a portion of its interest in such Rule 144A Security for an interest in
the Permanent Regulation S Security, or to transfer all or a portion of its
interest in such Rule 144A Security to a Person who wishes to take delivery
thereof in the form of an interest in such Permanent Regulation S Security, such
holder may, subject to the rules and procedures of the Depository and to the
requirements set forth in the following sentence, exchange or cause the exchange
or transfer or cause the transfer of such interest for an equivalent beneficial
interest in such Permanent Regulation S Security. Upon receipt by the Trustee,
as transfer agent, at its office in The City of New York of (1) instructions
given in accordance with the Depository's procedures from an agent member
directing the Trustee to credit or cause to be credited a beneficial interest in
the Permanent Regulation S Security in an amount equal to the beneficial
interest in the Rule 144A Security to be exchanged or transferred, (2) a written
order given in accordance with the Depository's procedures containing
information regarding the Euroclear or Cedel account to be credited with such
increase and (3) a certificate substantially in the form of Exhibit C hereto
given by the holder of such beneficial interest, the Trustee, as transfer agent,
shall instruct the Depository, its nominee, or the custodian for the Depository,
as the case may be, to reduce or reflect on its records a reduction of the Rule
144A Security by the aggregate principal amount of the beneficial interest in
such Rule 144A Security to be so exchanged or transferred and the Trustee, as
transfer agent, shall instruct the Depository, its nominee, or the custodian for
the Depository, as the case may be, concurrently with such reduction, to
increase or reflect on its records an increase of the principal amount of such
Permanent Regulation S Security by the aggregate principal amount of the
beneficial interest in such Rule 144A Security to be so exchanged or
transferred, and to credit or cause to be credited to the account of the Person
specified in such instructions (who shall be the agent member of Euroclear or
Cedel, or both, as the case may be) a beneficial interest in such Permanent
Regulation S Security equal to the reduction in the principal amount of such
Rule 144A Security.

         Regulation S Security to Rule 144A Security. If a holder of a
beneficial interest in the Temporary Regulation S Security or the Permanent
Regulation S Security which is deposited with the Depository wishes at any time
to exchange its interest for an interest in the Rule 144A Security, or to
transfer its interest in such Temporary Regulation S Security or Permanent
Regulation S Security to a Person who wishes to take delivery thereof in the
form of an interest in such Rule 144A Security, such holder may, subject to the
rules and procedures of Euroclear or Cedel and the Depository, as the case may
be, and to the requirements set forth in the following sentence, exchange or
cause the exchange or transfer or cause the transfer of such interest for an
equivalent beneficial interest in such Rule 144A Security. Upon receipt by the
Trustee, as transfer agent, at its offices in The City of New York of (1)
instructions from Euroclear or Cedel



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<PAGE>   7

or the Depository, as the case may be, directing the Trustee, as transfer agent,
to credit or cause to be credited a beneficial interest in the Rule 144A
Security in an amount equal to the beneficial interest in the Temporary
Regulation S Security or the Permanent Regulation S Security to be exchanged or
transferred, such instructions to contain information regarding the agent
member's account with the Depository to be credited with such increase, and (2)
with respect to an exchange or transfer of an interest in the Temporary
Regulation S Security (but not the Permanent Regulation S Security) for an
interest in the Rule 144A Security, a certificate substantially in the form of
Exhibit D hereto given by the holder of such beneficial interest, the Trustee,
as transfer agent, shall instruct the Depository, its nominee, or the custodian
for the Depository, as the case may be, to reduce or reflect on its records a
reduction of the Temporary Regulation S Security or such Permanent Regulation S
Security, as the case may be, by the aggregate principal amount of the
beneficial interest in such Temporary Regulation S Security or such Permanent
Regulation S Security to be exchanged or transferred, and the Trustee, as
transfer agent, shall instruct the Depository, its nominee, or the custodian for
the Depository, as the case may be, concurrently with such reduction, to
increase or reflect on its records an increase of the principal amount of such
Rule 144A Security by the aggregate principal amount of the beneficial interest
in such Permanent Regulation S Security or such Temporary Regulation S Security,
as the case may be, to be so exchanged or transferred, and to credit or cause to
be credited to the account of the Person specified in such instructions a
beneficial interest in such Rule 144A Security equal to the reduction in the
principal amount of such Permanent Regulation S Security or such Temporary
Regulation S Security, as the case may be.

         Temporary Regulation S Security to Permanent Regulation S Security.
After the expiration of the Restricted Period, interests in a Temporary
Regulation S Security as to which the Trustee has received from Euroclear or
Cedel, as the case may be, a certificate substantially in the form of Exhibit E
hereto to the effect that Euroclear or Cedel, as applicable, has received a
certificate substantially in the form of Exhibit F hereto from the holder of a
beneficial interest in such Temporary Regulation S Security, will be exchanged,
on and after the Restricted Period, for interests in the Permanent Regulation S
Security. The Trustee shall effect such exchange by delivering to the Depository
for credit to the respective accounts of the holders of Securities represented
by a beneficial interest in the Temporary Regulation S Global Security, a duly
executed and authenticated Permanent Regulation S Security, representing the
principal amount of interests in the Temporary Regulation S Security initially
exchanged for interests in the Permanent Regulation S Security. The delivery to
the Trustee by Euroclear or Cedel of the certificate or certificates referred to
above may be relied upon by the Company and the Trustee as conclusive evidence
that the certificate or certificates referred to therein has or have been
delivered to Euroclear or Cedel pursuant to the terms of this Third Supplemental
Indenture and the Temporary Regulation S Security. Upon any exchange of
interests in a Temporary Regulation S Security for interests in a Permanent
Regulation S Security, the Trustee shall endorse the Temporary Regulation S
Security to reflect the reduction in the principal amount represented thereby by
the amount so exchanged and shall endorse the Permanent Regulation S Security to
reflect the corresponding increase in the amount represented thereby. Until so
exchanged in full and except as provided therein, the Temporary Regulation S
Security, and the Securities evidenced thereby, shall in all respects be
entitled to the same benefits under the Indenture as the Permanent Regulation S
Security, the Rule 144A Security and the Restricted Certificated Securities
authenticated and delivered hereunder.



                                       7
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         Section 208. Redemption of the Securities.

         The Securities may not be redeemed by the Company prior to their Stated
Maturity.

         Section 209. Denominations.

         The Securities shall be issued in denominations of $1,000 and integral
multiples in excess thereof.

         Section 210. Currency.

         The interest and principal on the Securities shall be payable only in
Dollars.

         Section 211. Applicability of Certain Indenture Provisions.

         Sections 402 (including, without limitation, Sections 402(2) and
402(3)), 403, 1005, 1006 and 1007 of the Indenture shall apply to the
Securities.

         Section 212. Security Registrar and Paying Agent.

         The Trustee shall be Security Registrar and the initial Paying Agent
and initial transfer agent for the Securities (subject to the Company's right
(subject to Section 1002 of the Indenture) to remove the Trustee as such Paying
Agent and/or transfer agent with respect to the Securities and, from time to
time, to designate one or more co-registrars and one or more other Paying Agents
and transfer agents and to rescind from time to time any such designations), and
The City of New York is designated as a Place of Payment for the Securities.

         Section 213. Global Securities.

         (a) Securities may be issued in whole or in part in the form of one or
more temporary or permanent global Securities. The initial Depository for the
global Securities shall be DTC, and the depositary arrangements shall be those
employed by whoever shall be the Depositary with respect to the Securities from
time to time.

         (b) Rule 144A Securities. Securities initially offered and sold in
reliance on Rule 144A to Qualified Institutional Buyers (as such term is defined
in Rule 144A) shall be issued in the form of permanent Global Securities in
definitive fully registered form without interest coupons, substantially in the
form of Exhibit A-1 (a "Rule 144A Security"). Each Rule 144A Security shall be
deposited on behalf of the purchasers of the Securities represented thereby with
the custodian for the Depositary, and registered in the name of a nominee of the
Depositary, duly executed by the Company and authenticated by the Trustee as
provided in the Original Indenture. The aggregate principal amount of a Rule
144A Security may from time to time be increased or decreased by adjustments
made on the records of the custodian for the Depositary or the Depositary or its
nominee, as the case may be.

         (c) Temporary Regulation S Securities; Permanent Regulation S
Securities. Securities initially offered and sold in reliance on Regulation S
shall be issued in the form of temporary Global Securities in definitive fully
registered form without interest coupons, substantially in the




                                       8
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form of Exhibit A-2 (a "Temporary Regulation S Security"). Each Temporary
Regulation S Security shall be deposited on behalf of the purchasers of the
Securities represented thereby with the custodian for the Depositary, and
registered in the name of a nominee of the Depositary, duly executed by the
Company and authenticated by the Trustee as provided herein, for credit to their
respective accounts (or to such other accounts as they may direct) at Euroclear
or Cedel. After the expiration of the Restricted Period, each Temporary
Regulation S Security will be exchanged for a permanent Global Security,
substantially in the form of Exhibit A-3 (a "Permanent Regulation S Security").
Until the expiration of the Restricted Period, interests in a Temporary
Regulation S Security may only be held by agent members of Euroclear and Cedel.
During the Restricted Period, interests in a Temporary Regulation S Security may
be exchanged for interests in a Rule 144A Security. The aggregate principal
amount of a Temporary Regulation S Security and a Permanent Regulation S
Security may from time to time be increased or decreased by adjustments made on
the records of the custodian for the Depositary or the Depositary or its
nominee, as the case may be, as provided herein.

         The provisions of the "Operating Procedures of the Euroclear System"
and the "Terms and Conditions Governing Use of Euroclear" and the "Management
Regulations" and "Instructions to Participants" of Cedel, respectively, shall be
applicable to any Global Security insofar as interests in such Global Security
are held by the agent members of Euroclear or Cedel. Account holders or
participants in Euroclear and Cedel shall have no rights under the Indenture
with respect to such Global Security, and the Depositary or its nominee may be
treated by the Company, the Trustee, and any agent of the Company or the Trustee
as the owner of such Global Security for all purposes whatsoever.
Notwithstanding the foregoing, nothing herein shall prevent the Company, the
Trustee, or any agent of the Company or the Trustee from giving effect to any
written certification, proxy or other authorization furnished by the Depositary
or impair, as between DTC and its agent members, the operation of customary
practices governing the exercise of the rights of a holder of any Security.

         Section 214. Payments on Temporary Regulation S Security.

         Prior to expiration of the Restricted Period, payments (if any) on the
Temporary Regulation S Securities will only be paid to the Holder thereof to the
extent that there is presented by Cedel or Euroclear to the Trustee a
certificate, substantially in the form set out in Exhibit E hereto, to the
effect that it has received from or in respect of a beneficial owner of an
interest in such Temporary Regulation S Securities (as shown by its records) a
certificate substantially in the form of Exhibit F hereto. After the Restricted
Period, the Holders of Temporary Regulation S Securities will not be entitled to
receive any payment thereon.

         Section 215. Sinking Fund.

         The Securities shall not be subject to any sinking fund or similar
provision and shall not be redeemable at the option of the holder thereof.

         Section 216. Conversion.

         The Securities shall not be convertible into Common Stock and shall not
be exchangeable for any other securities.



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                                  ARTICLE THREE

                            MISCELLANEOUS PROVISIONS

         The Trustee makes no undertaking or representations in respect of, and
shall not be responsible in any manner whatsoever for and in respect of, the
validity or sufficiency of this Third Supplemental Indenture or the proper
authorization or the due execution hereof by the Company or for or in respect of
the recitals and statements contained herein, all of which recitals and
statements are made solely by the Company.

         Except as expressly amended hereby, the Original Indenture shall
continue in full force and effect in accordance with the provisions thereof and
the Original Indenture is in all respects hereby ratified and confirmed. This
Third Supplemental Indenture and all its provisions shall be deemed a part of
the Original Indenture in the manner and to the extent herein and therein
provided.

         This Third Supplemental Indenture 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.

         This Third Supplemental Indenture may be executed in any number of
counterparts, each of which so executed shall be deemed to be an original, but
all such counterparts shall together constitute but one and the same instrument.




                                       10
<PAGE>   11





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

                           LIBERTY MEDIA CORPORATION



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


                           THE BANK OF NEW YORK, as Trustee



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




                                       11
<PAGE>   12








               EXHIBITS A-1 THROUGH A-4 ARE INTENTIONALLY OMITTED.



                                      A-1

<PAGE>   13



                                    Exhibit B


                          FORM OF TRANSFER CERTIFICATE
                FOR EXCHANGE OR TRANSFER FROM RULE 144A SECURITY
                       TO TEMPORARY REGULATION S SECURITY



The Bank of New York
101 Barclay Street
Floor 21 West
New York, New York  10286

                  Re:      Liberty Media Corporation
                           [$1,000,000,000 8-1/4% Senior Debentures due 2030
                           (the "Securities")]

         Reference is hereby made to the Indenture dated as of July 7, 1999,
between THE BANK OF NEW YORK (the "Trustee") and LIBERTY MEDIA CORPORATION (the
"Company") (as supplemented by the Third Supplemental Indenture, dated as of
February 2, 2000, between the Company and the Trustee, the "Indenture").
Capitalized terms not defined in this Certificate shall have the meanings given
to them in the Indenture.

         This Certificate relates to ______________ principal amount of
Securities represented by a beneficial interest in the Rule 144A Security (CUSIP
No.____) held through the Depository by or on behalf of [transferor] as
beneficial owner (the "Transferor"). The Transferor has requested an exchange or
transfer of its beneficial interest for an interest in the Temporary Regulation
S Security (CUSIP (CINS) No._____) to be held with [Euroclear] [Cedel] (ISIN
Code _____) (Common Code _____) through the Depository.

         In connection with such request and in respect of such Securities, the
Transferor does hereby certify that such exchange or transfer has been effected
in accordance with the transfer restrictions set forth in the Securities and
pursuant to and in accordance with Rule 903 or Rule 904 (as applicable) of
Regulation S under the Securities Act, and accordingly the Transferor does
hereby certify that:

         (1)      the offer of the Securities was not made to a person in the
                  United States;

         (2)      either:  (A)      at the time the buy order was originated,
                                    the transferee was outside the United States
                                    or the Transferor and any person acting on
                                    its behalf reasonably believed that the
                                    transferee was outside the United States, or

                           (B)      the transaction was executed in, on or
                                    through the facilities of, a designated
                                    offshore securities market and neither the
                                    Transferor nor any person acting on its
                                    behalf knows that the transaction was
                                    prearranged with a buyer in the United
                                    States;

                                       B-1
<PAGE>   14

         (3)      no directed selling efforts have been made in contravention of
                  the requirements of Rule 903(b) or 904(b) of Regulation S, as
                  applicable;

         (4)      the transaction is not part of a plan or scheme to evade the
                  registration requirements of the Securities Act; and

         (5)      upon completion of the transaction, the beneficial interest
                  being transferred as described above is to be held with the
                  Depository through Euroclear or Cedel or both (Common Code
                  ____ (ISIN Code _____)).

         This Certificate and the statements contained herein are made for your
benefit and the benefit of the Company and the initial purchasers of the
Securities being exchanged or transferred. Terms used in this Certificate and
not otherwise defined in the Indenture have the meanings set forth in Regulation
S under the Securities Act.

                              [Insert Name of Transferor]



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


Dated:
        --------------------------------

cc:      Liberty Media Corporation


                                      B-2
<PAGE>   15




                                    Exhibit C


                    FORM OF TRANSFER CERTIFICATE FOR TRANSFER
                       OR EXCHANGE FROM RULE 144A SECURITY
                       TO PERMANENT REGULATION S SECURITY


The Bank of New York
101 Barclay Street
Floor 21 West
New York, New York  10286

                  Re:      Liberty Media Corporation
                           [$1,000,000,000 8-1/4% Senior Debentures due 2030
                           (the "Securities")]


         Reference is hereby made to the Indenture dated as of July 7, 1999,
between THE BANK OF NEW YORK (the "Trustee") and LIBERTY MEDIA CORPORATION (the
"Company") (as supplemented by the Third Supplemental Indenture, dated as of
February 2, 2000, between the Company and the Trustee, the "Indenture").
Capitalized terms not defined in this Certificate shall have the meanings given
to them in the Indenture.

         This Certificate relates to ______________ principal amount of
Securities represented by a beneficial interest in the Rule 144A Security (CUSIP
No.____) held through the Depository by or on behalf of [transferor] as
beneficial owner (the "Transferor"). The Transferor has requested an exchange or
transfer of its interest for an interest in the Permanent Regulation S Security
(CUSIP (CINS) No. [____]) to be held by [Euroclear][Cedel] (ISIN Code _______)
(Common Code) through the Depositary.

         In connection with such request and in respect of such Securities, the
Transferor does hereby certify that such exchange or transfer has been effected
in accordance with the transfer restrictions set forth in the Securities and
that, with respect to transfers made in reliance on Regulation S under the
Securities Act:

         (1)      the offer of the Securities was not made to a person in the
                  United States;

         (2)      either:  (A)      at the time the buy order was originated,
                                    the transferee was outside the United States
                                    or the Transferor and any person acting on
                                    its behalf reasonably believed that the
                                    transferee was outside the United States, or

                           (B)      the transaction was executed in, on or
                                    through the facilities of, a designated
                                    offshore securities market and neither the
                                    Transferor nor any person acting on its
                                    behalf knows that the transaction was
                                    pre-arranged with a buyer in the United
                                    States;

         (3)      no directed selling efforts have been made in contravention of
                  the requirements of Rule 903(b) or 904(b) of Regulation S, as
                  applicable; and

                                      C-1
<PAGE>   16

         (4)      the transaction is not part of a plan or scheme to evade the
                  registration requirements of the Securities Act.

         This Certificate and the statements contained herein are made for your
benefit and the benefit of the Company and the initial purchasers of the
Securities being exchanged or transferred. Terms used in this Certificate and
not otherwise defined in the Indenture have the meanings set forth in Regulation
S under the Securities Act.

                                 [Insert Name of Transferor]



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


Dated:
        --------------------------

cc:      Liberty Media Corporation



                                      C-2
<PAGE>   17





                                    Exhibit D


                  FORM OF TRANSFER CERTIFICATE FOR TRANSFER OR
                  EXCHANGE FROM TEMPORARY REGULATION S SECURITY
                              TO RULE 144A SECURITY


The Bank of New York
101 Barclay Street
Floor 21 West
New York, New York  10286

                  Re:      Liberty Media Corporation
                           [$1,000,000,000 8-1/4% Senior Debentures due 2030
                           (the "Securities")]

         Reference is hereby made to the Indenture dated as of July 7, 1999
between THE BANK OF NEW YORK (the "Trustee") and LIBERTY MEDIA CORPORATION (the
"Company") (as supplemented by the Third Supplemental Indenture, dated as of
February 2, 2000, between the Company and the Trustee, the "Indenture").
Capitalized terms not defined in this Certificate shall have the meanings given
to them in the Indenture.

         This Certificate relates to ______________________________________
principal amount of Securities which are held in the form of the Temporary
Regulation S Security (CUSIP No. ___) with [Euroclear/Cedel] (ISIN Code [___])
(Common Code [___]) through the Depository by or on behalf of transferor as
beneficial owner (the "Transferor"). The Transferor has requested an exchange or
transfer of its interest in the Securities for an interest in the Rule 144A
Security (CUSIP NO. [___]).

         In connection with such request, and in respect of such Securities, the
Transferor does hereby certify that such transfer is being effected in
accordance with the transfer restrictions set forth in the Indenture and
pursuant to and in accordance with Rule 144A under the United States Securities
Act of 1933, as amended (the "Securities Act"), to a transferee that the
Transferor reasonably believes is purchasing the Securities for its own account
or an account with respect to which the transferee exercises sole investment
discretion and the transferee and any such account is a "qualified institutional
buyer" within the meaning of Rule 144A, in each case in a transaction meeting
the requirements of Rule 144A and in accordance with any applicable securities
laws of any state of the United States or any other jurisdiction.

         This Certificate and the statements contained herein are made for your
benefit and the benefit of the Company and the initial purchasers of the
Securities being transferred.

                               [Insert Name of Transferor]


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

Dated:
      ----------------------------

cc:      Liberty Media Corporation


                                      D-1

<PAGE>   18




                                    Exhibit E


                       FORM OF CLEARING SYSTEM CERTIFICATE


                  Re:      Liberty Media Corporation
                           [$1,000,000,000 8-1/4% Senior Debentures due 2030
                           (the "Securities")]


         Reference is hereby made to the Indenture dated as of July 7, 1999
between THE BANK OF NEW YORK (the "Trustee") and LIBERTY MEDIA CORPORATION (the
"Company") (as supplemented by the Third Supplemental Indenture, dated as of
February 2, 2000, between the Company and the Trustee, the "Indenture").
Capitalized terms not defined in this Certificate shall have the meanings given
to them in the Indenture.

         This is to certify that, based solely on certifications we have
received in writing, by tested telex or by electronic transmission from member
organizations appearing in our records as persons being entitled to a portion of
the principal amount set forth below (our "Member Organizations") substantially
to the effect set forth in the Indenture, as of the date hereof,
$_________________ aggregate principal amount of Securities represented by such
Temporary Regulation S Global Security is owned by (a) non-U.S. Persons or (b)
U.S. Persons who purchased such Securities in transactions that did not require
registration under the United States Securities Act of 1933, as amended (the
"Securities Act"). As used in this paragraph, the term "U.S. Person" has the
meaning given to it by Regulation S under the Securities Act.(1)

         We further certify (i) that we are not making available herewith for
payment of interest any portion of a Temporary Regulation S Global Security
excepted in such certifications and (ii) that as of the date hereof we have not
received any notification from any of our Member Organizations to the effect
that the statements made by such Member Organizations with respect to any
portion of a Temporary Regulation S Global Security submitted herewith for
payment of interest are no longer true and cannot be relied upon as the date
hereof.

         We understand that this certification is required in connection with
certain securities laws of the United States. In connection therewith, if
administrative or legal proceedings are commenced or threatened in connection
with which this certification is or would be relevant, we irrevocably authorize
you to produce this certification to any interested party in such proceedings.

                                             Yours faithfully,


--------
     (1)  Note: Unless Morgan Guaranty Brussels and Cedelbank are otherwise
          informed by the Initial Purchasers or the Trustee, the Standard
          Long-Form Certification set out in the Operating Procedures of
          Euroclear will be deemed to meet the requirements of this sentence.



                                      E-1
<PAGE>   19




                                       [MORGAN GUARANTY TRUST COMPANY OF
                                       NEW YORK, Brussels office, as operator of
                                       the Euroclear System]
                                       or
                                       [CEDELBANK]



                                       By:
                                          --------------------------------------


Dated:                        (2)
     ------------------------







---------------------
     (2)  Not earlier than 15 days prior to the relevant Interest Payment Date
          or Redemption Date, as the case may be.




                                      E-2
<PAGE>   20







                                    Exhibit F

                   FORM OF CERTIFICATE OF BENEFICIAL OWNERSHIP

                  Re:      Liberty Media Corporation
                           [$1,000,000,000 8-1/4% Senior Debentures due 2030
                           (the "Securities")]

         Reference is hereby made to the Indenture dated as of July 7, 1999
between THE BANK OF NEW YORK (the "Trustee") and LIBERTY MEDIA CORPORATION (the
"Company") (as supplemented by the Third Supplemental Indenture, dated as of
February 2, 2000, between the Company and the Trustee, the "Indenture").
Capitalized terms not defined in this Certificate shall have the meanings given
to them in the Indenture.

         This is to certify that as of the date hereof, and except as set forth
below, the above-captioned Securities held by you for our account are
beneficially owned by (a) non-U.S. person(s) or (b) U.S. person(s) who purchased
the Securities in transactions which did not require registration under the
Securities Act of 1933, as amended (the "Act"). As used in this paragraph, the
term "U.S. person" has the meaning given to it by Regulation S under the
Securities Act.

         As used herein, "United States" means the United States of America
(including the States and the District of Columbia); and its "possessions"
included Puerto Rico, the U.S. Virgin Islands, Guam, American Samoa, Wake Island
and the Northern Mariana Islands.

         We undertake to advise you promptly by tested telex or by electronic
transmission on or prior to the date on which you intend to submit your
certification relating to the Securities held by you for our account in
accordance with your operating procedures if any applicable statement herein is
not correct on such date, and in the absence of any such notification it may be
assumed that this certification applies as of such date.

         This certification excepts and does not relate to $____________________
of such interest in the above Securities in respect of which we are not able to
certify and as to which we understand exchange and delivery of definitive
Securities (or, if relevant, exercise of any rights or collection of any
interest) cannot be made until we do so certify.



                                      F-1
<PAGE>   21



         We understand that this certification is required in connection with
certain securities laws of the United States. In connection therewith, if
administrative or legal proceedings are commenced or threatened in connection
with which this certification is or would be relevant, we irrevocably authorize
you to produce this certification to any interested party in such proceedings.

Date:                              (3)
     ------------------------------        By:
                                              ----------------------------------

         As, or as agent for, the beneficial owner(s) of the Securities to which
this certificate relates.




-----------------------
     (3)  Not earlier than 15 days prior to the certification event to which the
          certification relates.


                                      F-2