Document:

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                                                                    EXHIBIT 10.3

                                EXCLUSIVE LICENSE
                           AND DISTRIBUTION AGREEMENT

                                     BETWEEN

                                  NOVAVAX, INC.

                                       AND

                           KING PHARMACEUTICALS, INC.

                                JANUARY 8, 2001

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                                TABLE OF CONTENTS

1.   DEFINITIONS........................................................1

2.   APPOINTMENT AND GRANT OF RIGHTS....................................1
   2.1    Appointment...................................................1
   2.2    Right to Promote Products.....................................2
   2.3    Trademark.....................................................2
   2.4    Ownership of Property Rights..................................3

3.   SUPPLY OF PRODUCTS.................................................4
   3.1    Manufacture and Supply of Products............................4
   3.2    Quarterly Forecasts; Purchase Orders..........................4
   3.3    Delivery of Products..........................................6
   3.4    Product Samples...............................................7
   3.5    Labeling and Packaging Costs..................................7

4.   CERTAIN REGULATORY MATTERS.........................................7
   4.1    Licenses......................................................7
   4.2    Regulatory Responsibility.....................................7
   4.3    Efficacy and Safety Information...............................8
   4.4    Notice of Adverse Events......................................8
   4.5    Recalls; Product Technical Complaints.........................9
   4.6    Notice of Government Inspections.............................10
   4.7    Government Inquiries.........................................10
   4.8    Medical Inquiries............................................10

5.   FEES AND EXPENSES.................................................10
   5.1    Purchase Price...............................................10
   5.2    Royalty Payment..............................................11

6.   INSPECTION AND WARRANTY OF PRODUCTS...............................12
   6.1    Inspection by KING...........................................12
   6.2    Disputes over Products.......................................12
   6.3    Replacement of Products that are not Acceptable Products.....12

7.   TERM AND TERMINATION..............................................13
   7.1    Term of Agreement............................................13
   7.2    Termination by NOVAVAX.......................................13
   7.3    Termination by KING..........................................14
   7.4    Effects of Termination.......................................14
   7.5    Actions Upon Termination.....................................15
   7.6    Survival.....................................................15
   7.7    Payments Upon Termination....................................15

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8.   CONFIDENTIAL INFORMATION..........................................16

9.   INDEMNIFICATION AND INSURANCE.....................................17
   9.1    Indemnification by KING......................................17
   9.2    Indemnification by NOVAVAX...................................18
   9.3    Claims Procedures............................................18
   9.4    Insurance....................................................19

10.  REPRESENTATIONS AND WARRANTIES....................................19
   10.1   By KING......................................................19
   10.2   By NOVAVAX...................................................19

11.  NOTICES...........................................................21

12.  MISCELLANEOUS PROVISIONS..........................................22
   12.1   Assignment; Change of Control................................22
   12.2   Governing Law................................................23
   12.3   Non-Waiver...................................................23
   12.4   Entire Agreement.............................................23
   12.5   Jurisdiction; Venue..........................................23
   12.6   Severability.................................................25
   12.7   Relationship of the Parties..................................25
   12.8   Public Announcements.........................................25
   12.9   Counterparts.................................................25
   12.10     Force Majeure.............................................26
   12.11     Interpretation............................................26
   12.12     Certain Expenses and Commissions..........................26
   12.13     Third Party Beneficiaries.................................26
   12.14     Covenant Not to Promote Competing Product.................26
   12.15     Headings..................................................27

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                  EXCLUSIVE LICENSE AND DISTRIBUTION AGREEMENT

                  THIS EXCLUSIVE LICENSE AND DISTRIBUTION AGREEMENT (this
"Agreement") is entered into and effective as of this 8th day of January, 2001
(the "Effective Date"), by and between KING PHARMACEUTICALS, INC., a Tennessee
corporation ("KING"), and NOVAVAX, INC., a Delaware corporation ("NOVAVAX").

                  WHEREAS, KING is engaged in the business of and has expertise
in, among other things, the promotion of pharmaceutical products to physicians
and health care practitioners who specialize in the practice of obstetrics or
gynecology or who frequently prescribe hormone replacement therapy products
("OB/GYN"), and has a field representative sales force focused on the OB/GYN
community;

                  WHEREAS, NOVAVAX owns or will own a patent or patents related
to the Products (as well as other intellectual property rights in the Products)
and expects to file with the FDA a New Drug Application for ESTRASORB(R);

                  WHEREAS, KING and NOVAVAX desire for NOVAVAX to manufacture or
have manufactured and supply KING with Products for promotion, distribution and
sale by KING in the Territory and NOVAVAX desires to manufacture or have
manufactured and supply KING with such Products on the terms and conditions set
forth herein.

                  NOW, THEREFORE, in consideration of the mutual covenants and
agreements set forth in this Agreement, and for other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the
parties hereto agree as follows:

1.       DEFINITIONS

                  Capitalized terms used herein without definition shall have
the respective meanings assigned thereto in Annex I attached hereto and
incorporated herein for all purposes of this Agreement (such definitions to be
equally applicable to both the singular and plural forms of the terms defined).
Unless otherwise specified, all references herein to "Sections" are to Sections
of this Agreement.

2.       APPOINTMENT AND GRANT OF RIGHTS

         2.1      APPOINTMENT.

                  NOVAVAX hereby appoints KING as its exclusive distributor of
the Products within the Territory during the Term of this Agreement, upon and

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subject to the terms and conditions set forth in this Agreement. The exclusivity
set forth in this Agreement shall be subject to any limitations provided under
applicable law, regulation or governmental guideline including, without
limitation, any published directive of the European Union.

         2.2      RIGHT TO PROMOTE PRODUCTS.

                  NOVAVAX hereby grants to KING and its Affiliates, the
exclusive right and license to promote, market, distribute and sell the Products
within the Territory during the Term of this Agreement, upon and subject to the
terms and conditions set forth in this Agreement. NOVAVAX shall not, nor shall
it permit its Affiliates, sublicensees, or any other party to, promote, market,
distribute or sell the Products within the Territory during the Term of this
Agreement. KING agrees to use Commercially Reasonable Efforts to obtain
regulatory authority to market and sell the Products within such countries in
the Territory as KING determines in its reasonable judgment is reasonable and,
after obtaining such regulatory authority, to use Commercially Reasonable
Efforts to promote, market, offer-to-sell and sell the Products in the
Territory, in such a manner as to effectuate KING's and NOVAVAX's purposes in
this Agreement.

         2.3      TRADEMARK.

                  (a)      Required Use and Compliance. NOVAVAX hereby grants to
KING a license to use the NOVAVAX Trademarks, which are set forth in Exhibit
2.3(a), for the duration of this Agreement solely for advertising, displaying,
marketing, promoting, using, offering-for-sale, selling, distributing, importing
and/or exporting the Products in accordance with this Agreement. KING shall
promote the Products only under the NOVAVAX Trademarks. KING shall not use any
trademark or servicemark other than the NOVAVAX Trademarks in promoting the
Products without the prior written approval of NOVAVAX. In connection with the
subject matter hereof, KING shall use the NOVAVAX Trademarks only in a manner
consistent with NOVAVAX's trademark usage guidelines (the "NOVAVAX Guidelines")
and shall not use any NOVAVAX Trademark in connection with any goods or products
other than the Products, notwithstanding that such goods or products are
dissimilar to the Products or have a different use. The parties shall develop
the NOVAVAX Guidelines as soon as practicable after the Effective Date. KING
shall use the NOVAVAX Trademarks only to the extent authorized herein. NOVAVAX
shall not use, nor permit any third party to use, the NOVAVAX Primary Brand
Trademarks or other NOVAVAX Trademarks used exclusively with respect to the
Products in the Territory during the Term of this Agreement.

                  (b)      Validity of Trademarks. KING acknowledges the
validity of NOVAVAX's right, title and interest in and to the NOVAVAX Trademarks
and KING shall not have, assert or acquire any right, title or interest in or to
any of

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the NOVAVAX Trademarks, except as otherwise explicitly provided in this
Agreement.

                  (c)      Notice of Infringement.

                           (i)      KING shall give NOVAVAX notice of any
infringement or threatened infringement of any NOVAVAX Trademarks used in
connection with this Agreement. Except as otherwise provided in Section
2.3(c)(ii) below, NOVAVAX shall determine in its sole discretion what action, if
any, to take in response to the infringement or threatened infringement of its
Trademark. In the event that NOVAVAX chooses to take enforcement action in
response to the infringement or threatened infringement of its Trademark, KING
shall reasonably cooperate in such enforcement; provided, however, that NOVAVAX
shall reimburse KING for reasonable expenses incurred by KING that are related
to such enforcement.

                           (ii)     NOVAVAX agrees to identify the primary brand
Trademarks of the Products (each a "Primary Brand Trademark"). Exhibit
2.3(c)(ii) sets forth the list of Primary Brand Trademarks for the Products as
of the Effective Date. As to each Primary Brand Trademark only, if NOVAVAX fails
to take enforcement action within ninety (90) days following notice thereof in
response to the infringement or threatened infringement of its Trademark in the
Territory, then KING shall have the right, in its sole discretion, to conduct
litigation or other enforcement proceedings to prevent such infringement at
NOVAVAX's expense. In such event, NOVAVAX shall reasonably cooperate in such
enforcement.

                           (iii)    The parties shall cooperate in good faith
with respect to all Trademark enforcement actions hereunder, and each party
shall notify the other party promptly of all substantive developments with
respect to such Trademark enforcement actions, including, without limitation,
all material filings, court papers and other related documents. Each party shall
consider the timely given, reasonable comments and advice of the other party
with respect to the strategy employed and submissions made relative to any
Trademark enforcement actions. The party enforcing such Trademark action shall
retain for its own account any damages or other monetary relief obtained in
connection therewith.

         2.4      OWNERSHIP OF PROPERTY RIGHTS.

                  Each party will retain ownership of all information, data,
Know-How, inventions, discoveries, programs, copyrights, improvements, devices,
designs, apparatus, patents, patent applications, practices, processes, methods,
products, techniques, trade secrets, ideas, or other intellectual property owned
by it at the commencement of this Agreement.

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3.       SUPPLY OF PRODUCTS

         3.1      MANUFACTURE AND SUPPLY OF PRODUCTS.

                  (a)      Subject to the provisions of this Section 3, during
the Term of this Agreement, NOVAVAX shall use Commercially Reasonable Efforts to
manufacture or have manufactured for and supply to KING, Products for KING's
promotion, marketing, distribution, and sale of the Products in the Territory.
All Products supplied under this Agreement are to be supplied in finished form,
in the quantities specified in KING's purchase orders placed with NOVAVAX
pursuant to Section 3.2 below and in conformity with the Specifications for the
Product.

                  (b)      NOVAVAX may subcontract all or any part of its
manufacturing obligations hereunder if it provides no less than six (6) months'
written notice of its intent to do so to KING, and KING (i) declines to take
over such manufacturing obligations and (ii) provides its consent to such
subcontractor, which consent shall not be unreasonably withheld or delayed. Any
such subcontractor shall be reputable and shall have sufficient expertise to
perform its obligations. Notwithstanding the foregoing, NOVAVAX shall not be
required to notify KING or obtain KING's consent with respect to its purchase of
materials from third parties for use in its manufacture of the Products
hereunder.

                  (c)      In the event that NOVAVAX is or reasonably expects to
be unable to supply KING with KING's requirements of Products, based on KING's
most recent Binding Quarterly Forecast, NOVAVAX shall so notify KING and KING
shall, in addition to KING's other remedies, be permitted to manufacture or have
manufactured that quantity of KING's requirements of Products which NOVAVAX is
obligated to but is unable to supply hereunder.

                  (d)      NOVAVAX shall manufacture, package, label, and ship
or cause to be manufactured, packaged, labeled and shipped the Products and
samples of the Products in conformity with the Specifications for the Product
and in accordance with all applicable laws, including, without limitation, the
Act and all applicable regulations thereunder, the NDA and current Good
Manufacturing Practices and all other applicable laws in the U.S. or in the
Territory.

         3.2      QUARTERLY FORECASTS; PURCHASE ORDERS.

                  (a)      KING shall provide NOVAVAX with a rolling fifteen
(15) month forecast of its expected purchases of the Product, at least one full
Calendar Quarter prior to the Calendar Quarter during which KING desires that
NOVAVAX supply it with the Products. The forecast for the first three (3) months
in each fifteen (15) month forecast shall be binding upon KING, and the forecast
for the subsequent twelve (12) months shall not be binding. The

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first such fifteen (15) month forecast shall be provided by KING to NOVAVAX at
least one full Calendar Quarter prior to the Calendar Quarter in which the first
commercial sale of the Product following regulatory approval to sell the Product
in the Territory for use in humans is projected ("First Commercial Sale").

                  (b)      Under Section 3.2(a) above, the forecast for those
quarters which is binding upon KING and NOVAVAX shall be a "Binding Quarterly
Forecast," and the forecasts under Section 3.2(a) which are non-binding upon
KING and NOVAVAX shall be "Non-binding Forecasts." A Binding Quarterly Forecast
shall be accompanied by an order for the Product reflected in the Binding
Quarterly Forecast, subject to quantity modifications as set forth in Section
3.2(c) below.

                  (c)      KING may modify the order represented by a Binding
Quarterly Forecast for a period of thirty (30) days after receipt of the Binding
Quarterly Forecast by NOVAVAX, within the constraints set forth below. The
quantity of each Product ordered by KING in any Calendar Quarter shall not be
less than seventy-five percent (75%) of the quantity of such Product specified
in the Binding Quarterly Forecast applicable to such Calendar Quarter.
Additionally, NOVAVAX shall not be obligated to supply that quantity of any
Product in any Calendar Quarter that is more than one hundred twenty-five
percent (125%) of the quantity of such Product specified in the Binding
Quarterly Forecast applicable to such Calendar Quarter, but will use its
Commercially Reasonable Efforts to supply KING's orders of up to one hundred
fifty percent (150%) of the quantity of such Product specified in the Binding
Quarterly Forecast applicable to such Calendar Quarter.

                  (d)      KING shall place purchase orders with NOVAVAX in
accordance with the applicable Binding Quarterly Forecast. The orders placed by
KING hereunder shall specify, in a format agreed upon by the parties, the
quantities of each Product desired (consistent with Section 3.2(c) above), the
place(s) to which delivery is to be made, and the manner and dates by which
delivery is to be made (said delivery dates to be no earlier than ninety (90)
calendar days after the purchase order date). All purchase orders shall be sent
by KING to the attention of the following employee of NOVAVAX or as otherwise
instructed by NOVAVAX.

                  Name:        James Mirto
                  Title:       Senior Vice President, Chief Operating Officer
                  Address:     Novavax, Inc.
                               8320 Guilford Road
                               Columbia, Maryland  21046
                  FAX:         (301) 854-3901

The terms of any purchase order or acknowledgment thereof or any other documents
relating to KING's purchase of Products from NOVAVAX hereunder

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shall be superceded by the terms of this Agreement. All such purchase orders
shall be deemed accepted unless NOVAVAX notifies KING of its non-acceptance no
later than seven (7) days after its receipt of such purchase order.

         3.3      DELIVERY OF PRODUCTS.

                  (a)      Subject to the terms and conditions of this
Agreement, including Section 3.2(e), NOVAVAX shall execute all accepted purchase
orders consistent with this Agreement by delivery to the destination within the
United States recited therein of all ordered quantities of the Products no later
than the delivery dates provided in KING's purchase orders. Subject to Section
3.2(e), KING may reschedule shipment of any Product order, for not greater than
120 days, upon written notice to NOVAVAX at least sixty (60) days prior to the
scheduled shipping date for such order. Title and risk of loss for each order
will pass to KING when such order of Products is delivered to its destination in
the United States.

                  (b)      As of the time of such delivery by NOVAVAX, each lot
of the Products will conform to its Specifications. NOVAVAX shall perform
release testing in a manner consistent with testing methods agreed upon by the
parties or, absent any such agreement, as heretofore conducted by NOVAVAX.
NOVAVAX shall provide to KING a certificate of analysis with each shipment of
the Products to KING or its designated recipient stating that the Products
conform to their Specifications and meet the release specifications. The
certificate of analysis shall be in a format agreed upon by the parties. Upon
KING's written request, NOVAVAX will also provide KING with a copy of the
relevant available manufacturing and controls information for the applicable
lot(s) ordered.

                  (c)      All purchase orders for the Products placed by KING
shall be whole number multiples of the production batch sizes used by NOVAVAX.
The parties acknowledge and agree that the quantity of the Product delivered to
KING hereunder may differ by up to ten percent (10%) from the quantity requested
in the purchase order. In the event that the quantity delivered hereunder
differs from the quantity requested in the purchase order, KING shall pay
NOVAVAX for the quantity delivered rather than the quantity requested in the
purchase order.

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         3.4      PRODUCT SAMPLES.

                  Except as provided in this Section 3.4, Product samples shall
be deemed Products hereunder and shall be subject to the same terms and
conditions of other Products. NOVAVAX shall provide KING with samples of the
Products to be used by KING solely in marketing and promoting the Products in
the Territory. NOVAVAX shall ship the samples to one central warehouse of KING
in the United States, as designated by KING, and title and risk of loss and
responsibility for handling and warehousing of the samples shall pass to KING
upon delivery to such warehouse in the United States. All samples of the
Products provided to KING hereunder shall be accompanied by an appropriate
certificate of analysis of the Product Specifications and an indication of
expiration dating.

         3.5      LABELING AND PACKAGING COSTS.

                  KING shall reimburse NOVAVAX for the direct costs of any
manufacturing, packaging, and labeling materials and components paid for by
NOVAVAX in reliance upon forecasts submitted by KING hereunder which become
obsolete and which cannot be returned for a refund or otherwise used by NOVAVAX
upon any change by KING or its Affiliate in the packaging or labeling of the
Products. At its option, KING will pay for the return or destruction of the
obsolete materials or components.

4.       CERTAIN REGULATORY MATTERS

         4.1      LICENSES.

                  Except as otherwise set forth in this Agreement, each party
hereto shall, at its sole cost and expense, maintain in full force and effect
all necessary licenses, permits and other authorizations required by law,
regulation, ordinance or statute to carry out its duties and obligations in the
Territory under this Agreement.

         4.2      REGULATORY RESPONSIBILITY.

                  All regulatory matters regarding the Products within and
arising from or related to the promotion, marketing or sales of the Products
within the Territory shall be the responsibility of, and shall remain under the
control of KING, subject to NOVAVAX's responsibilities in matters related to the
Products outside the Territory, including without limitation NOVAVAX's
responsibilities relating to the manufacturing of the Products in accordance
with applicable FDA regulations and current Good Manufacturing Practices.
Notwithstanding the foregoing, KING shall promptly provide NOVAVAX with copies
of all communications received from any regulatory agency or authority
concerning the Products or any Marketing Materials related to the Products in
the Territory

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and/or arising from or related to the promotion, marketing or sales of the
Products within the Territory and shall submit copies of all such communications
and filings to be made to any regulatory agency or authority within the
Territory for prior review and comment within five (5) business days. KING shall
provide adequate notice to NOVAVAX and shall include NOVAVAX in all meetings
with a regulatory agency or authority within the Territory, electronic, in
person, or otherwise. KING shall give due consideration to all comments timely
made by NOVAVAX and shall notify NOVAVAX, in writing, if it declines to address
any such comments, stating the reason therefor.

         4.3      EFFICACY AND SAFETY INFORMATION.

                  Each party shall furnish the other with efficacy and safety
information in its possession as reasonably requested to assist each party in
the performance of its obligations under this Agreement, including without
limitation relevant clinical and safety data included in the NDA (or comparable
filing in the Territory) for the Products and additional information, if any,
related to the efficacy and safety profile of the Products. Except for that
information that is to be disclosed to OB/GYN's in connection with conducting
details, such information shall be treated as Confidential and Proprietary
Information pursuant to Section 8 of this Agreement and shall not be disclosed
to third parties without the prior written approval or direction of the party
owning such Confidential and Proprietary Information.

         4.4      NOTICE OF ADVERSE EVENTS.

                  Each party shall promptly notify the other party of any
event(s) that materially affect(s) or could reasonably be expected to materially
affect the marketing of the Products, including without limitation adverse drug
reactions and governmental inquiries. Serious Adverse Events for the Products
learned of by KING shall be submitted in writing to NOVAVAX within two (2)
business days from the date of learning thereof by KING. Non-Serious Adverse
Events for the Products learned of by KING shall be submitted in writing to
NOVAVAX no more than five (5) business days from the date of learning thereof by
KING. KING and/or its Affiliates shall have the sole responsibility for
reporting and responding to such events to applicable regulatory authorities in
the Territory; provided, that NOVAVAX may take such actions (including issuing
such reports) as it determines are required by applicable law. KING shall
promptly provide NOVAVAX with copies of all periodic reports and product safety
update reports relating to the Products which are filed or received from third
parties relating to the Territory. Notwithstanding the foregoing, within one
hundred twenty (120) days after the Effective Date, the parties shall meet and
establish a standard operating procedure ("SOP") addressing the responsibilities
of each party with respect to adverse event reporting, which SOP shall supercede
this Section 4.4, it being understood, however, that KING shall have the

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responsibility of reporting all adverse events to the appropriate regulatory
authorities in the Territory.

                  4.5      RECALLS; PRODUCT TECHNICAL COMPLAINTS.

                  (a)      KING shall have the sole authority and responsibility
to respond to any regulatory agencies in the Territory, to respond to Product
Technical Complaints and medical complaints and to handle all recalls or market
withdrawals of the Products in accordance with applicable law, at its cost and
expense; provided, however, that if any such recalls or market withdrawals of
the Products are caused solely by actions or inactions by NOVAVAX constituting a
breach of the provisions of this Agreement or a violation of applicable law,
NOVAVAX, as KING's sole remedy, shall bear all reasonable costs associated with
such actions or inactions in connection therewith, provided, however, that
NOVAVAX shall have no obligation to reimburse KING for any incidental or
consequential damages incurred in connection therewith, including, without
limitation, any lost profits.

                  (b)      Each party shall promptly (but in any case, not later
than 48 hours) notify the other party in writing of any order, request or
directive of a court or other governmental authority to recall or withdraw a
Product. KING shall be solely responsible for determining whether to issue a
recall or withdrawal (but shall comply with all applicable laws, regulations and
governmental guidelines in making such determination) and for the cost and
expense of any such recall or withdrawal of the Products, provided, however,
that KING shall give due consideration to all comments timely made by NOVAVAX
relating to the manufacturing of the Products and shall notify NOVAVAX, in
writing, if it declines to address any such comments, stating the reason
therefor. If a recall or market withdrawal is due to KING's failure to satisfy
its obligations hereunder, then NOVAVAX shall be relieved of its obligations to
supply the Product hereunder until the cause of such recall or withdrawal has
been resolved to the satisfaction of the parties and the FDA.

                  (c)      In the event of any recall or product withdrawal
resulting solely from NOVAVAX's wrongful or willfully negligent acts or
omissions, NOVAVAX shall, as KING's sole remedy (together with the recovery set
forth in Sections 4.5(a) and (d)), for such act or omission, at the election of
KING, either:

                           (i)      supply Products, without charge to KING, in
an amount sufficient to replace the amount of Products recalled or withdrawn; or

                           (ii)     refund to KING, or give credit to KING
against outstanding receivables due from KING against the Purchase Price or
Royalty Payments for Products to be delivered to KING in the future, in amounts
equal to the price paid by KING to NOVAVAX for Products so recalled or withdrawn
plus

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the reasonable transportation costs incurred by KING and not recovered by KING
in respect of such recalled or withdrawn Products.

                  (d)      In the event of any recall or withdrawal arising out
of or resulting from one party's breach of this Agreement, negligence or willful
misconduct , the breaching party shall also pay to the other party, the other
party's reasonable out-of-pocket expenses incurred in connection with such
recall or withdrawal.

         4.6      NOTICE OF GOVERNMENT INSPECTIONS.

                  Each party agrees that, to the extent it becomes aware of the
results, observations and/or outcome of any inspections or audits of the
facilities or operations involved in the manufacture, processing, testing or
packaging of the Products conducted by governmental agencies, including without
limitation the FDA, it will notify the other of any such information as it
relates to the Products within three (3) days of obtaining the information. Each
party will provide the other with copies of reports of quality audits conducted
by it and will apprise the other of material manufacturing, marketing,
promotion, sales or other issues affecting supply of the Products.

         4.7      GOVERNMENT INQUIRIES.

                  Upon being contacted by any federal, state, or local agency
for any regulatory purpose pertaining specifically to this Agreement or to the
Products, a party shall immediately notify the other party. Either party may
permit unannounced inspections of Products or facilities by a regulatory agency
with competent jurisdiction and respond to the extent necessary to comply with
its obligations under applicable law.

         4.8      MEDICAL INQUIRIES.

                  KING shall handle all medical inquiries concerning the
Products in or from the Territory. KING shall notify NOVAVAX of any medical
information requests and/or medical inquiries.

5.       FEES AND EXPENSES

         5.1      PURCHASE PRICE.

                  (a)      KING shall purchase from NOVAVAX, and NOVAVAX shall
sell to KING, the Products at the price equal to the Cost of Products plus ten
percent (10%) (the "Purchase Price"). NOVAVAX may, from time to time, by written
notice to KING, increase the purchase price for one or more Products by an
amount equal to the increase in NOVAVAX's costs for labor and materials used in

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connection with the manufacture, storage and/or delivery to KING of such
Products; provided, however, that during the twelve (12) month period following
the Effective Date, NOVAVAX shall not increase the purchase price for any
Product because of any increased labor cost experienced by NOVAVAX.

                  (b)      In addition to the Purchase Price, KING shall pay all
actual freight, insurance and government sales, use, excise, property, import,
export or similar taxes or excises imposed on purchases for resale, and duties
and other fees (except tax on income to NOVAVAX) incurred in connection with the
sale and shipment of the Products to KING.

                  (c)       NOVAVAX shall keep adequate and complete records, in
accordance with GAAP, of all Costs of Products. Such records shall include all
information necessary to verify the total amount and computation of the Purchase
Price due hereunder and NOVAVAX's compliance with the terms and conditions of
this Agreement, and shall be available once per year to inspection by or on
behalf of KING during normal business hours, upon reasonable notice, to verify
such costs and whether an increase in such costs has occurred and to verify
NOVAVAX's compliance with this Agreement. NOVAVAX shall retain such records for
not fewer than twenty-four (24) months after the close of any calendar year to
which they relate or such period as required by the FDA. NOVAVAX agrees to make
prompt adjustment, if necessary, to compensate for any errors or omissions
disclosed by such inspection. Should such inspection reveal a shortfall of more
than three percent (3%) between the costs actually incurred and the Costs of
Products reported to KING, the cost of such inspection shall be paid by NOVAVAX.

                  (d)      Payments to NOVAVAX for the Purchase Price of
delivered Products shall be made by KING within thirty (30) days after the later
of (i) the date of delivery thereof to the destination specified by KING, and
(ii) the date of invoice from NOVAVAX.

         5.2      ROYALTY PAYMENT.

                  (a)      In addition to the amounts paid under Section 5.1,
KING agrees to pay royalties only on the Net Sales of the Products at an annual
rate of seven and one-half percent (7.5%) of Net Sales of the Products in the
Territory. Such royalties are payable forty-five (45) days after the end of each
Calendar Quarter in which Products are sold during the Term of this Agreement.

                  (b)      KING shall keep adequate and complete records, in
accordance with GAAP, showing all Net Sales of Products with respect to which
royalties are due under this Agreement. Such records shall include all
information necessary to verify the total amount and computation of royalties
due hereunder and KING's compliance with the terms and conditions of this
Agreement, and shall be available once per year to inspection by or on behalf of

                                       11
<PAGE>   15

NOVAVAX during normal business hours, upon reasonable notice, to verify the
amounts thereof or to ascertain such amounts in the event of a failure of KING
to report and to verify KING's compliance with this Agreement. KING shall retain
such records for not fewer than twenty-four (24) months after the close of any
calendar year to which they relate or such period as required by the FDA. KING
agrees to make prompt adjustment, if necessary, to compensate for any errors or
omissions disclosed by such inspection. Should such inspection reveal a
shortfall of more than three percent (3%) between the royalties reported and
those actually owed by KING, the cost of such inspection shall be paid by KING.

         5.3      DISTRIBUTION, WAREHOUSING, BILLING, PRICING.

                  KING (and/or its Affiliates) shall have the sole
responsibility for the distribution, warehousing, billing and order confirmation
of the Products after receipt at the designated destination and for the
collection of receivables resulting from sales of the Products in the Territory.
KING shall have the sole authority to determine the price of the Products in the
Territory during the Term, including resale price increases and decreases and
the timing thereof.

6.       INSPECTION AND WARRANTY OF PRODUCTS

         6.1      INSPECTION BY KING.

                  Within forty-five (45) days from the date of delivery of
Products to the destination specified by KING, KING may analyze such Products
delivered to KING for purposes of determining whether the same meet their
Specifications and were manufactured in accordance with the NDA ("Acceptable
Products"). KING shall notify NOVAVAX in writing within said forty-five (45)
days of any Product or portion thereof which KING is returning because it is not
an Acceptable Product.

         6.2      DISPUTES OVER PRODUCTS.

                  If NOVAVAX, after good faith consultation with KING, disputes
any finding by KING that a Product is not an Acceptable Product, then
representative samples of such Product shall be forwarded to a third party
jointly selected by NOVAVAX and KING, in their reasonable discretion, for
analysis, which analysis shall be performed in compliance with applicable FDA
regulations and governmental regulations in the Territory for re-testing of
pharmaceutical products. The findings of such third party regarding whether the
Product was an Acceptable Product shall be binding upon the parties. The cost of
such analysis by such third party shall be borne by the party whose findings
differed from those generated by such third party.

                                       12
<PAGE>   16

         6.3      REPLACEMENT OF PRODUCTS THAT ARE NOT ACCEPTABLE PRODUCTS.

                  NOVAVAX shall, as KING's option, either replace any Product
order, or portion thereof, which is not an Acceptable Product, at its cost and
expense, including shipping costs, or refund to KING the payments made for such
returned Products. NOVAVAX shall instruct KING as to the disposition of any
Product order or portion thereof determined not to be an Acceptable Product. At
the sole option of NOVAVAX, said Product may be returned to NOVAVAX, at
NOVAVAX's expense including shipping costs, or destroyed in an environmentally
acceptable manner, in accordance with applicable governmental regulations, at
NOVAVAX's expense.

7.       TERM AND TERMINATION

         7.1      TERM OF AGREEMENT.

                  (a)      The initial Term of this Agreement (the "Initial
Term") shall commence as of the Effective Date hereof and, unless terminated
sooner or extended as provided below, shall continue until the last to expire of
any patent rights covering the Products which grant exclusivity to the
marketing, distribution and sale of the Products (the Initial Term, as extended
or sooner terminated, the "Term").

                  (b)      If NOVAVAX (or any of its Affiliates) shall obtain
any additional patent or other exclusive rights with respect to the
manufacturing, sale, marketing or promotion of the Products, and such rights
shall have a term which extends beyond the Initial Term ("Additional Exclusivity
Rights"), then NOVAVAX shall so notify KING promptly and KING may, in its sole
discretion, elect to extend the Initial Term until the expiration or termination
of such Additional Exclusivity Rights (the "Extended Promotion Term"). If KING
shall elect to extend the Initial Term pursuant to this Section 7.1(b), then
KING shall provide written notice thereof to NOVAVAX at least sixty (60) days
prior to the expiration of the Initial Term, in which case the terms and
conditions of this Agreement shall remain in full force and effect until the
expiration of the Extended Promotion Term, unless terminated sooner as provided
herein.

         7.2      TERMINATION BY NOVAVAX.

                  (a)      NOVAVAX shall have the right to terminate this
Agreement at any time upon written notice to KING, if KING breaches in a
material way any of the representations, warranties, covenants or agreements set
forth in this Agreement or otherwise materially defaults in the performance of
any of its duties or obligations under this Agreement, which breach or default
shall not be cured within sixty (60) days after written notice is given to KING
specifying the breach or default.

                                       13
<PAGE>   17

                  (b)      To the extent permitted by law, NOVAVAX shall have
the right to terminate this Agreement immediately upon notice to KING, if KING
is declared bankrupt or insolvent where there is an assignment for the benefit
of creditors, or if a receiver is appointed or proceedings commenced (and not
dismissed within ninety (90) days), voluntarily or involuntarily, under any
bankruptcy or similar law.

         7.3      TERMINATION BY KING.

                  KING shall have the right to terminate this Agreement, in its
sole discretion, as follows:

                  (a)      at any time on or before June 30, 2001 or immediately
upon notice, in the event that KING, in conducting its continued due diligence
on the Products, determines, in its sole discretion, that there are safety or
efficacy concerns relating to the Products;

                  (b)      immediately upon written notice to NOVAVAX, if (i)
the FDA shall not have given written notice to NOVAVAX that the FDA has accepted
the NDA for the ESTRASORB(R) Model Claims on or prior to March 31, 2002, or (ii)
KING is advised between March 31, 2002 and December 31, 2002, by a nationally
recognized pharmaceuticals consulting firm, that the FDA is not expected to
approve the NDA for the ESTRASORB(R) by December 31, 2002 or (iii) the Product
is not approved for marketing and sale for use in humans by the applicable
governmental authorities in the Territory by December 31, 2004;

                  (c)      at any time upon written notice to NOVAVAX, if
NOVAVAX breaches in a material way any of the representations, warranties,
covenants or agreements set forth in this Agreement or otherwise materially
defaults in the performance of any of its duties or obligations under this
Agreement, which breach or default shall not be cured within sixty (60) days
after written notice is given to NOVAVAX specifying the breach or default;

                  (d)      KING shall have the right to terminate this Agreement
with respect to a specific country within the Territory upon thirty (30) days'
prior notice to NOVAVAX if there has been a material adverse change in the
market for any Product in such country such as a recall or withdrawal of a
Product, or a safety problem related to a Product;

                  (e)      immediately upon notice to NOVAVAX, to the extent
permitted by law, if NOVAVAX is declared bankrupt or insolvent where there is an
assignment for the benefit of creditors, or if a receiver is appointed or
proceedings commenced (and not dismissed within ninety (90) days), voluntarily
or involuntarily, under any bankruptcy or similar law; and

                                       14
<PAGE>   18

                  (f)      an "Event of Default" shall have occurred under that
certain 4% Convertible Senior Note, dated December 19, 2000, made by NOVAVAX to
KING.

         7.4      EFFECTS OF TERMINATION.

                  (a)      Upon termination of this Agreement, KING shall pay
NOVAVAX for all direct costs associated with raw materials or components used in
manufacturing, packaging, or labeling the Products, to the extent that such
materials or components were purchased in reasonable quantities based on
forecasts submitted by KING hereunder, which NOVAVAX determines, in its
reasonable discretion, that it cannot practicably reuse in the manufacturing,
packaging, or labeling of other products. At its option, KING will pay for the
return or destruction of the obsolete materials or components.

                  (b)      Neither the termination nor expiration of this
Agreement shall release or operate to discharge either party from any liability
or obligation that may have accrued prior to such termination or expiration. Any
termination of this Agreement as provided herein shall not be an exclusive
remedy but shall be in addition to any remedies whatsoever that may be available
to the terminating party.

                  (c)      Notwithstanding the giving of any notice of
termination pursuant to this Section 7, each party shall continue to fulfill its
obligations under this Agreement at all times until the effective date of any
such termination.

         7.5      ACTIONS UPON TERMINATION.

                  (a)      Except as set forth in Section 7.5(b) below, upon the
termination or expiration of this Agreement for any reason, KING shall
immediately cease all of its promotional and marketing activities for the
terminated Products, discontinue any use of the NOVAVAX Trademarks related to
the terminated Products, and, at NOVAVAX's election, return to NOVAVAX or
destroy all sales training and Marketing Materials for the terminated Products
containing NOVAVAX Trademarks and any remaining terminated Product samples (not
already distributed or destroyed with destruction certified by KING).

                  (b)      Notwithstanding Section 7.5(a), KING may continue to
market, promote, distribute and sell the Product using the NOVAVAX Trademarks in
accordance with the terms of this Agreement until the earlier of such time as
KING's inventory of the Product existing at the time of termination is depleted
or the dating on such Product has expired.

                                       15
<PAGE>   19

         7.6      SURVIVAL.

                  The representations, warranties, covenants and agreements of
the parties in Sections 7, 8, 9, 10, 11 and 12 hereof shall survive any
expiration or termination of this Agreement.

         7.7      PAYMENTS UPON TERMINATION.

                  (a)      The expiration or termination of this Agreement
pursuant to this Section 7 with respect to any Product shall not release (i)
either party from any obligation to pay to the other party any amounts accrued
under Section 5 of this Agreement in connection with activities completed,
expenses accrued and Net Sales realized for such Product with respect to the
period prior to the effective date of such expiration or termination; provided,
that no further amounts shall be payable under Section 5, except as provided for
in this Section 7.

8.       CONFIDENTIAL INFORMATION

         8.1      DUTY OF CONFIDENTIALITY.

                  Each party acknowledges that it may receive confidential or
proprietary information of the other party in the performance of this Agreement,
including without limitation information obtained or reviewed in connection with
any audits or investigations performed pursuant to Section 5.1(c) or Section
5.2(b) of this Agreement. Each party shall hold confidential and shall not,
directly or indirectly, disclose, publish or use for the benefit of any third
party or itself, except in carrying out its duties hereunder, any Confidential
or Proprietary Information of the other party or Confidential or Proprietary
Information jointly developed by the parties, without first having obtained the
furnishing party's written consent to such disclosure or use. "Confidential or
Proprietary Information" shall include without limitation Know-How, scientific
information, clinical data, efficacy and safety data, adverse event information,
formulas, methods and processes, Specifications, pricing information (including
discounts, rebates and other price adjustments) and other terms and conditions
of sales, customer information, business plans, and all other intellectual
property. This restriction shall not apply to any information within the
following categories:

                           (i)      is or becomes part of the public domain
         other than by unauthorized acts of the party obligated not to disclose
         such information or its Affiliates, sublicensees, consultants and
         contractors, as applicable;

                           (ii)     can be shown by written documentation to
         have been disclosed to or already in the possession of the receiving
         party or its Affiliates or sublicensees by a third party, provided such
         information was

                                       16
<PAGE>   20

         not obtained by such third party directly or indirectly from the other
         party under this Agreement;

                           (iii)    can be shown by written documentation to
         have been independently developed by the receiving party or its
         Affiliates without breach of any of the provisions of this Agreement by
         personnel without access to the Confidential Information;

                           (iv)     is disclosed by the receiving party pursuant
         to interrogatories, formal requests for information or documents,
         subpoena, or a civil investigative demand of a court or governmental
         agency; provided, however, that, to the extent practicable, the
         receiving party shall notify the other party promptly following receipt
         thereof so that the other may seek a protective order or other
         appropriate remedy to prevent or limit such disclosure, and provided
         further that the disclosing party furnishes only that portion of the
         information which it is advised by counsel is legally required and
         imposes such obligations of secrecy as are possible in that regard;

                           (v)      is required to be disclosed by a party under
         any statutory, regulatory or similar legislative requirement or any
         rule of any stock exchange to which it or any Affiliate is subject;
         provided, however, that the non-disclosing party shall be allowed to
         review the proposed disclosure and the disclosing party agrees to
         consider in good faith any proposed revisions thereof provided to the
         disclosing party within two (2) business days of the non-disclosing
         party's receipt of the proposed disclosure and the parties shall seek
         confidential treatment for such disclosure as permitted by applicable
         law; or

                           (vi)     is required by authorities to obtain
regulatory approval to market, promote, or sell the Products in the Territory.

         8.2      SURVIVAL.

         The obligations set forth in this Section 8 shall survive the
termination or expiration of this Agreement for a period of five (5) years. The
confidentiality obligations described in this Section 8 shall be in addition to
the parties' obligations under the Confidentiality Agreement dated as of
September 1, 2000 (the "Confidentiality Agreement"), except that to the extent
there is a conflict between the Confidentiality Agreement and provisions of this
Agreement, this Agreement shall govern.

                                       17
<PAGE>   21

9.       INDEMNIFICATION AND INSURANCE

         9.1      INDEMNIFICATION BY KING.

                  KING shall defend, indemnify and hold NOVAVAX and its
Affiliates, and their respective officers, directors, employees, successors and
assigns, harmless from and against any and all claims, liabilities, losses,
costs, actions, suits, damages and expenses (other than special, incidental,
consequential or punitive damages, but including attorneys' fees and costs)
arising out of: (a) any breach by KING of any representation, warranty or
covenant contained in this Agreement; and (b) any claims by third parties
relating to the performance or nonperformance of KING's obligations under this
Agreement; provided, however, that KING shall not be required to indemnify
NOVAVAX with respect to any such claim, liability, loss, cost, action, suit,
damage or expense hereunder to the extent the same is otherwise covered by
NOVAVAX's indemnification obligation in Section 9.2, or which arises from
NOVAVAX's negligent act or omission or intentional misconduct or that of any
NOVAVAX Affiliate.

         9.2      INDEMNIFICATION BY NOVAVAX.

                  NOVAVAX shall defend, indemnify and hold KING and its
Affiliates, and their respective officers, directors, employees, successors and
assigns, harmless from and against any and all claims, liabilities, losses,
costs, actions, suits, damages and expenses (other than special, incidental,
consequential or punitive damages, but including attorneys' fees and costs)
arising out of: (a) any breach by NOVAVAX of any representation, warranty or
covenant contained in this Agreement; (b) the infringement or alleged
infringement of any patent, trademark or other intellectual property rights of a
third party by its activities with respect to the Products or Trademarks in
accordance with the terms and conditions of this Agreement; (c) any personal
injury (including death) and/or property damage resulting from the handling,
possession or use of the Products in accordance with NOVAVAX's written
instructions therefor that have been provided to KING; (d) any claims by third
parties relating to the performance or nonperformance of NOVAVAX's obligations
under this Agreement; and (e) any other liability arising out of the
manufacture, marketing, labeling, distribution or use of the Products in
accordance with NOVAVAX's written instructions therefor that have been provided
to KING; provided, however, that NOVAVAX shall not be required to indemnify KING
with respect to any such claim, liability, loss, cost, action, suit, damage or
expense hereunder to the extent covered by KING's indemnification obligation in
Section 9.1, or which arises from KING's negligent act or omission or
intentional misconduct or that of any KING Affiliate or which arises from any
modification of the Products.

         9.3      CLAIMS PROCEDURES.

                  A party (the "Indemnitee") which intends to claim
indemnification

                                       18
<PAGE>   22

under this Section 9 shall notify the other party (the "Indemnitor") within a
reasonable time in writing of any action, claim or liability in respect of which
the Indemnitee believes it is entitled to claim indemnification, provided that
the failure to give timely notice to the Indemnitor shall not release the
Indemnitor from any liability to the Indemnitee to the extent the Indemnitor
(including its right to defend) is not prejudiced thereby. The Indemnitor shall
have the right, by notice to the Indemnitee, to assume the defense of any such
action or claim within the fifteen (15) day period after the Indemnitor's
receipt of notice of any action or claim with counsel of the Indemnitor's choice
and at the sole cost of the Indemnitor. If the Indemnitor does not so assume the
defense of such third party claim, then the Indemnitee may assume such defense
with reasonable counsel of its choice and at the sole cost of the Indemnitor. If
the Indemnitor so assumes such defense, then the Indemnitee may participate
therein through counsel of its choice, but at the sole cost of the Indemnitee.
The party not assuming the defense of any such claim shall render all reasonable
assistance as is requested to the party assuming such defense, and all
reasonable out-of-pocket costs of such assistance shall be for the account of
the Indemnitor. No such claim shall be settled other than by the party defending
the same, and then only with the consent of the other party which shall not be
unreasonably withheld; provided that the Indemnitee shall have no obligation to
consent to any settlement of any such action or claim which imposes on the
Indemnitee any liability or obligation which cannot be assumed and performed in
full by the Indemnitor, and the Indemnitee shall have no right to withhold its
consent to any settlement of any such action or claim if the settlement involves
only the payment of money by the Indemnitor or its insurer.

         9.4      INSURANCE.

                  Each party shall maintain insurance (either through purchase
of a policy from a nationally recognized third party insurer or through
maintenance of a self-insurance program) against such risks and upon such terms
(including coverages, deductible limits and self-insured retentions) as is
customary for the activities to be conducted by such party under this Agreement
and is appropriate to cover its indemnification obligations hereunder. Each
party shall name the other as an additional insured on such party's relevant
insurance policies, as its interests may appear, and shall furnish to the other
party evidence of such insurance, upon request.

                                       19
<PAGE>   23

10.      REPRESENTATIONS AND WARRANTIES

         10.1     BY KING.

                  KING represents and warrants to NOVAVAX that:

                  (a)      the execution, delivery and performance of this
Agreement by KING does not conflict with, or constitute a breach of or under,
any order, judgment, agreement or instrument to which KING is a party; and

                  (b)      the execution, delivery and performance of this
Agreement by KING does not require the consent of any Person or the
authorization of (by notice or otherwise) any governmental or regulatory
authority, except as otherwise expressly provided in this Agreement.

         10.2     BY NOVAVAX.

                  NOVAVAX represents and warrants to KING that:

                  (a)      the execution, delivery and performance of this
Agreement by NOVAVAX does not conflict with, or constitute a breach of or under,
any order, judgment, agreement or instrument to which NOVAVAX is a party;

                  (b)      the execution, delivery and performance of this
Agreement by NOVAVAX does not require the consent of any Person or the
authorization of (by notice or otherwise) any governmental or regulatory
authority, except as expressly provided in this Agreement;

                  (c)      the rights granted by NOVAVAX to KING hereunder do
not conflict with any rights granted by NOVAVAX to any third party;

                  (d)      subject to KING's responsibilities as set forth in
this Agreement, NOVAVAX has sufficient rights in and to the Products and all
intellectual property, use, development, manufacturing, marketing, distribution
and sale rights related thereto necessary or advisable for such purposes as
contemplated by this agreement (the "Product Rights"), free and clear of any
liens or encumbrances;

                  (e)      there are no agreements between NOVAVAX and any
Person with respect to the rights of NOVAVAX in the Territory in the Products
and the Product Rights;

                  (f)      NOVAVAX has the right to and, as of the Effective
Date, has no reason to believe it will not have a continuous and sufficient
supply of the active ingredient included in the Products during the entire Term;

                                       20
<PAGE>   24

                  (g)      it has no notice that any Product Rights, or that the
use thereof as contemplated under this Agreement, interfere or infringe on any
intellectual property rights owned or possessed by any Person;

                  (h)      there are no third party pending patent applications
which, if issued, may cover the use, development, manufacture, distribution or
sale of the Products;

                  (i)      there are no claims, judgments or settlements against
or owed by NOVAVAX or pending or threatened claims or litigation relating to the
Products or the Product Rights;

                  (j)      it has reviewed the available safety data relating to
the Products and has no reason to believe the Products are not safe;

                  (k)      as of the time the Products are delivered to KING's
designated destination hereunder and subject to KING's compliance with its
obligations hereunder, all such Products supplied hereunder conform to the
Specifications, will be manufactured in accordance with the NDA, and will not be
adulterated or misbranded.

                  (l)      it has not and will not use in any capacity the
services of any persons debarred under 21 U.S.C. Section 335(a) or 355(b) in
connection with the manufacture of the Products; and

                  (m)      any Product samples provided to KING hereunder have
been at all times in the control of NOVAVAX or its designate and meet applicable
Specifications contained in the NDA for the Product.

11.      NOTICES

         Except as otherwise specifically provided herein, any notice or other
documents to be given under this Agreement shall be in writing and shall be
deemed to have been duly given if sent by registered post, nationally recognized
overnight courier or confirmed facsimile transmission to a party (followed by
hard copy by mail) or delivered in person to a party at the address or facsimile
number set out below for such party or such other address as the party may from
time to time designate by written notice to the other:

         If to KING:

                  KING Pharmaceuticals, Inc.
                  501 Fifth Street
                  Bristol, Tennessee  37620
                  Attn:  President
                  Facsimile:  (423) 989-8055

                                       21
<PAGE>   25

                  with a copy (which shall not constitute notice) to:

                  KING Pharmaceuticals, Inc.
                  501 Fifth Street
                  Bristol, Tennessee  37620
                  Attn:  Executive Vice President and General Counsel
                  Facsimile:  (423) 989-6282

         If to NOVAVAX:

                  Novavax, Inc.
                  8320 Guilford Road
                  Columbia, Maryland  21046
                  Attn:  Chief Executive Officer
                  Telecopy:    (301) 854-3902

                  with a copy (which shall not constitute notice) to:

                  White & McDermott, P.C.
                  65 William Street, Suite 250
                  Wellesley, Massachusetts 02481
                  Attn:    David A. White
                  Telecopy:    (781) 237-8120

Any such notice or other document shall be deemed to have been received by the
addressee three (3) business days following the date of dispatch of the notice
or other document by post or, where the notice or other document is sent by
overnight courier, by hand or is given by facsimile, simultaneously with the
transmission or delivery thereof.

12.      MISCELLANEOUS PROVISIONS

         12.1     ASSIGNMENT; CHANGE OF CONTROL.

                  (a)      Neither party shall assign or otherwise transfer this
Agreement or any interest herein or right hereunder without the prior written
consent of the other party, and any such purported assignment, transfer or
attempt to assign or transfer any interest herein or right hereunder shall be
void and of no effect, except that without the prior written consent of NOVAVAX,
KING may assign its rights and obligations hereunder to an Affiliate. In the
case of an assignment in accordance with this Section 12.1, the assigning party
shall remain responsible for all of its obligations and agreements set forth
herein, notwithstanding such assignment and such transferee or successor shall
assume in writing the obligations of the party to which it is the transferee or
successor. Subject to the foregoing, this Agreement

                                       22
<PAGE>   26

shall be binding upon and inure to the benefit of the parties hereto and their
respective permitted successors and assigns.

                  (b)      NOVAVAX and KING acknowledge and agree that KING's
obligations, commitments (financial and otherwise) and investments pursuant to
the terms hereof and pursuant to various other commercial arrangements between
KING and NOVAVAX are based on the premise that (i) KING expects that it shall
take several years for the NOVAVAX Products to develop and mature to be viable
and economically profitable pharmaceutical products, and (ii) KING believes that
the best organizational and corporate structure to achieve these objectives is
for NOVAVAX to remain an independent biopharmaceutical company focused on the
research, development and commercialization of proprietary healthcare products
for women.

                  (c)      Upon a Change of Control of NOVAVAX, King may elect,
in King's sole option, to require NOVAVAX to (i) assign and transfer to KING all
rights of ownership to any governmental or regulatory applications or approvals
in the Territory issued or pending (including any correspondence with respect
thereto) with respect to any NOVAVAX Products and any trademarks associated with
any NOVAVAX Products in the Territory, and (ii) license to KING on an exclusive
and perpetual basis solely in the Territory all intellectual property rights and
Know How with respect to the NOVAVAX Products as may be necessary to make, use,
promote and sell the NOVAVAX Products in the Territory; provided, however, if
KING elects to exercise its rights set forth above, KING will pay NOVAVAX a
royalty of seven and one-half percent (7.5%) of the Net Sales of the NOVAVAX
Products received by KING, and such royalty payment shall be subject to the
terms contained herein.

                  (d)      NOVAVAX acknowledges and agrees that the agreements
contained in this Section 12.1 are an integral part of the transactions
contemplated in this Agreement, and that, without these agreements, KING would
not enter into this Agreement and certain other commercial arrangements with
NOVAVAX.

         12.2     GOVERNING LAW.

                  This Agreement shall be governed by, and construed in
accordance with, the laws of the State of Delaware, without giving effect to any
choice of law or conflict of law rules or provisions (whether of the State of
Delaware or any other jurisdiction) that would cause the application of the laws
of any jurisdiction other than the State of Delaware.

                                       23
<PAGE>   27

         12.3     NON-WAIVER.

                  The failure of either party to enforce or to exercise, at any
time or for any period of time, any term of or any right arising pursuant to
this Agreement does not constitute, and shall not be construed as, a waiver of
such term or right, and shall in no way affect that party's right later to
enforce or exercise such term or right.

         12.4     ENTIRE AGREEMENT.

                  This Agreement and the Confidentiality Agreements contain all
of the terms agreed to by the parties regarding the subject matter of this
Agreement and supersede any prior agreements, understandings or arrangements
between them, whether oral or in writing. This Agreement may not be amended,
modified, altered or supplemented except by means of a written agreement or
other instrument executed by both of the parties hereto. No course of conduct or
dealing between the parties shall act as a modification or waiver of any
provisions of this Agreement.

         12.5     JURISDICTION; VENUE.

                  (a)      Each of NOVAVAX and KING hereby waives personal
service of any process upon it in connection with any suit, action or proceeding
arising out of or relating to this Agreement or the transactions contemplated
hereby, and hereby covenants and agrees that all such service of process may be
made in the manner set forth in Section 11 with the same effect as though served
on it personally.

                  (b)      NOVAVAX hereby covenants and agrees that any suit,
action or proceeding initiated by NOVAVAX against KING, its affiliates,
subsidiaries, successors and/or assigns arising out of or relating to this
Agreement or the transactions contemplated hereby shall be brought exclusively
in the federal courts located in and/or state courts of the State of Tennessee.
In the event of any such suit, action or proceeding initiated by NOVAVAX, each
of NOVAVAX and KING hereby submit to the exclusive jurisdiction and venue of the
federal courts located in and state courts of the State of Tennessee and hereby
waive any and all objections based on jurisdiction or venue that such party may
have under applicable law or the Federal Rules of Civil Procedure. Each of the
parties hereby irrevocably designates CT Corporation in the State of Tennessee
(the "Tennessee Process Agent") as its designee, appointee and agent to receive,
for and on its behalf, service of process in the State of Tennessee in any such
suit, action or proceedings with respect to this Agreement and the transactions
contemplated hereby. Service on the Tennessee Process Agent shall be deemed
complete upon delivery thereof to the Tennessee Process Agent, provided that, in
the case of any such service upon the Tennessee Process Agent, the party
effecting such service shall also deliver a copy thereof to the other parties in

                                       24
<PAGE>   28

accordance with the notice provision set forth in Section 11. Each such party
shall take all such action as may be necessary to continue the appointment of
the Tennessee Process Agent in full force and effect or to appoint another
agent, who shall thereafter be referred to herein as the "Tennessee Process
Agent," so that each such party shall at all times have an agent for service for
the foregoing purposes in the State of Tennessee.

                  (c)      KING hereby covenants and agrees that any suit,
action or proceeding initiated by KING against NOVAVAX, its affiliates,
subsidiaries, successors and/or assigns arising out of or relating to this
Agreement or the transactions contemplated hereby shall be brought exclusively
in the federal courts located in and/or state courts of the State of Maryland.
In the event of any such suit, action or proceeding initiated by KING, each of
NOVAVAX and KING hereby submit to the exclusive jurisdiction and venue of the
federal courts located in and state courts of the State of Maryland and hereby
waive any and all objections based on jurisdiction or venue that such party may
have under applicable law or the Federal Rules of Civil Procedure. Each of the
foregoing parties hereby irrevocably designates CT Corporation in the State of
Maryland (the "Maryland Process Agent"), as its designee, appointee and agent to
receive, for and on its behalf, service of process in the State of Maryland in
any such suit, action or proceedings with respect to this Agreement and the
transactions contemplated hereby. Service on the Maryland Process Agent shall be
deemed complete upon delivery thereof to the Maryland Process Agent, provided
that in the case of any such service upon the Maryland Process Agent, the party
effecting such service shall also deliver a copy thereof to the other parties in
accordance with the notice provision set forth in Section 11. Each such party
shall take all such action as may be necessary to continue the appointment of
the Maryland Process Agent in full force and effect or to appoint another agent,
who shall thereafter be referred to herein as the "Maryland Process Agent," so
that each such party shall at all times have an agent for service for the
foregoing purposes in the State of Maryland.

         12.6     SEVERABILITY.

                  In the event that any of the provisions or a portion of any
provision of this Agreement are held to be invalid, illegal or unenforceable by
a court of competent jurisdiction or a governmental authority, such provision or
portion of provision shall be construed and enforced as if it had been narrowly
drawn so as not to be invalid, illegal or unenforceable and the validity,
legality and enforceability of the enforceable portion of any such provision and
the remaining provisions shall not be adversely affected thereby.

         12.7     RELATIONSHIP OF THE PARTIES.

                  The parties hereto are acting and performing as independent
contractors. Nothing in this Agreement creates the relationship of partnership,

                                       25
<PAGE>   29

joint venture, sales agency or principal and agent. Neither party is the agent
of the other, and neither party may hold itself out as such to any other party.
All financial obligations associated with each party's business shall be the
sole responsibility of such party.

         12.8     PUBLIC ANNOUNCEMENTS.

                  The form and content of any public announcement to be made by
one party regarding this Agreement, or the subject matter contained herein,
shall be subject to the prior written consent of the other party (which consent
shall not be unreasonably withheld, delayed or conditioned), except as may be
required by applicable law (including, without limitation, disclosure
requirements of the SEC, NYSE, NASDAQ, AMEX or any other stock exchange) in
which event the other party shall endeavor to give the other party reasonable
advance notice and review of any such disclosure.

         12.9     COUNTERPARTS.

                  This Agreement shall become binding when any one or more
counterparts hereof, individually or taken together, shall bear the signatures
of each of the parties hereto. This Agreement may be executed in any number of
counterparts, each of which shall be deemed an original as against the party
whose signature appears thereon, but all of which taken together shall
constitute but one and the same instrument.

         12.10 FORCE MAJEURE.

                  Neither party shall be liable to the other party for any
failure to perform as required by this Agreement (other than the obligation to
pay money) if the failure to perform is due to circumstances reasonably beyond
such party's control including, without limitation, acts of God, civil disorders
or commotions, acts of aggression, fire, explosions, floods, drought, war,
sabotage, embargo, utility failures, material shortages, labor disturbances, a
national health emergency, or appropriations of property. A party whose
performance is affected by a force majeure event shall take prompt action using
its reasonable best efforts to remedy the effects of the force majeure event.

         12.11 INTERPRETATION.

                  The parties hereto acknowledge and agree that: (a) each party
and its representatives have reviewed and negotiated the terms and provisions of
this Agreement and have contributed to its revision; and (b) the terms and
provisions of this Agreement shall be construed fairly as to each party hereto
and not in favor of or against either party regardless of which party was
generally responsible for the preparation or drafting of this Agreement.

                                       26
<PAGE>   30

         12.12 CERTAIN EXPENSES AND COMMISSIONS.

                  Except as otherwise expressly set forth in this Agreement, the
parties hereto shall each pay all their costs and expenses, including legal and
accounting fees, incurred in connection with the preparation, negotiation,
execution and delivery of this Agreement, respective brokerage fees, commissions
and finder's fees, if any, and shall indemnify and hold the other harmless from
and against any and all other claims or liabilities for such costs and expenses,
brokerage fees, commissions and finder's fees incurred by reason of any action
taken by any such party.

         12.13 THIRD PARTY BENEFICIARIES.

                  This Agreement is not intended to confer upon any non-party
rights or remedies hereunder, except as may be received or created as part of a
valid assignment.

         12.14 COVENANT NOT TO PROMOTE COMPETING PRODUCT.

                  NOVAVAX shall not (and shall not assist any third party to)
manufacture, market, sell, or promote in the Territory any product directly
competitive with any of the Products during the Term of this Agreement.

         12.15 HEADINGS.

                  The headings contained in this Agreement are for reference
purposes only and shall not affect in any way the meaning or interpretation of
this Agreement.

                            [SIGNATURE PAGES FOLLOW]

                                       27
<PAGE>   31

         IN WITNESS WHEREOF, the parties have duly executed this Exclusive
License and Distribution Agreement as of the first date written above.

                                     KING PHARMACEUTICALS, INC.

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

                                     NOVAVAX, INC.

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

<PAGE>   32

                                     ANNEX I

                                   DEFINITIONS

                  "ACT" shall mean the United States Federal Food, Drug and
Cosmetic Act, as it may be amended from time to time[, and corresponding laws in
the Territory].

                  "ADDITIONAL EXCLUSIVITY RIGHTS" shall have the meaning set
forth in Section 7.1(b).

                  "AFFILIATE(s)" shall mean, with respect to any Person, any
other Person that directly, or indirectly through one or more intermediaries,
controls, is controlled by or is under common control with, such Person. A
Person shall be regarded as in control of another Person if such Person owns, or
directly or indirectly controls, more than fifty percent (50%) of the voting
securities (or comparable equity interests) or other ownership interests of the
other Person, or if such Person directly or indirectly possesses the power to
direct or cause the direction of the management or policies of the other Person,
whether through the ownership of voting securities, by contract or any other
means whatsoever, provided, however, that, for purposes of this Agreement, the
term "Affiliate" shall not include subsidiaries in which a party or its
Affiliates owns a majority of the ordinary voting power to elect a majority of
the Board of Directors, but is restricted from electing such majority by
contract or otherwise, until such time as such restrictions are no longer in
effect.

                  "AGREEMENT" shall mean this Agreement, together with all
appendices, exhibits and schedules referenced herein or attached hereto, and as
the same may be amended or supplemented from time to time hereafter pursuant to
the provisions hereof.

                  "BINDING QUARTERLY FORECAST" shall have the meaning set forth
in Section 3.2.

                  "CALENDAR QUARTER" shall mean each three (3) month period
commencing on the first (1st) day of January, April, July or October, as the
case may be, during the Term.

                  "CHANGE OF CONTROL" shall mean any sale of voting securities
or sale of assets (whether by sale, merger, consolidation, share exchange or
otherwise in one transaction or a series of transactions) in or by a party
hereto that, directly or indirectly, results in any third party becoming the
beneficial owner, directly or indirectly, of securities or assets of such first
party representing over fifty percent (50%) of the combined voting power of such
Person's then outstanding securities or over fifty percent (50%) of such first
party's total assets.

<PAGE>   33

                  "COMMERCIALLY REASONABLE EFFORTS" shall mean efforts and
resources normally used by a party for a product owned by it or to which it has
rights, which is of similar market potential at a similar state in its
development or product life, taking into account issues of safety, efficacy,
product profile, the competitiveness of the marketplace, the proprietary
position of the product, the regulatory structure involved, the profitability of
the applicable products, and other relevant commercial factors.

                  "CONFIDENTIALITY AGREEMENTS" shall have the meaning set forth
in Section 8.

                  "CONFIDENTIAL OR PROPRIETARY INFORMATION" shall have the
meaning set forth in Section 8.

                  "COST OF PRODUCTS" shall mean an amount equal to the fully
allocated costs of the Products incurred by NOVAVAX in connection with
manufacturing the Products, and NOVAVAX' performance of this Agreement, in
accordance with GAAP.

                  "CURRENT GOOD MANUFACTURING PRACTICES" shall mean the current
standards for the manufacture of biologicals, as set forth in the Act and
applicable regulations and guidelines promulgated thereunder or successors
thereto, as shall be in effect from time to time during the Term.

                  "EFFECTIVE DATE" shall have the meaning set forth in the
PREAMBLE of this Agreement.

                  "ESTRASORB" shall mean the product described in Phase III
Clinical Studies.

                  "EXTENDED PROMOTION TERM" shall have the meaning set forth in
Section 7.1(b).

                  "FDA" shall mean the United States Food and Drug
Administration or any successor entity thereto.

                  "GAAP" shall mean United States generally accepted accounting
principles.

                  "INDEMNITEE" shall have the meaning set forth in Section 9.3.

                  "INDEMNITOR" shall have the meaning set forth in Section 9.3.

                                  ANNEX I - 2
<PAGE>   34

                  "INITIAL TERM" shall have the meaning set forth in Section
7.1(a).

                  "KING" shall have the meaning set forth in the PREAMBLE of
this Agreement.

                  "KNOW-HOW" shall mean all tangible and intangible technical
and other information including, but not limited to ideas, conceptions,
reductions-to-practice, discoveries, data, designs, chemical structures,
formulae, materials, intermediates, inventions (whether patentable or not),
methods, models, prototypes, samples, works (whether copyrightable or not),
assays, research plans, procedures, designs, experiments, tests, results of
experimentation and testing (including results of research or development),
processes (including manufacturing processes, uses, specifications and
techniques), laboratory records, note books, chemical, pharmacological,
toxicological, clinical, analytical and quality control data, trial data, case
report forms, data analyses, reports, manufacturing data, summaries and
information contained in submissions to and from ethical committees and
regulatory authorities, which relates to or concerns a Product. Know-How
includes all documents and copies thereof (whether in written, machine-readable,
physical or graphic form) and other things (such as prototypes, materials,
samples, models, etc.) which contain, embody or refer to the Know-How. Such
information, documents or things will not be excluded from being Know-How
hereunder by reason of the fact that they become available to the public only
through a wrongful act or omission to act of a party hereto or a sublicensee or
distributor of a party hereto. The fact that an item is known to the public
shall not be taken to exclude the possibility that a compilation including the
item, and/or a development relating to the item, is (and remains) not known to
the public. Know-How includes, but is not limited to, any and all rights that
protect the Know-how, such as copyrights software, rights, trade secret rights,
database rights and/or design rights.

                  "MODEL CLAIMS" shall mean final approval by the FDA of
Estrasorb as an estrogen hormone replacement therapy prescription product.

                  "NDA" shall mean the new drug applications related to the
Products, submitted to the FDA pursuant to provisions of the Act and applicable
regulations related thereto.

                  "NET SALES" shall mean all gross revenue actually received by
a party from sales of the Products, less (a) credits for refunds and returns,
(b) sales, use and similar taxes billed by such party to its customers and
required to be paid to the appropriate taxing authorities by such party; (c)
discounts, allowances and commissions paid or allowed by a party on sales of the

                                  ANNEX I - 3
<PAGE>   35

Products, and (c) amounts paid by such party and billed through to such party's
customers for insurance, shipping and similar charges.

                  "NON-BINDING FORECASTS" shall have the meaning set forth in
Section 3.2.
                  "NON-SERIOUS ADVERSE EVENT" shall mean any adverse drug
experience associated with the use of the Products in humans, whether or not
considered drug related, which is not a Serious Adverse Event.

                  "NOVAVAX" shall have the meaning set forth in the PREAMBLE.

                  "NOVAVAX GUIDELINES" shall have the meaning set forth in
Section 2.3(a).

                  "NOVAVAX TRADEMARK" shall mean the federally registered
trademark ESTRASORB(R), and any other related trademark or servicemark
containing the word "ESTRASORB", and any other trademark or service mark
(whether registered or unregistered) that NOVAVAX decides to use on or with the
Products or in any promotional material related to any of the Products.

                  "OB/GYN" shall have the meaning set forth in the PREAMBLE of
the Agreement in each case who are authorized by applicable law to prescribe the
Products.

                  "PDMA" shall mean the Prescription Drug Marketing Act, as
amended, and the implementing rules and regulations thereunder.

                  "PERSON" shall mean an individual, corporation, partnership,
limited liability company, trust, business trust, association, joint stock
company, joint venture, pool, syndicate, sole proprietorship, unincorporated
organization, governmental authority, or any other form of entity not
specifically listed herein.

                  "PRIMARY BRAND TRADEMARK" shall have the meaning set forth in
Section 2.3(c).

                  "PRODUCT" shall mean ESTRASORB(TM) and any hormone replacement
therapy pharmaceutical product marketed in the field of women's health including
or using technology or Know-How derived from to ESTRASORB(TM), including but not
limited to products containing a combination of a Product and another
pharmaceutical product; provided that Product shall specifically exclude any
pharmaceutical or related products owned by NOVAVAX as a direct result of the
consummation of the Fielding Acquisition Agreement.

                                  ANNEX I - 4
<PAGE>   36

                  "PRODUCT INITIATION DATE" shall mean the date on which the FDA
provides written approval of the NDA for ESTRASORB(R).

                  "PRODUCT RIGHTS" shall have the meaning set forth in Section
10.2(d).

                  "PRODUCT TECHNICAL COMPLAINTS" shall mean any complaint that
questions the purity, identity, potency or quality of the Products, its
packaging or labeling, the compliance of any batch of the Products with
applicable laws, including the Act, or any complaint that concerns any incident
that causes the Products or their labeling to be mistaken for, or applied to,
another article or any bacteriological contamination, or any significant
chemical, physical, or other change or deterioration in the Products, or any
failure of one or more batches of the Products to meet the Specifications
therefor in the NDA.

                  "PURCHASE PRICE" shall have the meaning set forth in Section
5.1(a).

                  "ROYALTY PAYMENT" shall have the meaning set forth in Section
5.2.

                  "SERIOUS ADVERSE EVENT" shall mean any serious and unexpected
adverse drug experience, as defined by FDA in 21 C.F.R. Section 314.80,
associated with the use of the drug in humans, whether or not considered drug
related.

                  "SOP" shall have the meaning set forth in Section 4.4.

                  "SPECIFICATIONS" shall mean the specifications for the Product
set forth in the NDA for the Product, as such NDA may be amended from time to
time.

                  "TERM" shall have the meaning set forth in Section 7.1(a).

                  "TERRITORY" shall mean anywhere in the world except the United
States, its territories and possessions, the District of Columbia, the
Commonwealth of Puerto Rico, Canada, Italy, the Netherlands, Greece, Switzerland
and Spain.

                  "TRADEMARKS" shall mean the NOVAVAX Trademarks.

                                  ANNEX I - 5
<PAGE>   37

                                 EXHIBIT 2.3(a)

                                   TRADEMARKS

                                    NOVAVAX:

                                  NOVAVAX Logo

                                        i
<PAGE>   38

                               EXHIBIT 2.3(c)(ii)

                            PRIMARY BRAND TRADEMARKS

                                  ESTRASORB(TM)

                                       ii<PAGE>   1

                                                                    EXHIBIT 4.12

                                                                  EXECUTION COPY

                             XO COMMUNICATIONS, INC.

                                       TO

                    U.S. TRUST COMPANY, NATIONAL ASSOCIATION

                                     Trustee

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

                                    Indenture

                          Dated as of January 12, 2001

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

                                  $517,500,000

                 5 3/4% Convertible Subordinated Notes Due 2009

<PAGE>   2

<TABLE>
<CAPTION>
                                TABLE OF CONTENTS

<S>                                                                                                   <C>
RECITALS OF THE COMPANY.................................................................................1

                                  ARTICLE ONE.
             DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION

SECTION 101.       Definitions..........................................................................1
SECTION 102.       Compliance Certificates and Opinions................................................15
SECTION 103.       Form of Documents Delivered to Trustee..............................................15
SECTION 104.       Acts of Holders; Record Dates.......................................................16
SECTION 105.       Notices, Etc., to Trustee and Company...............................................18
SECTION 106.       Notice to Holders; Waiver...........................................................18
SECTION 107.       Application of Trust Indenture Act..................................................18
SECTION 108.       Effect of Headings and Table of Contents............................................19
SECTION 109.       Successors and Assigns..............................................................19
SECTION 110.       Separability Clause.................................................................19
SECTION 111.       Benefits of Indenture...............................................................19
SECTION 112.       Governing Law.......................................................................19
SECTION 113.       Legal Holidays......................................................................19

                                  ARTICLE TWO.
                                SECURITIES FORMS

SECTION 201.       Forms Generally.....................................................................20
SECTION 202.       Form of Face of Security............................................................20
SECTION 203.       Form of Reverse of Security.........................................................24
SECTION 204.       Additional Provisions Required in Global Security...................................35
SECTION 205.       Form of Trustee's Certificate of Authentication.....................................36

                                 ARTICLE THREE.
                                 THE SECURITIES

SECTION 301.       Title and Terms.....................................................................36
SECTION 302.       Denominations.......................................................................37
SECTION 303.       Execution, Authentication, Delivery and Dating......................................38
SECTION 304.       Temporary Securities................................................................38
SECTION 305.       Registration, Registration of Transfer, Exchange and Conversion.....................39
SECTION 306.       Mutilated, Destroyed, Lost and Stolen Securities....................................44
SECTION 307.       Payment of Interest; Interest Rights Preserved......................................44
SECTION 308.       Persons Deemed Owners...............................................................45
SECTION 309.       Cancellation........................................................................46
SECTION 310.       Computation of Interest.............................................................46
SECTION 311.       CUSIP and ISIN Numbers..............................................................46
</TABLE>

                                       i
<PAGE>   3

<TABLE>
<CAPTION>
                                  ARTICLE FOUR.
                           SATISFACTION AND DISCHARGE

<S>                                                                                                   <C>
SECTION 401.       Satisfaction and Discharge of Indenture.............................................46
SECTION 402.       Application of Trust Money..........................................................47

                                  ARTICLE FIVE.
                                    REMEDIES

SECTION 501.       Events of Default...................................................................48
SECTION 502.       Acceleration of Maturity; Rescission and Annulment..................................49
SECTION 503.       Collection of Indebtedness and Suits for Enforcement by Trustee.....................50
SECTION 504.       Trustee May File Proofs of Claim....................................................51
SECTION 505.       Trustee May Enforce Claims Without Possession of Securities.........................52
SECTION 506.       Application of Money Collected......................................................52
SECTION 507.       Limitation on Suits.................................................................52
SECTION 508.       Unconditional Right of Holders to Receive Principal, Premium and Interest...........53
SECTION 509.       Restoration of Rights and Remedies..................................................53
SECTION 510.       Rights and Remedies Cumulative......................................................53
SECTION 511.       Delay or Omission Not Waiver........................................................54
SECTION 512.       Control by Holders..................................................................54
SECTION 513.       Waiver of Past Defaults.............................................................54
SECTION 514.       Undertaking for Costs...............................................................55
SECTION 515.       Waiver of Stay or Extension Laws....................................................55

                                  ARTICLE SIX.
                                   THE TRUSTEE

SECTION 601.       Certain Duties and Responsibilities.................................................55
SECTION 602.       Notice of Defaults..................................................................55
SECTION 603.       Certain Rights of Trustee...........................................................56
SECTION 604.       Not Responsible for Recitals or Issuance of Securities..............................57
SECTION 605.       May Hold Securities.................................................................57
SECTION 606.       Money Held in Trust.................................................................57
SECTION 607.       Compensation and Reimbursement......................................................57
SECTION 608.       Disqualification; Conflicting Interests.............................................58
SECTION 609.       Corporate Trustee Required; Eligibility.............................................58
SECTION 610.       Resignation and Removal; Appointment of Successor...................................58
SECTION 611.       Acceptance of Appointment by Successor..............................................59
SECTION 612.       Merger, Conversion, Consolidation or Succession to Business.........................60
SECTION 613.       Preferential Collection of Claims Against the Company...............................60
SECTION 614.       Appointment of Authenticating Agent.................................................60
</TABLE>

                                       ii

<PAGE>   4

<TABLE>
<CAPTION>

                                 ARTICLE SEVEN.
              HOLDERS' LISTS AND REPORTS BY TRUSTEE AND THE COMPANY

<S>                                                                                                   <C>
SECTION 701.       Company to Furnish Trustee Names and Addresses of Holders...........................62
SECTION 702.       Preservation of Information; Communications to Holders..............................62
SECTION 703.       Reports by Trustee..................................................................62
SECTION 704.       Reports by Company..................................................................63
SECTION 705.       Officers' Certificate with Respect to Change in Interest Rates......................63

                                 ARTICLE EIGHT.
                           MERGER, CONSOLIDATION, ETC.

SECTION 801.       Mergers, Consolidations and Certain Sales of Assets.................................63
SECTION 802.       Successor Substituted...............................................................64

                                  ARTICLE NINE.
                             SUPPLEMENTAL INDENTURES

SECTION 901.       Supplemental Indentures Without Consent of Holders..................................64
SECTION 902.       Supplemental Indentures with Consent of Holders.....................................65
SECTION 903.       Execution of Supplemental Indentures................................................65
SECTION 904.       Effect of Supplemental Indentures...................................................66
SECTION 905.       Conformity with Trust Indenture Act.................................................66
SECTION 906.       Reference in Securities to Supplemental Indentures..................................66

                                  ARTICLE TEN.
                                    COVENANTS

SECTION 1001.      Payment of Principal, Premium and Interest..........................................66
SECTION 1002.      Maintenance of Office or Agency.....................................................66
SECTION 1003.      Money for Security Payments to be Held in Trust.....................................67
SECTION 1004.      Existence...........................................................................68
SECTION 1005.      Maintenance of Properties and Insurance.............................................68
SECTION 1006.      Provision of Financial Information..................................................69
SECTION 1007.      Rule 144A Information Requirement...................................................69
SECTION 1008.      Statement by Officers as to Default.................................................69
SECTION 1009.      Waiver of Certain Covenants and Obligations.........................................69

                                 ARTICLE ELEVEN.
                       DEFEASANCE AND COVENANT DEFEASANCE

SECTION 1101.      Company's Option to Effect Defeasance or Covenant Defeasance........................70
SECTION 1102.      Defeasance and Discharge............................................................70
SECTION 1103.      Covenant Defeasance.................................................................71
SECTION 1104.      Conditions to Defeasance or Covenant Defeasance.....................................71
SECTION 1105.      Deposited Money and U.S. Government Obligations to Be Held in Trust; Other
                   Miscellaneous Provisions............................................................73
SECTION 1106.      Reinstatement.......................................................................73
</TABLE>

                                      iii
<PAGE>   5

<TABLE>
<S>                                                                                                   <C>
SECTION 1107.      Repayment to Company................................................................74

                                 ARTICLE TWELVE.
                       REPURCHASE AT THE OPTION OF HOLDERS

SECTION 1201.      Right to Require Repurchase.........................................................74
SECTION 1202.      Conditions to the Company's Election to Pay the Repurchase Price in Class A Common
                   Stock of the Company................................................................77
SECTION 1203.      Consolidation, Merger, Etc..........................................................77

                                ARTICLE THIRTEEN.
                            CONVERSION OF SECURITIES

SECTION 1301.      Applicability of Article............................................................78
SECTION 1302.      Right of Holders to Convert Securities into Class A Common Stock....................78
SECTION 1303.      Issuance of Shares of Class A Common Stock on Conversions...........................79
SECTION 1304.      No Payment or Adjustment for Interest or Dividends..................................80
SECTION 1305.      Adjustment of Conversion Rate.......................................................80
SECTION 1306.      No Fractional Shares to be Issued...................................................87
SECTION 1307.      Preservation of Conversion Rights upon Consolidation, Merger, Sale or Conveyance....87
SECTION 1308.      Notice to Holders of the Securities Prior to Taking Certain Types of Action.........88
SECTION 1309.      Covenants to Reserve Shares for Issuance on Conversion of Securities................89
SECTION 1310.      Compliance with Governmental Requirements...........................................89
SECTION 1311.      Payment of Taxes upon Certificates for Shares Issued upon Conversion................90
SECTION 1312.      Trustee's Duties with Respect to Conversion Provisions..............................90

                                ARTICLE FOURTEEN.
                        TERMINATION OF CONVERSION RIGHTS

SECTION 1401.      Expiration of Conversion Rights.....................................................90
SECTION 1402.      Election to Terminate; Press Release................................................91
SECTION 1403.      Conversion Expiration Date..........................................................91
SECTION 1404.      Make-Whole Payment..................................................................91
SECTION 1405.      Deposit of Make Whole Payment.......................................................92

                                ARTICLE FIFTEEN.
                           SUBORDINATION OF SECURITIES

SECTION 1501.      Securities Subordinated to Senior Indebtedness......................................92
SECTION 1502.      No Payment on Securities in Certain Circumstances...................................92
SECTION 1503.      Securities Subordinated to Prior Payment of All Senior Indebtedness on Dissolution,
                   Liquidation or Reorganization.......................................................94
SECTION 1504.      Securityholders to Be Subrogated to Rights of Holders of Senior Indebtedness........95
SECTION 1505.      Obligations of the Company Unconditional............................................95
</TABLE>

                                       iv

<PAGE>   6

<TABLE>
<S>                                                                                                   <C>
SECTION 1506.      Trustee Entitled To Assume Payments Not Prohibited in Absence of Notice.............96
SECTION 1507.      Application by Trustee of Assets Deposited with It..................................96
SECTION 1508.      Subordination Rights Not Impaired by Acts or Omissions of the Company or Holders of
                   Senior Indebtedness.................................................................96
SECTION 1509.      Securityholders Authorize Trustee to Effectuate Subordination of Securities.........97
SECTION 1510.      Right of Trustee to Hold Senior Indebtedness........................................97
SECTION 1511.      Article Fifteen Not to Prevent Events of Default....................................97
SECTION 1512.      No Fiduciary Duty of Trustee to Holders of Senior Indebtedness......................97
</TABLE>

                                       v

<PAGE>   7

XO COMMUNICATIONS, INC.

Reconciliation and tie between Trust Indenture Act of
1939 and Indenture, dated as of January 12, 2001

<TABLE>
<CAPTION>
Trust Indenture Act Section                               Indenture Section
<S>         <C>                                               <C>
Section 310(a)(1)........................................       607
           (b)...........................................       607, 608
Section 312(c) ..........................................       701
Section 313(a) ..........................................       702
           (c)...........................................       702
Section 314(a) ..........................................       703
           (a)(4)........................................       1006
           (c)(1)........................................       102
           (c)(2)........................................       102
           (e)...........................................       102
Section 315(b) ..........................................       601
Section 316(a) (last sentence)...........................       101 ("Outstanding")
           (a)(1)(A).....................................       502, 512
           (a)(1)(B).....................................       513
           (b)...........................................       508
Section 317(a) (1).......................................       503
           (a)(2)........................................       504
Section 318(a) ..........................................       111
           (c)...........................................       111

</TABLE>

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

NOTE: This reconciliation and tie shall not, for any purpose, be deemed to be a
part of the Indenture.

        Reference is also made to Section 318(c) of the Trust indenture Act of
1939, which provides that the provisions of Section 310 to and including Section
317 of the Trust Indenture Act of 1939 are a part of and govern every qualified
indenture, whether or not physically contained therein.

                                       vi
<PAGE>   8

        INDENTURE, dated as of January 12, 2001, between XO COMMUNICATIONS,
INC., a Delaware corporation (hereinafter called the "Company"), having its
principal office at 11111 Sunset Hills Drive, Reston, VA 20190 and U.S. Trust
Company, National Association, a corporation duly organized and existing under
the laws of the United States, as Trustee hereunder (hereinafter called the
"Trustee").

                             RECITALS OF THE COMPANY

        The Company has duly authorized the creation of an issue of $517,500,000
aggregate principal amount of its 5 3/4% Convertible Subordinated Notes due 2009
(the "Securities") of substantially the tenor and amount hereinafter set forth,
and to provide therefor the Company has duly authorized the execution and
delivery of this Indenture. The Securities shall be subordinate in right of
payment to the existing and future Senior Indebtedness (as hereinafter defined)
of the Company to the extent provided in Article Fifteen of this Indenture.

        This Indenture is subject to the provisions of the Trust Indenture Act
of 1939, as amended, that are deemed to be incorporated into this Indenture and
shall, to the extent applicable, be governed by such provisions.

        All things necessary to make the Securities, when executed by the
Company and authenticated and delivered hereunder and duly issued by the
Company, the valid obligations of the Company, and to make this Indenture a
valid agreement of the Company, in accordance with its terms, have been done.

        NOW, THEREFORE, THIS INDENTURE WITNESSETH:

        For and in consideration of the premises and the purchase of the
Securities by the Holders thereof, it is mutually covenanted and agreed, for the
equal and proportionate benefit of all Holders of the Securities, as follows:

                                  ARTICLE ONE.

             DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION

SECTION 101.  Definitions.

        For all purposes of this Indenture, except as otherwise expressly
provided or unless the context otherwise requires:

                (1) the terms defined in this Article have the meanings assigned
        to them in this Article and include the plural as well as the singular;

                (2) all other terms used herein which are defined in the Trust
        Indenture Act, either directly or by reference therein, have the
        meanings assigned to them therein;

                                       1

<PAGE>   9

                (3) all accounting terms not otherwise defined herein have the
        meanings assigned to them in accordance with generally accepted
        accounting principles (whether or not such is indicated herein) and,
        except as otherwise herein expressly provided, the term "GAAP" or
        "generally accepted accounting principles" with respect to any
        computation required or permitted hereunder shall mean such accounting
        principles as are generally accepted as consistently applied by the
        Company at the date of such computation; and

                (4) the words "herein", "hereof" and "hereunder" and other words
        of similar import refer to this Indenture as a whole and not to any
        particular Article, Section or other subdivision.

        Certain terms, used principally in Article Six, are defined in that
Article.

        "Act", when used with respect to any Holder, has the meaning specified
in Section 104.

        "Affiliate" of any specified Person means any other Person directly or
indirectly controlling or controlled by or under direct or indirect common
control with such specified Person. For the purposes of this definition,
"control" when used with respect to any specified Person means the power to
direct the management and policies of such Person, directly or indirectly,
whether through the ownership of voting securities, by contract or otherwise;
and the terms "controlling" and "controlled" have meanings correlative to the
foregoing.

        "Agent Member" means any member of, or participant in, the depository.

        "Applicable Procedures" means, with respect to any transfer or
transaction involving a Global Security or beneficial interest therein, the
rules and procedures of the Depositary for such Security, Euroclear and Cedel,
in each case to the extent applicable to such transaction and as in effect from
time to time.

        "Authenticating Agent" has the meaning set forth in Section 614 hereof.

        "Authorized Newspaper" means a newspaper, printed in the English
language or in an official language of the country of publication, customarily
published on each business day in the country of publication, whether or not
published on Saturdays, Sundays or holidays, and of general circulation in each
place in connection with which the term is used or in the financial community of
each such place. Whenever successive publications are required to be made in
Authorized Newspapers, the successive publications may be made in the same or in
different Authorized Newspapers in the same city meeting the foregoing
requirements and in each case on any business day in the country of publication.

        "Board of Directors" means either the board of directors of the Company
or any duly authorized committee of that Board.

        "Board Resolution" means a copy of a resolution certified by the
Secretary or an Assistant Secretary of the Company to have been duly adopted by
the Board

                                       2
<PAGE>   10

of Directors and to be in full force and effect on the date of such
certification, and delivered to the Trustee.

        "Business Day" means each Monday, Tuesday, Wednesday, Thursday and
Friday which is not a day on which banking institutions in The Borough of
Manhattan, The City of New York, New York are authorized or obligated by law or
executive order to close.

        "Capital Lease Obligation" of any Person means the obligation to pay
rent or other payment amounts under a lease of (or other Indebtedness
arrangements conveying the right to use) real or personal property of such
Person which is required to be classified and accounted for as a capital lease
or a liability on the face of a balance sheet of such Person in accordance with
generally accepted accounting principles. The stated maturity of such obligation
shall be the date of the last payment of rent or any other amount due under such
lease prior to the first date upon which such lease may be terminated by the
lessee without payment of a penalty. The principal amount of such obligation
shall be the capitalized amount thereof that would appear on the face of a
balance sheet of such Person in accordance with generally accepted accounting
principles.

        "Capital Stock" of any Person means any and all shares, interests,
participations or other equivalents (however designated) of corporate stock or
other equity participations, including partnership interests, whether general or
limited, of such Person.

        "Cedel" means Cedel Bank, S.A. (or any successor securities clearing
agency).

        A "Change of Control" will be deemed to have occurred at such time as
either:

                (1)     any Person or any Persons acting together that would
constitute a "group" for purposes of Section 13(d) of the Exchange Act, or any
successor provision thereto (other than Eagle River, Mr. Craig O. McCaw and
their respective Affiliates or an underwriter engaged in a firm commitment
underwriting on behalf of the Company), shall beneficially own (within the
meaning of Rule 13d-3 under the Exchange Act, or any successor provision
thereto) more than 50% of the aggregate voting power of all classes of Voting
Stock of the Company; or

                (2)     neither Mr. Craig O. McCaw nor any person designated by
him to the Company as acting on his behalf shall be a director of the Company;
or

                (3)     during any period of two consecutive years, individuals
who at the beginning of such period constituted the Board of Directors (together
with any new directors whose election by the Board of Directors or whose
nomination for election by the shareholders of the Company was proposed by a
vote of a majority of the directors of the Company then still in office who were
either directors at the beginning of such period or whose election or nomination
for election was previously so approved) cease for any reason to constitute a
majority of the Board of Directors then in office.

                                       3
<PAGE>   11

        "Class A Common Stock" means the Company's Class A common stock, par
value $.02 per share.

        "Class B Common Stock" means the Company's Class B common stock, par
value $.02 per share.

        "Commission" means the Securities and Exchange Commission, as from time
to time constituted, created under the Exchange Act, or, if at any time after
the execution of this instrument such Commission is not existing and performing
the duties now assigned to it under the Trust Indenture Act, then the body
performing such duties at such time.

        "Common Stock" means the Class A Common Stock and Class B Common Stock
collectively.

        "Company" means the Person named as the "Company" in the first paragraph
of this instrument until a successor Person shall have become such pursuant to
the applicable provisions of this Indenture and thereafter "Company" shall mean
such successor Person.

        "Company Request" or "Company Order" means a written request or order
signed in the name of the Company by (i) the Chief Executive Officer, the
President, an Executive Vice President or a Vice President of the Company, and
(ii) the Treasurer, Assistant Treasurer or Secretary of the Company, and
delivered to the Trustee.

        "Conversion Price" shall equal $1,000 divided by the Conversion Rate
(rounded to the nearest 4th decimal place, with $0.00005 or more being rounded
upward).

        "Conversion Rate" has the meaning set forth in Section 1302 hereof.

        "Conversion Termination Date" has the meaning set forth in Section 1401
hereof.

        "Corporate Trust Office" means the principal office of the U.S. Trust
Company, National Association in the Borough of Manhattan, The City of New York,
New York, at which at any particular time its corporate trust business shall be
administered, which at the date hereof is located at 114 West 47th Street, New
York, New York 10036.

        "corporation" means a corporation, association, company, limited
liability company, joint-stock company or business trust.

        "Credit Agreement" means the Credit and Guaranty Agreement, dated as of
February 3, 2000, between the Company and the several lenders listed therein, as
amended or supplemented from time to time.

                                       4
<PAGE>   12

        "Current Market Price" of Class A Common Stock of the Company for any
day means the last reported per share sale price, regular way on such day, or,
if no sale takes place on such day, the average of the reported closing per
share bid and asked prices on such day, regular way, in either case as reported
on the NASDAQ National Market or, if such Class A Common Stock is not quoted or
admitted to trading on such quotation system, on the principal national
securities exchange or quotation system on which such Class A Common Stock may
be listed or admitted to trading or quoted, or, if not listed or admitted to
trading or quoted on any national securities exchange or quotation system, the
average of the closing per share bid and asked prices of such Class A Common
Stock on the over-the-counter market on the day in question as reported by the
National Quotation Bureau Incorporated, or similar generally accepted reporting
service, or, if not so available in such manner, as furnished by any NASDAQ
member firm selected from time to time by the Board of Directors of the Company
for that purpose, or, if not so available in such manner, as otherwise
determined in good faith by the Board of Directors of the Company.

        "Default" means an event that with the passing of time or the giving of
notice or both shall constitute an Event of Default.

        "Defaulted Interest" has the meaning set forth in Section 307 hereof.

        "Depositary" means, with respect to the Securities issuable or issued in
whole or in part in the form of one or more Global Securities, DTC for so long
as it shall be a clearing agency registered under the Exchange Act, or such
successor (which shall be a clearing agency registered under the Exchange Act)
as the Company shall designate from time to time in an Officers' Certificate
delivered to the Trustee.

        A "Designated Event" shall be deemed to have occurred upon a Change of
Control or a Termination of Trading; provided, that no Designated Event relating
to a Termination of Trading shall be deemed to have occurred prior to the
termination of the Credit Agreement or a receipt of a Waiver under the Credit
Agreement.

        "Designated Event Offer" means a written offer (the "Offer") sent by the
Company by first class mail, postage prepaid, to each Holder at his address
appearing in the Security Register on the date of the Offer offering to purchase
all duly tendered Securities at the purchase price specified in such Offer (as
determined pursuant to this Indenture). Unless otherwise required by applicable
law, the Offer shall specify an expiration date (the "Expiration Date") of the
Designated Event Offer which shall be, subject to any contrary requirements of
applicable law, not less than 30 days or more than 60 days after the date of
such Offer and a settlement date (the "Designated Event Payment Date") for
purchase of Securities within five Business Days after the Expiration Date. The
Company shall notify the Trustee at least 15 Business Days (or such shorter
period as is acceptable to the Trustee) prior to the mailing of the Offer of the
Company's obligation to make a Designated Event Offer, and the Offer shall be
mailed by the Company or, at the Company's request, by the Trustee in the name
and at the expense of the Company. The Offer shall contain information
concerning the business of the Company and its Subsidiaries which the Company in
good faith believes will enable such Holders to make an informed decision with
respect to the Designated Event Offer (which at a

                                       5
<PAGE>   13

minimum will include (i) the most recent annual and quarterly financial
statements and "Management's Discussion and Analysis of Financial Condition and
Results of Operations" contained in the documents required to be filed with the
Trustee pursuant to this Indenture (which requirements may be satisfied by
delivery of such documents together with the Offer), (ii) a description of
material developments in the Company's business subsequent to the date of the
latest of such financial statements referred to in clause (i) (including a
description of the events requiring the Company to make the Designated Event
Offer), (iii) if applicable, appropriate pro forma financial information
concerning the Designated Event Offer and the events requiring the Company to
make the Designated Event Offer and (iv) any other information required by
applicable law to be included therein). The Offer shall contain all instructions
and materials necessary to enable such Holders to tender Securities pursuant to
the Designated Event Offer. The Offer shall also state:

                (a)     the Section of this Indenture pursuant to which the
        Designated Event Offer is being made;

                (b)     the Expiration Date and the Designated Event Payment
                        Date;

                (c)     the purchase price to be paid by the Company for each
        $1,000 aggregate principal amount of Securities accepted for payment (as
        specified pursuant to this Indenture) (the "Purchase Price");

                (d)     that the Holder may tender all or any portion of the

        Securities registered in the name of such Holder and that any portion of
        a Security tendered must be tendered in an integral multiple of $1,000
        principal amount;

                (e)     the place or places where Securities are to be
        surrendered for tender pursuant to the Designated Event Offer;

                (f)     that interest on any Security not duly tendered pursuant
        to the Designated Event Offer will continue to accrue;

                (g)     that on the Designated Event Payment Date the Purchase

        Price will become due and payable upon each Security duly tendered
        pursuant to the Designated Event Offer and that interest thereon shall
        cease to accrue on and after the Designated Event Payment Date;

                (h)     that each Holder electing to tender a Security pursuant
        to the Designated Event Offer will be required to surrender such
        Security at the place or places specified in the Offer prior to the
        close of business on the Expiration Date (such Security being, if the
        Company or the Trustee so requires, duly endorsed by, or accompanied by
        a by a written instrument of transfer in form satisfactory to the
        Company and the Trustee duly executed by, the Holder thereof or his
        attorney duly authorized in writing), together, if the Designated Event
        Payment Date is after a Regular Record Date and prior to the ensuing
        Interest Payment Date, with payment in New York Clearing House or other
        funds acceptable to the Company of the interest payable on such Interest
        Payment Date;

                                       6
<PAGE>   14

                (i)     that Holders will be entitled to withdraw all or any
        portion of Securities tendered if the Company (or its Paying Agent)
        receives, not later than the close of business on the Expiration Date,
        a telegram, telex, facsimile transmission or letter setting forth the
        name of the Holder, the principal amount of the Security the Holder
        tendered, the certificate number of the Security the Holder tendered
        and a statement that such Holder is withdrawing all or a portion of his
        tender;

                (j)     that the Company shall purchase all Securities duly
        tendered;

                (k)     that in the case of any Holder whose Security is
        purchased only in part, the Company shall execute, and the Trustee
        shall authenticate and deliver to the Holder of such Security without
        service charge, a new Security or Securities, of any authorized
        denomination as requested by such Holder, in an aggregate principal
        amount equal to and in exchange for the unpurchased portion of the
        Security so tendered; and

                (l)     the CUSIP number or numbers of the Securities offered to
        be purchased by the Company pursuant to the Designated Event Offer.

Any Designated Event Offer shall be governed by and effected in accordance with
the Offer for such Designated Event Offer. References in this Indenture to
"principal" shall be deemed to include, without duplication, the purchase price
payable in connection with a Designated Event Offer, unless the context
otherwise requires.

        "Designated Event Payment Date" has the meaning set forth in the
definition of "Designated Event Offer" in this Section 101.

        "Designated Senior Indebtedness" means obligations of the Company under
any particular Senior Indebtedness in respect of which the instrument creating
or evidencing the same or the assumption or guarantee thereof, or related
agreements or documents to which the Company is a party, expressly provides that
such indebtedness shall be Designated Senior Indebtedness for purposes of the
Indenture. The instrument, agreement or other document evidencing any Designated
Senior Indebtedness may place limitations and conditions on the right of such
Senior Indebtedness to exercise the rights of Designated Senior Indebtedness.

        "DTC" means The Depository Trust Company.

        "Eagle River" means Eagle River Investments, L.L.C., a limited liability
company formed under the laws of the State of Washington.

        "Euroclear" means the Euroclear Clearance System (or any successor
securities clearing agency).

        "Event of Default" has the meaning specified in Section 501.

        "Exchange Act" means the Securities Exchange Act of 1934, as amended (or
any successor act) and the rules and regulations thereunder.

                                       7
<PAGE>   15

        "Expiration Date" has the meaning set forth in the definition of
"Designated Event Offer" in this Section 101.

        "Global Security" means a Security in the form prescribed in Section 204
evidencing all or part of the Securities, issued to the Depositary or its
nominee, and registered in the name of such Depositary or its nominee.

        "Guarantee" by any Person means any obligation, contingent or otherwise,
of such Person guaranteeing, or having the economic effect of guaranteeing, any
Indebtedness of any other Person (the "primary obligor") in any manner, whether
directly or indirectly, and including, without limitation, any obligation of
such Person,

        (i) to purchase or pay (or advance or supply funds for the purchase or
payment of) such Indebtedness or to purchase (or to advance or supply funds for
the purchase of) any security for the payment of such Indebtedness,

        (ii) to purchase property, securities or services for the purpose of
assuring the holder of such Indebtedness of the payment of such Indebtedness, or

        (iii) to maintain working capital, equity capital or other financial
statement condition or liquidity of the primary obligor so as to enable the
primary obligor to pay such Indebtedness (and "Guaranteed", "Guaranteeing" and
"Guarantor" shall have meanings correlative to the foregoing); provided,
however, that the Guarantee by any Person shall not include endorsements by such
Person for collection or deposit, in either case, in the ordinary course of
business.

        "Holder" means a Person in whose name a Security is registered in the
Security Register.

        "Incur" means, with respect to any Indebtedness or other obligation of
any Person, to create, issue, incur (by conversion, exchange or otherwise),
assume, Guarantee or otherwise become liable in respect of such Indebtedness or
other obligation including by acquisition of Subsidiaries or the recording, as
required pursuant to generally accepted accounting principles or otherwise, of
any such Indebtedness or other obligation on the balance sheet of such Person
(and "Incurrence", "Incurred", "Incurrable" and "Incurring" shall have meanings
correlative to the foregoing).

        "Indebtedness" means, with respect to any Person, all Obligations,
whether or not contingent, of such Person (i)(a) for borrowed money (including,
but not limited to, any indebtedness secured by a security interest, mortgage or
other lien on the assets of the Company that is (1) given to secure all or part
of the purchase price of property subject thereto, whether given to the vendor
of such property or to another, or (2) existing on property at the time of
acquisition thereof), (b) evidenced by a note, debenture, bond or other written
instrument, (c) under a lease required to be capitalized on the balance sheet of
the lessee under GAAP or under any lease or related document (including a
purchase agreement) that provides that the Company is contractually obligated to
purchase or cause a third party to purchase and thereby guarantee a minimum
residual value of the lease property to the lessor and the Company's obligations
under such lease or related document to purchase or to cause a third party to
purchase such leased property, (d) in respect of letters of credit, bank
guarantees or bankers' acceptances (including

                                       8
<PAGE>   16

reimbursement obligations with respect to any of the foregoing), (e) with
respect to indebtedness secured by a mortgage, pledge, lien, encumbrance, charge
or adverse claim affecting title or resulting in an encumbrance to which the
property or assets of such Person are subject, whether or not the obligation
secured thereby shall have been assumed by or shall otherwise be such Person's
legal liability, (f) in respect of the balance of deferred and unpaid purchase
price of any property or assets, (g) under interest rate or currency swap
agreements, cap, floor and collar agreements, spot and forward contracts and
similar agreements and arrangements; (ii) with respect to any obligation of
others of the type described in the preceding clause (i) or under clause (iii)
below assumed by or guaranteed in any manner by such person or in effect
guaranteed by such person through an agreement to purchase (including, without
limitation, "take or pay" and similar arrangements), contingent or otherwise
(and the obligations of such person under any such assumptions, guarantees or
other such arrangements); and (iii) any and all deferrals, renewals, extensions,
refinancings and refundings of, or amendments, modifications or supplements to,
any of the foregoing.

        "Indenture" means this instrument as originally executed or as it may
from time to time be supplemented or amended by one or more indentures
supplemental hereto entered into pursuant to the applicable provisions hereof.

        "Interest Payment Date" when used with respect to any installment of
interest on a Security means the date specified in such Security on which such
installment of interest is due and payable.

        "Junior Securities" means any Indebtedness of the Company that is at
least as subordinated in right of payment to Senior Indebtedness as the
Securities and has no scheduled installment of principal due, by redemption,
sinking fund payment or otherwise, on or prior to the Stated Maturity of the
Securities.

        "Liquidated Damages" has the meaning set forth in the form of Security
contained in Section 202. Unless the context otherwise requires, references
herein to "interest" on the Securities shall include Liquidated Damages.

        "Material Subsidiary" means, as of any date of determination, a
Subsidiary that is a "significant subsidiary" as defined in Rule 1-02(w) of
Regulation S-X under the Securities Act and the Exchange Act.

        "Maturity", when used with respect to any Security, means the date on
which the principal of such Security becomes due and payable as therein or
herein provided, whether at the Stated Maturity or by declaration of
acceleration, upon required repurchase or otherwise.

        "Measurement Period" has the meaning set forth in Section 1401 hereof.

        "Obligations" means, with respect to any Indebtedness, any principal,
interest, penalties, fees, indemnifications, reimbursements, damages or other
liabilities payable under the documentation governing such Indebtedness.

                                       9
<PAGE>   17

        "Officers' Certificate" means a certificate signed by (i) the Chief
Executive Officer, President, an Executive Vice President or a Vice President,
and (ii) the Treasurer, Assistant Treasurer, Secretary or an Assistant
Secretary, of the Company, and delivered to the Trustee and containing the
statements provided for in Section 102. One of the officers signing an Officers'
Certificate given pursuant to Section 1008 shall be the principal executive,
financial or accounting officer of the Company.

        "Opinion of Counsel" means a written opinion of legal counsel, who may
be counsel for the Company, and who shall be acceptable to the Trustee, and
containing the statements provided for in Section 102.

        "Outstanding", when used with respect to Securities, means, as of the
date of determination, all Securities theretofore authenticated and delivered
under this Indenture, except:

        (i) Securities theretofore cancelled by the Trustee or delivered to the
Trustee for cancellation;

        (ii) Securities for whose payment money in the necessary amount has been
theretofore deposited with the Trustee or any Paying Agent (other than the
Company) in trust or set aside and segregated in trust by the Company (if the
Company shall act as its own Paying Agent) for the Holders of such Securities;
and

        (iii) Securities which have been paid pursuant to Section 306 or in
exchange for or in lieu of which other Securities have been authenticated and
delivered pursuant to this Indenture, other than any such Securities in respect
of which there shall have been presented to the Trustee proof satisfactory to it
that such Securities are held by a bona fide purchaser in whose hands such
Securities are valid obligations of the Company;

provided, however, that in determining whether the Holders of the requisite
principal amount of the Outstanding Securities have given any request, demand,
authorization, direction, notice, consent or waiver hereunder, Securities owned
by the Company or any other obligor upon the Securities or any Affiliate of the
Company or of such other obligor shall be disregarded and deemed not to be
Outstanding, except that, in determining whether the Trustee shall be protected
in relying upon any such request, demand, authorization, direction, notice,
consent or waiver, only Securities which the Trustee knows to be so owned shall
be so disregarded. Securities so owned which have been pledged in good faith may
be regarded as Outstanding if the pledgee establishes to the satisfaction of the
Trustee the pledgee's right so to act with respect to such Securities and that
the pledgee is not the Company or any other obligor upon the Securities or any
Affiliate of the Company or of such other obligor.

        "Paying Agent" means any Person authorized by the Company to pay the
principal of (and premium, if any) or interest on any Securities on behalf of
the Company. The Trustee is hereby authorized by the Company to act as a "Paying
Agent" for the purposes of this Indenture, until such time as the Company
notifies the Trustee in writing that such authorization is revoked.

                                       10
<PAGE>   18

        "Payment Blockage Notice" has the meaning set forth in Section 1502
hereof.

        "Person" means any individual, corporation, partnership, limited
liability company, joint venture, association, joint stock company, trust,
unincorporated organization, government or agency or political subdivision
thereof or any other entity.

        "Predecessor Security" of any particular Security means every previous
Security issued before, and evidencing all or a portion of the same debt as that
evidenced by, such particular Security; and, for the purposes of this
definition, any Security authenticated and delivered under Section 306 in
exchange for or in lieu of a mutilated, destroyed, lost or stolen Security shall
be deemed to evidence the same debt as the mutilated, destroyed, lost or stolen
Security.

        "Preferred Stock" of any Person means Capital Stock of such Person of
any class or classes (however designated) that ranks prior, as to the payment of
dividends or as to the distribution of assets upon any voluntary or involuntary
liquidation, dissolution or winding up of such Person, to shares of Capital
Stock of any other class of such Person.

        "Purchase Agreement" means the Purchase Agreement, dated as of January
5, 2001, by and among the Company, Salomon Smith Barney Inc. and Goldman Sachs &
Co., as such agreement may be amended from time to time.

        "Purchase Price" has the meaning set forth in the definition of
"Designated Event Offer" herein.

        "Registered Securities" means all Securities sold or otherwise disposed
of pursuant to an effective registration statement under the Securities Act,
together with their respective Successor Securities.

        "Registration Default" has the meaning set forth in Section 301 hereof.

        "Registration Rights Agreement" means the registration rights agreement
entered into by the Company for the benefit of the Purchasers, dated as of
January 12, 2000, as such agreement may be amended from time to time.

        "Regular Record Date" for the interest payable on any Interest Payment
Date means the January 1 or July 1 (whether or not a Business Day), as the case
may be, next preceding such Interest Payment Date.

        "Regulation S" means Regulation S that may be under the Securities Act
(or any successor provision), as it may be amended from time to time.

        "Regulation S Certificate" means a certificate substantially in the form
set forth in Annex A.

                                       11
<PAGE>   19

        "Regulation S Global Security" has the meaning specified in Section 201.

        "Regulation S Legend" means a legend substantially in the form of the
legend in the form of Security set forth in Section 202 that may be required to
be placed upon each Regulation S Security.

        "Regulation S Securities" means all Securities that may be required
pursuant to Section 305(c) to bear a Regulation S Legend. Such term includes the
Regulation S Global Security.

        "Restricted Global Security" has the meaning specified in Section 201.

        "Restricted Period" means the period of one (1) year beginning on and
including the later of (i) the day on which Securities are first offered to
persons other than distributors (as defined in Regulation S) in reliance on
Regulation S and (ii) the original issuance date of the Securities.

        "Restricted Securities" means all Securities required pursuant to
Section 305(c) to bear any Restricted Securities Legend. Such term includes the
Restricted Global Security.

        "Restricted Securities Certificate" means a certificate substantially in
the form set forth in Annex B.

        "Restricted Securities Legend" means, collectively, the legends
substantially in the forms of the legends required in the form of Security set
forth in Section 202 to be placed upon each Restricted Security.

        "Rule 144A" means Rule 144A under the Securities Act (or any successor
provision), as it may be amended from time to time.

        "Rule 144A Securities" means the Securities purchased by the Purchasers
from the Company pursuant to the Purchase Agreement, other than the Regulation S
Securities.

        "SEC Reports" has the meaning specified in Section 704.

        "Securities" has the meaning set forth in the recitals.

        "Securities Act" means the Securities Act of 1933 and any statute
successor thereto, in each case as amended from time to time.

        "Securities Act Legend" means a Restricted Securities Legend or a
Regulation S Legend.

                                       12
<PAGE>   20

        "Security Register" and "Security Registrar" have the respective
meanings specified in Section 305(b).

        "Senior Indebtedness" means the principal of, and interest on, rent
under, and any other amounts payable on or in or in respect of any Indebtedness
of the Company (including, without limitation, any Obligations in respect of
such Indebtedness and, in the case of Designated Senior Indebtedness, any
interest accruing after the filing of a petition by or against the Company under
any bankruptcy law, whether or not allowed as a claim after such filing in any
proceeding under such bankruptcy law), whether outstanding on the date hereof or
hereafter created, Incurred, assumed, Guaranteed or in effect Guaranteed by the
Company (including all deferrals, renewals, extensions or refundings of, or
amendments, modifications or supplements to the foregoing); provided, however,
that Senior Indebtedness does not include (v) Indebtedness evidenced by the
Securities, (w) any liability for federal, state, local or other taxes owed or
owing by the Company, (x) Indebtedness of the Company to any Subsidiary except
to the extent such Indebtedness is of a type described in clause (ii) of the
definition of Indebtedness, (y) trade payables of the Company for goods,
services or materials purchased in the ordinary course of business (other than,
to the extent they may otherwise constitute such trade payables, any obligations
of the type described in clause (viii) of the definition of Indebtedness), and
(z) any particular Indebtedness in which the instrument creating or evidencing
the same expressly provides that such Indebtedness shall not be senior in right
of payment to, or is pari passu with, or is subordinated or junior to, the
Securities.

        "Special Record Date" for the payment of any Defaulted Interest means a
date fixed by the Trustee pursuant to Section 307.

        "Stated Maturity", when used with respect to any Security, means the
date specified in such Security as the fixed date on which the principal of such
Security is due and payable.

        "Step-Down Date" has the meaning set forth in Section 301 hereof.

        "Step-Up" has the meaning set forth in Section 301 hereof.

        "Subsequent Step-Down Date" has the meaning set forth in Section 301
hereof.

        "Subsequent Step-Up" has the meaning set forth in Section 301 hereof.

        "Subsidiary" of any Person means

        (i) a corporation more than 50% of the combined voting power of the
outstanding Voting Stock of which is owned, directly or indirectly, by such
Person or by one or more other Subsidiaries of such Person or by such Person and
one or more Subsidiaries thereof or

        (ii) any other Person (other than a corporation) in which such Person,
or one or more other Subsidiaries of such Person or such Person and one or more
other Subsidiaries thereof,

                                       13
<PAGE>   21

directly or indirectly, has at least a majority ownership and power to direct
the policies, management and affairs thereof.

        "Successor Security" of any particular Security means every Security
issued after, and evidencing all or a portion of the same debt as that evidenced
by, such particular Security; and, for the purposes of this definition, any
Security authenticated and delivered under Section 306 in exchange for or in
lieu of a mutilated, destroyed, lost or stolen Security shall be deemed to
evidence the same debt as the mutilated, destroyed, lost or stolen Security.

        "Suspension Period" has the meaning specified in the Registration Rights
Agreement.

        "Termination Condition" has the meaning specified in Section 1401(a)
hereof.

        A "Termination of Trading" will be deemed to have occurred in the Class
A Common Stock (or other Capital Stock into which the Securities are then
convertible) is neither listed for trading on a United States national
securities exchange nor approved for trading on an established automated
over-the-counter trading market in the United States.

        "Trading Day" with respect to the Class A Common Stock of the Company
means (x) if such Class A Common Stock is listed or admitted for trading on the
New York Stock Exchange or another national securities exchange, a day on which
the New York Stock Exchange or such other national securities exchange is open
for business or (y) if such Class A Common Stock is quoted on the NASDAQ
National Market, a day on which trades may be made on the NASDAQ National Market
or (z) otherwise, any day other than a Saturday or Sunday or a day on which
banking institutions in the State of New York are authorized or obligated by law
or executive order to close.

        "Trust Indenture Act" means the Trust Indenture Act of 1939 as in force
at the date as of which this instrument was executed; provided, however, that in
the event the Trust Indenture Act of 1939 is amended after such date, "Trust
Indenture Act" means, to the extent required by any such amendment, the Trust
Indenture Act of 1939 as so amended.

        "Trustee" means the Person named as the "Trustee" in the first paragraph
of this instrument until a successor Trustee shall have become such pursuant to
the applicable provisions of this Indenture, and thereafter "Trustee" shall mean
such successor Trustee.

        "Unrestricted Securities Certificate" means a certificate substantially
in the form set forth in Annex C.

        "Vice President", when used with respect to the Company or the Trustee,
means any vice president, whether or not designated by a number or a word or
words added before or after the title "vice president".

                                       14
<PAGE>   22

        "Voting Stock" of any Person means Capital Stock of such Person which
ordinarily has voting power for the election of directors (or persons performing
similar functions) of such Person, whether at all times or only so long as no
senior class of securities has such voting power by reason of any contingency.

        "Waiver" has the meaning specified in Section 1201(a) hereof.

        SECTION 102. Compliance Certificates and Opinions.

        Upon any application or request by the Company to the Trustee to take
any action under any provision of this Indenture, the Company shall furnish to
the Trustee such certificates and opinions as may be required under the Trust
Indenture Act and under this Indenture. Each such certificate or opinion shall
be given in the form of an Officers' Certificate, if to be given by an officer
of the Company, or an Opinion of Counsel, if to be given by counsel, and shall
comply with the requirements of the Trust Indenture Act and any other
requirement set forth in this Indenture.

        Every certificate or opinion with respect to compliance with a condition
or covenant provided for in this Indenture shall include

                (1) a statement that each individual signing such certificate or
        opinion has read such covenant or condition and the definitions herein
        relating thereto;

                (2) a brief statement as to the nature and scope of the
        examination or investigation upon which the statements or opinions
        contained in such certificate or opinion are based;

                (3) a statement that, in the opinion of each such individual, he
        has made such examination or investigation as is necessary to enable him
        to express an informed opinion as to whether or not such covenant or
        condition has been complied with; and

                (4) a statement as to whether, in the opinion of each such
        individual, such condition or covenant has been complied with.

        SECTION 103. Form of Documents Delivered to Trustee.

        In any case where several matters are required to be certified by, or
covered by an opinion of, any specified Person, it is not necessary that all
such matters be certified by, or covered by the opinion of, only one such
Person, or that they be so certified or covered by only one document, but one
such Person may certify or give an opinion with respect to some matters and one
or more other such Persons as to other matters, and any such Person may certify
or give an opinion as to such matters in one or several documents.

        Any certificate of an officer of the Company may be based, insofar as it
relates to legal matters, upon an opinion of counsel submitted therewith, unless
such officer knows, or in the exercise of reasonable care should know, that the
opinion with respect to the matters upon which his certificate is based is
erroneous. Any opinion of counsel may be based, insofar as it relates to factual
matters, upon a certificate of an officer or officers of the Company submitted
therewith

                                       15
<PAGE>   23

stating the information on which counsel is relying, unless such counsel knows,
or in the exercise of reasonable care should know, that the certificate with
respect to such matters is erroneous.

        Where any Person is required to make, give or execute two or more
applications, requests, consents, certificates, statements, opinions or other
instruments under this Indenture, they may, but need not, be consolidated and
form one instrument.

        SECTION 104. Acts of Holders; Record Dates.

        Any request, demand, authorization, direction, notice, consent, waiver
or other action provided by this Indenture to be given or taken by Holders may
be embodied in and evidenced by one or more instruments of substantially similar
tenor signed by such Holders in person or by agent duly appointed in writing;
and, except as herein otherwise expressly provided, such action shall become
effective when such instrument or instruments are delivered to the Trustee and,
where it is hereby expressly required, to the Company. Such instrument or
instruments (and the action embodied therein and evidenced thereby) are herein
sometimes referred to as the "Act" of the Holders signing such instrument or
instruments. Proof of execution of any such instrument or of a writing
appointing any such agent shall be sufficient for any purpose of this Indenture
and (subject to Section 601) conclusive in favor of the Trustee and the Company,
if made in the manner provided in this Section.

        The fact and date of the execution by any Person of any such instrument
or writing pursuant to this Section 104 may be proved by the affidavit of a
witness of such execution or by a certificate of a notary public or other
officer authorized by law to take acknowledgments of deeds, certifying that the
individual signing such instrument or writing acknowledged to him the execution
thereof. Where such execution is by a signer acting in a capacity other than his
individual capacity, such certificate or affidavit shall also constitute
sufficient proof of his authority. The fact and date of the execution of any
such instrument or writing, or the authority of the Person executing the same,
may also be proved in any other manner which the Trustee deems sufficient.

        The ownership of Securities shall be proved by the Security Register.

        Any request, demand, authorization, direction, notice, consent, waiver
or other Act of the Holder of any Security shall bind every future Holder of the
same Security and the Holder of every Security issued upon the registration of
transfer thereof or in exchange therefor or in lieu thereof in respect of
anything done, omitted or suffered to be done by the Trustee or the Company in
reliance thereon, whether or not notation of such action is made upon such
Security.

        The Company may set any day as a record date for the purpose of
determining the Holders of Outstanding Securities entitled to give, make or take
any request, demand, authorization, direction, notice, consent, waiver or other
action provided or permitted by this Indenture to be given, made or taken by
Holders of Securities, provided that the Company may not set a record date for,
and the provisions of this paragraph shall not apply with respect to, the giving
or making of any notice, declaration, request or direction referred to in the
next paragraph. If not set by the Company prior to the first solicitation of a
Holder made by any Person in respect of any such matter referred to in the
foregoing sentence, the record date for any such matter shall

                                       16
<PAGE>   24

be the 30th day (or, if later, the date of the most recent list of Holders
required to be provided pursuant to Section 701) prior to such first
solicitation. If any record date is set pursuant to this paragraph, the Holders
of Outstanding Securities on such record date, and no other Holders, shall be
entitled to take the relevant action, whether or not such Holders remain Holders
after such record date; provided that no such action shall be effective
hereunder unless taken on or prior to the applicable expiration date by Holders
of the requisite principal amount of Outstanding Securities on such record date.
Nothing in this paragraph shall be construed to prevent the Company from setting
a new record date for any action for which a record date has previously been set
pursuant to this paragraph (whereupon the record date previously set shall
automatically and with no action by any Person be cancelled and of no effect),
and nothing in this paragraph shall be construed to render ineffective any
action taken by Holders of the requisite principal amount of Outstanding
Securities on the date such action is taken. Promptly after any record date is
set pursuant to this paragraph, the Company, at its own expense, shall cause
notice of such record date, the proposed action by Holders and the applicable
expiration date to be given to the Trustee in writing and to each Holder of
Securities in the manner set forth in Section 106.

        The Trustee may set any day as a record date for the purpose of
determining the Holders of Outstanding Securities entitled to join in the giving
or making of (i) any Notice of Default, (ii) any declaration of acceleration
referred to in Section 502, (iii) any request to institute proceedings referred
to in Section 507(2) or (iv) any direction referred to in Section 512. If any
record date is set pursuant to this paragraph, the Holders of Outstanding
Securities on such record date, and no other Holders, shall be entitled to join
in such notice, declaration, request or direction, whether or not such Holders
remain Holders after such record date; provided that no such action shall be
effective hereunder unless taken on or prior to the applicable expiration date
by Holders of the requisite principal amount of Outstanding Securities on such
record date. Nothing in this paragraph shall be construed to prevent the Trustee
from setting a new record date for any action for which a record date has
previously been set pursuant to this paragraph (whereupon the record date
previously set shall automatically and with no action by any Person be cancelled
and of no effect), and nothing in this paragraph shall be construed to render
ineffective any action taken by Holders of the requisite principal amount of
Outstanding Securities on the date such action is taken. Promptly after any
record date is set pursuant to this paragraph, the Trustee, at the Company's
expense, shall cause notice of such record date, the proposed action by Holders
and the applicable expiration date to be given to the Company in writing and to
each Holder of Securities in the manner set forth in Section 106.

        With respect to any record date set pursuant to this Section, the party
hereto which sets such record dates may designate any day as the "expiration
date" and from time to time may change the expiration date to any earlier or
later day; provided that no such change shall be effective unless notice of the
proposed new expiration date is given to the other party hereto in writing, and
to each Holder of Securities in the manner set forth in Section 106, on or prior
to the existing expiration date. If an expiration date is not designated with
respect to any record date set pursuant to this Section, the party hereto which
set such record date shall be deemed to have initially designated the 180th day
after such record date as the expiration date with respect thereto, subject to
its right to change the expiration date as provided in this paragraph.
Notwithstanding the foregoing, no expiration date shall be later than the 180th
day after the applicable record date.

                                       17
<PAGE>   25

        Without limiting the foregoing, a Holder entitled hereunder to take any
action hereunder with regard to any particular Security may do so with regard to
all or any part of the principal amount of such Security or by one or more duly
appointed agents each of which may do so pursuant to such appointment with
regard to all or any part of such principal amount.

        SECTION 105. Notices, Etc., to Trustee and Company.

        Any request, demand, authorization, direction, notice, consent, waiver
or Act of Holders or other document provided or permitted by this Indenture to
be made upon, given or furnished to, or filed with,

                (1) the Trustee by any Holder or by the Company shall be
        sufficient for every purpose hereunder if delivered in writing to the
        Trustee at its Corporate Trust Office, Attention: Corporate Trust
        Administration, or

                (2) the Company by the Trustee or by any Holder shall be
        sufficient for every purpose hereunder (unless otherwise herein
        expressly provided) if in writing and mailed, first-class postage
        prepaid, to the Company addressed to the Company at the address of its
        principal office specified in the first paragraph of this instrument or
        at any other address previously furnished in writing to the Trustee by
        the Company.

        SECTION 106. Notice to Holders; Waiver.

        Where this Indenture provides for notice to Holders of any event, such
notice shall be sufficiently given (unless otherwise herein expressly provided)
if (i) in the case of a Global Security, in writing by facsimile and/or by
overnight mail to the Depositary, and (ii) in the case of securities other than
Global Securities, in writing and mailed, first-class postage prepaid, to each
Holder affected by such event, at his address as it appears in the Security
Register, not later than the latest date (if any), and not earlier than the
earliest date (if any), prescribed for the giving of such notice. In any case
where notice to Holders is given by mail, neither the failure to mail such
notice, nor any defect in any notice so mailed, to any particular Holder shall
affect the sufficiency of such notice with respect to other Holders. Where this
Indenture provides for notice in any manner, such notice may be waived in
writing by the Person entitled to receive such notice, either before or after
the event, and such waiver shall be the equivalent of such notice. Waivers of
notice by Holders shall be filed with the Trustee, but such filing shall not be
a condition precedent to the validity of any action taken in reliance upon such
waiver.

        In case by reason of the suspension of regular mail service or by reason
of any other cause it shall be impracticable to give such notice by mail, then
such notification as shall be made with the approval of the Trustee shall
constitute a sufficient notification for every purpose hereunder.

        SECTION 107.  Application of Trust Indenture Act.

        The Trust Indenture Act shall apply as a matter of contract to this
Indenture for purposes of interpretation, construction and defining the rights
and obligations hereunder. If any provision hereof limits, qualifies or
conflicts with a provision of the Trust Indenture Act that is required under
such Act to be a part of and govern this Indenture, the latter provision shall
control. If any

                                       18
<PAGE>   26

provision of this Indenture modifies or excludes any provision of the Trust
Indenture Act that may be so modified or excluded, the latter provision shall be
deemed to apply to this Indenture as so modified or to be excluded, as the case
may be.

        SECTION 108. Effect of Headings and Table of Contents.

        The Article and Section headings herein and the Table of Contents are
for convenience only and shall not affect the construction hereof.

        SECTION 109. Successors and Assigns.

        All covenants and agreements in this Indenture by the Company shall bind
its successors and assigns, whether so expressed or not.

        SECTION 110. Separability Clause.

        In case any provision in this Indenture or in the Securities shall be
invalid, illegal or unenforceable, the validity, legality and enforceability of
the remaining provisions shall not in any way be affected or impaired thereby.

        SECTION 111. Benefits of Indenture.

        Nothing in this Indenture or in the Securities, express or implied,
shall give to any Person, other than the parties hereto and their successors
hereunder, the Holders of Securities and, as to Article Fifteen hereof, the
holders of Senior Indebtedness, any benefit or any legal or equitable right,
remedy or claim under this Indenture.

        SECTION 112. Governing Law.

        This Indenture and the Securities shall be governed by and construed in
accordance with the laws of the State of New York.

        SECTION 113. Legal Holidays.

        In any case where any Interest Payment Date, Designated Event Payment
Date or Stated Maturity of any Security shall not be a Business Day, then
(notwithstanding any other provision of this Indenture or of the Securities)
payment of interest or principal (and premium, if any) need not be made on such
date, but may be made on the next succeeding Business Day with the same force
and effect as if made on the Interest Payment Date, Designated Event Payment
Date or at the Stated Maturity, provided that no interest shall accrue for the
period from and after such Interest Payment Date, Designated Event Payment Date
or Stated Maturity, as the case may be.

                                       19
<PAGE>   27

                                  ARTICLE TWO.

                                SECURITIES FORMS

        SECTION 201. Forms Generally.

        The Securities and the Trustee's certificates of authentication thereof
shall be in substantially the forms set forth in this Article, with such
appropriate legends, insertions, omissions, substitutions and other variations
as are required or permitted by this Indenture, and may have such letters,
numbers or other marks of identification and such legends or endorsements placed
thereon as may be required to comply with the rules of any securities exchange
or as may, consistently herewith, be determined by the officers executing such
Securities, as evidenced by their execution of the Securities.

        Upon their original issuance, Rule 144A Securities shall be issued in
the form of one or more Global Securities registered in the name of the
Depositary or its nominee and deposited with the Trustee, as custodian for the
Depositary, for credit by the Depositary to the respective accounts of
beneficial owners of the Securities represented thereby (or such other accounts
as they may direct). Such Global Securities, together with their Successor
Securities which are Global Securities other than the Regulation S Global
Security, are collectively herein called the "Restricted Global Security". Upon
their original issuance, Regulation S Securities shall be issued in the form of
one or more Global Securities registered in the name of the Depositary, or its
nominee and deposited with the Trustee, as custodian for the Depositary, for
credit to the respective accounts of the beneficial owners of the Securities
represented thereby (or such other accounts as they may direct), provided that
upon such deposit all such Securities shall be credited to or through accounts
maintained at the Depositary by or on behalf of Euroclear or Cedel. Such Global
Securities, together with their Successor Securities which are Global Securities
other than the Restricted Global Security, are collectively herein called the
"Regulation S Global Security".

        The definitive Securities shall be printed, lithographed or engraved or
produced by any combination of these methods on steel engraved borders or may be
produced in any other manner, all as determined by the officers executing such
Securities, as evidenced by their execution of such Securities.

        In certain cases described elsewhere herein, the legends set forth in
Section 202 may be omitted from Securities issued hereunder.

        SECTION 202.  Form of Face of Security.

        [If Restricted Securities, then insert -- THIS NOTE HAS NOT BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT").
THE HOLDER HEREOF, BY PURCHASING THIS NOTE, AGREES FOR THE BENEFIT OF THE
COMPANY THAT THIS NOTE MAY NOT BE RESOLD, PLEDGED OR OTHERWISE TRANSFERRED (X)
PRIOR TO THE SECOND ANNIVERSARY OF THE ISSUANCE HEREOF (OR ANY PREDECESSOR
SECURITY HERETO) OR (Y) BY ANY HOLDER THAT WAS AN AFFILIATE OF THE COMPANY AT
ANY TIME DURING THE THREE MONTHS PRECEDING THE DATE

                                       20
<PAGE>   28

OF SUCH TRANSFER, IN EITHER CASE, OTHER THAN (1) TO THE COMPANY, (2) SO LONG AS
THIS NOTE IS ELIGIBLE FOR RESALE PURSUANT TO RULE 144A UNDER THE SECURITIES ACT
("RULE 144A"), TO A PERSON WHOM THE SELLER REASONABLY BELIEVES IS A QUALIFIED
INSTITUTIONAL BUYER WITHIN THE MEANING OF RULE 144A, PURCHASING FOR ITS OWN
ACCOUNT OR FOR THE ACCOUNT OF A QUALIFIED INSTITUTIONAL BUYER TO WHOM NOTICE IS
GIVEN THAT RESALE, PLEDGE OR OTHER TRANSFER IS BEING MADE IN RELIANCE ON RULE
144A, (3) IN AN OFFSHORE TRANSACTION IN ACCORDANCE WITH REGULATION S UNDER THE
SECURITIES ACT, (4) PURSUANT TO AN EXEMPTION FROM REGISTRATION UNDER THE
SECURITIES ACT PROVIDED BY RULE 144 (IF APPLICABLE) UNDER THE SECURITIES ACT, OR
(5) PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT, IN
EACH CASE IN ACCORDANCE WITH ANY APPLICABLE SECURITIES LAWS OF ANY STATE OF THE
UNITED STATES. THE HOLDER HEREOF, BY PURCHASING THIS NOTE REPRESENTS AND AGREES
FOR THE BENEFIT OF THE COMPANY THAT IT IS (1) A QUALIFIED INSTITUTIONAL BUYER
WITHIN THE MEANING OF RULE 144A OR (2) A NON-U.S. PERSON OUTSIDE THE UNITED
STATES WITHIN THE MEANING OF (OR AN ACCOUNT SATISFYING THE REQUIREMENTS OF
PARAGRAPH (O)(2) OF RULE 902 UNDER) REGULATION S UNDER THE SECURITIES ACT.]

        [If a Regulation S Security (if required), then insert -- THIS SECURITY
HAS NOT BEEN REGISTERED UNDER THE U.S. SECURITIES ACT OF 1933 (THE "SECURITIES
ACT") AND MAY NOT BE OFFERED, SOLD OR DELIVERED IN THE UNITED STATES OR TO, OR
FOR THE ACCOUNT OR BENEFIT OF, ANY U.S. PERSON, UNLESS THIS SECURITY IS
REGISTERED UNDER THE SECURITIES ACT OR AN EXEMPTION FROM THE REGISTRATION
REQUIREMENTS THEREOF IS AVAILABLE.]

        [If the Security is a Global Security, insert the legends required by
Section 204 of the Indenture]

                                       21
<PAGE>   29

                             XO COMMUNICATIONS, INC.

                 5 3/4% Convertible Subordinated Notes Due 2009

                                                             CUSIP No. 983764AAG

No. ____________      $__________

        XO Communications, Inc., a Delaware corporation (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., or registered assigns, the principal sum of _________ Dollars [if this
Security is a Global Security, then insert: (which principal amount may from
time to time be increased or decreased to such other principal amounts) (which,
taken together with the principal amounts of all other Outstanding Securities,
shall not exceed $517,500,000 in the aggregate at any time, by adjustments made
on the records of the Trustee hereinafter referred to in accordance with the
Indenture)] on January 15, 2009, and to pay interest thereon, in cash in arrears
semiannually on January 15 and July 15 in each year, with payment commencing on
July 15, 2001, and interest accruing from January 12, 2001, or from the most
recent Interest Payment Date to which interest has been paid or duly provided
for, at the rate of 5 3/4% per annum, until the principal hereof is paid or made
available for payment, provided, however, that if (i) the Company's registration
statement (the "Registration Statement") under the Securities Act of 1933, as
amended (the "Securities Act") registering this Security for resale has not
become or been declared effective by July 11, 2001, or (ii) the Registration
Statement is declared effective, but shall thereafter cease to be effective
(otherwise than during any permitted Suspension Period described in the
Registration Rights Agreement) without being succeeded promptly by an additional
registration statement filed and declared effective, in each case upon the terms
and conditions set forth in the Registration Rights Agreement (each such event
referred to in clauses (i) and (ii), but excluding any permitted Suspension
Period described in the Registration Rights Agreement, a "Registration
Default"), then interest will accrue (in addition to the stated rate of interest
on the Securities) (the "Step-Up") at a rate of 0.25% per annum, determined
daily, on the principal amount of the Securities, for the period from the
occurrence of the Registration Default until such time (the "Step-Down Date") as
no Registration Default is in effect and the per annum rate of such interest
shall increase (the "Subsequent Step-Up") by an additional 0.25% per annum for
each subsequent 90-day period during which a Registration Default continues
(provided that the Step-Up and all Subsequent Step-Up interest rates shall not
exceed 0.5% per annum in the aggregate) and Liquidated Damages will be payable
at such increased rate until such time (the "Subsequent Step Down Date") as such
Registration Default is no longer in effect (after which such interest rate will
be restored to its initial rate). Interest accruing as a result of the Step-Up
or the Subsequent Step-Up (which shall be computed on the basis of a 365-day
year for the actual number of days elapsed) is referred to herein as "Liquidated
Damages." Accrued Liquidated Damages, if any, shall be paid simultaneously with
the payment of accrued ainterest at the stated rate of interest set forth above.
References herein to "interest" shall be deemed to include, without duplication,
Liquidated Damages, unless the context otherwise requires.

        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

                                       22
<PAGE>   30

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 January 1
or July 1 (whether or not a Business Day), as the case may be, next preceding
such Interest Payment Date. 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 such defaulted interest, and (to the extent lawful) interest on
such defaulted interest at the rate borne by the Securities, 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 not less than 10 days prior to
such Special Record Date, or may be paid at any time in any other lawful manner
not inconsistent with the requirements of any securities exchange on which the
Securities may be listed, and upon such notice as may be required by such
exchange, all as more fully provided in said Indenture. If this Security is
issued in the form of a Global Security, payments of the principal of (and
premium, if any) and interest on this Security shall be made in immediately
available funds to the Depositary. If this Security is issued in certificated
form, payment of the principal of (and premium, if any) and interest on this
Security will be made at the corporate trust office of the Trustee and at the
office or agency of the Company maintained for that purpose in the Borough of
Manhattan, The City of New York, or at such other office or agency maintained by
the Company for such purpose, in such coin or currency of the United States of
America as at the time of payment is legal tender for payment of public and
private debts; provided, however, that payment of interest may be made at the
option of the Company by check mailed to the address of the Person entitled
thereto as such address shall appear in the Security Register.

        Reference is hereby made to the further provisions of this Security set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

        Unless the certificate of authentication hereon has been duly 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.

<TABLE>
<S>                                      <C>                               <C>
Dated:  January 12, 2001                 XO Communications, Inc.

                                         By:

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

        -----------------
        Name:
        Title:
</TABLE>

                                       23
<PAGE>   31

        SECTION 203. Form of Reverse of Security.

        This Security is one of a duly authorized issue of Securities of the
Company designated as its 5 3/4% Convertible Subordinated Notes Due 2009 (the
"Securities"), issued under an indenture dated as of January 12, 2001 (herein
called the "Indenture"), between the Company and U.S. Trust Company, National
Association, as trustee (herein called the "Trustee", which term includes any
successor trustee under the Indenture). The Securities are limited in the
aggregate principal amount to $517,500,000. Reference is hereby made to the
Indenture and all indentures supplemental thereto 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.

Redemption

        This security is not redeemable prior to maturity.

Repurchase at the Option of Holders upon a Designated Event

        Upon the occurrence of a Change of Control, or, following the
termination of the Credit Agreement or if the lenders thereunder have waived
certain restrictions with respect to the incurrence of indebtedness under
Section 6.1 thereof as such restrictions relate to the incurrence of the
Indebtedness evidenced by the Securities (a "Waiver"), a Termination of Trading,
the Holder of this Security may require the Company, subject to certain
limitations provided in the Indenture, to repurchase all or a specified portion
of the Securities at a purchase price in cash in an amount equal to 100% of the
principal amount thereof, plus accrued and unpaid interest (if any) to the
Designated Event Payment Date (subject to the right of Holders of record on the
relevant record date to receive interest due on the relevant interest payment
date). At the option of the Company, the purchase price (and accrued and unpaid
interest) may be paid in cash or, subject to the conditions provided in the
Indenture, by delivery of shares of Class A Common Stock of the Company having a
fair market value equal to the purchase price (and accrued and unpaid interest).
For purposes of this paragraph, the fair market value of shares of Class A
Common Stock of the Company shall be determined by the Company and shall be
equal to 95% of the average of the Current Market Price for the five consecutive
Trading Days immediately preceding and including and ending on the third Trading
Day prior to the Designated Event Payment Date. References herein to "principal"
shall be deemed to include, without duplication, the purchase price payable in
connection with a Designated Event Offer, unless the context otherwise requires.

        If the Designated Event is a Change of Control, holders of the
Securities will not have the foregoing put right if: (i) the daily market price
per share of the Class A Common Stock for any five Trading Days within the
period of 10 consecutive Trading Days ending immediately after the later of the
Change of Control or the public announcement thereof or, if the Change of
Control results in the reclassification, conversion or exchange of outstanding
shares of Class A Common Stock, the period of 10 consecutive Trading Days ending
immediately before the Change of Control, shall equal or exceed 105% of the
Conversion Price of the Securities in effect

                                       24
<PAGE>   32

on the date of the Change of Control or the public announcement thereof, as
applicable, or (ii) at least 90% of the consideration received by holders of
Class A Common Stock (or such other Capital Stock into which the Securities are
then convertible) in the Change of Control transaction consists of shares of
Capital Stock traded on a U.S. national securities exchange or quoted on the
NASDAQ National Market, and as a result of the transaction, this Security
becomes convertible into such consideration.

Conversion Rights

        Subject to and upon compliance with the provisions of the Indenture, the
Holder of this Security is entitled, at his or her option, at any time following
the original issue date of the Securities and on or before the close of business
on the Business Day immediately preceding January 15, 2009, or in case the
Company has terminated the conversion rights of the Holder hereof or the Holder
hereof has exercised his right to require the Company to repurchase this
Security or such portion hereof, then in respect of this Security until but
(unless the Company defaults in making the payment due upon repurchase) not
after, the close of business on the Conversion Termination Date or the Business
Day immediately preceding the Designated Event Payment Date, as the case may be,
to convert this Security (or any portion of the principal amount hereof that is
an integral multiple of $1,000, provided that the unconverted portion of such
principal amount is $1,000 or any integral multiple of $1,000 in excess thereof)
into fully paid and nonassessable shares of Class A Common Stock of the Company
at an initial Conversion Rate of 39.1484 shares of Class A Common Stock of the
Company for each $1,000 principal amount of Security (or at the current adjusted
Conversion Rate if an adjustment has been made as provided in the Indenture) by
surrender of this Security, duly endorsed or assigned to the Company or in blank
and, in case such surrender shall be made during the period from the close of
business on any Regular Record Date next preceding any Interest Payment Date to
the opening of business on such Interest Payment Date, also accompanied by
payment in New York Clearing House or other funds acceptable to the Company of
an amount equal to the interest payable on such Interest Payment Date on the
principal amount of this Security then being converted, and also the conversion
notice hereon duly executed, to the Company at the Corporate Trust Office of the
Trustee, or at such other office or agency of the Company, subject to any laws
or regulations applicable thereto and subject to the right of the Company to
terminate the appointment of any Conversion Agent (as defined below) as may be
designated by it for such purpose in the Borough of Manhattan, The City of New
York, or at such other offices or agencies as the Company may designate (each a
"Conversion Agent"). Subject, in the case of a conversion after the close of
business on the Regular Record Date next preceding any Interest Payment Date and
on or before the close of business on such Interest Payment Date, to the right
of the Holder of this Security (or any Predecessor Security of record as of such
Regular Record Date) to receive the related installment of interest to the
extent and under the circumstances provided in the Indenture, no cash payment or
adjustment is to be made on conversion for interest accrued hereon from the
Interest Payment Date next preceding the day of conversion, or for dividends on
the Class A Common Stock of the Company issued on conversion hereof. The Company
shall thereafter deliver to the Holder the fixed number of shares of Class A
Common Stock of the Company (together with any cash adjustment, as provided in
the Indenture) into which this Security is convertible and such delivery will be
deemed to satisfy the Company's obligation to pay the principal amount of this
Security. No fractions of shares or scrip representing fractions of shares will
be issued on conversion, but instead of any fractional

                                       25
<PAGE>   33

interest the Company shall pay a cash adjustment as provided in the Indenture;
provided, however, that the Company reserves the right at its option to issue
whole shares in payment of any fractions of shares. The Conversion Rate is
subject to adjustment as provided in the Indenture. In addition, the Indenture
provides that in case of certain consolidations or mergers to which the Company
is a party (other than a consolidation or merger that does not result in any
reclassification, conversion, exchange or cancellation of the Class A Common
Stock of the Company) or the conveyance, transfer, sale or lease of all or
substantially all of the property and assets of the Company, the Indenture shall
be amended, without the consent of any Holders of Securities, so that this
Security, if then Outstanding, will be convertible thereafter, during the period
this Security shall be convertible as specified above, only into the kind and
amount of securities, cash and other property receivable upon such
consolidation, merger, conveyance, transfer, sale or lease by a holder of the
number of shares of Class A Common Stock of the Company into which this Security
could have been converted immediately prior to such consolidation, merger,
conveyance, transfer, sale or lease. No adjustment in the Conversion Rate will
be made until such adjustment would require an increase or decrease of at least
one percent of such price, provided that any adjustment that would otherwise be
made will be carried forward and taken into account in the computation of any
subsequent adjustment. Shares of Class A Common Stock, issued upon conversion of
this Security shall bear the legend required by Section 305(d) of the Indenture.

Optional Termination of Conversion Rights

        On or after January 18, 2003, the Company may, at its option, terminate
the conversion rights of this Security, in whole or in part, if the Current
Market Price of Class A Common Stock of the Company equals or exceeds 150% (on
or prior to January 18, 2004) or 135% (thereafter) of the prevailing Conversion
Price then in effect for at least 20 Trading Days within any period of 30
consecutive Trading Days (a "Measurement Period"), including the last day of
such period.

        To exercise its option to terminate the conversion rights of holders of
Securities, the Company must issue a press release for publication on the Dow
Jones News Service (or a comparable news service) (the date of such notice being
the "Notice Date") announcing the conversion termination date selected by it
(the "Conversion Termination Date") prior to the opening of business on the
second trading day after any applicable Measurement Period. The Conversion
Termination Date shall in no event be prior to January 18, 2003 and shall be on
the date that is not less than 30 days after the Notice Date nor more than 60
days after the Notice Date. The press release shall announce the Conversion
Termination Date and provide the current Conversion Price of the Securities and
the Current Market Price of the Class A Common Stock, in each case as of the
close of business on the last day of the applicable Measurement Period. The
Company will also give notice containing the same information by first class
mail to the holders of the Securities not more than four Business Days after it
issues the press release. Conversion rights will terminate at the close of
business on the Conversion Termination Date.

        If the Conversion Termination Date occurs on or before January 18, 2004,
the Company will make an additional payment in cash (herein called the
"Make-Whole Payment") with respect to the Securities converted into Class A
Common Stock of the Company after the Notice Date. The Make-Whole Payment will
be equal to the present value of the aggregate value of the interest payments
that would have been payable on this Security after the date of conversion on

                                       26
<PAGE>   34

each semi-annual interest payment date from the Conversion Termination Date
through January 15, 2004. The present value will be calculated using the bond
equivalent yield on U.S. Treasury notes or bills having a term nearest in length
to that of the relevant period as of the day immediately preceding the
Conversion Termination Date.

        The term "Current Market Price" of Class A Common Stock for any day
means the last reported per share sale price, regular way on such day, or, if no
sale takes place on such day, the average of the reported closing per share bid
and asked prices on such day, regular way, in either case as reported on the
NASDAQ National Market or, if the Class A Common Stock is not quoted or admitted
to trading on such quotation system, on the principal national securities
exchange or quotation system on which the Class A Common Stock may be listed or
admitted to trading or quoted, or, if not listed or admitted to trading or
quoted on any national securities exchange or quotation system, the average of
the closing per share bid and asked prices of the Class A Common Stock on the
over-the-counter market on the day in question as reported by the National
Quotation Bureau Incorporated, or similar generally accepted reporting service,
or, if not so available in such manner, as furnished by any NASDAQ member firm
selected from time to time by the Company's board of directors for that purpose,
or, if not so available in such manner, as otherwise determined in good faith by
our board of directors.

Subordination

        The indebtedness evidenced by this Security is, to the extent and in the
manner provided in the Indenture, subordinate and subject in right of payment to
the prior payment in full in cash of all Senior Indebtedness of the Company, and
this Security is issued subject to such 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 effectuate the
subordination so provided and (c) appoints the Trustee his attorney-in-fact for
any and all such purposes.

Events of Default

        If an Event of Default shall occur and be continuing, the principal
amount of all the Securities may be declared due and payable in the manner and
with the effect provided in the Indenture.

No Sinking Fund

        The Securities do not have the benefit of any sinking fund obligations.

Defeasance

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

                                       27
<PAGE>   35

Modification; Amendment and Waiver

        Unless the context otherwise requires, the Securities shall constitute
one series for all purposes under the Indenture, including without limitation,
amendments, waivers, and Designated Event Offers.

        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, the Holders of not
less than 25% in principal amount of the Outstanding Securities 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 principal
amount of Outstanding Securities 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 or principal hereof or any premium or interest hereon on or after the
respective due dates expressed herein.

        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 under the Indenture at any time by the
Company and the Trustee with the consent of the Holders of a majority in
aggregate principal amount of the Securities at the time Outstanding. The
Indenture also contains provisions permitting the Holders of specified
percentages in aggregate principal amount of the Securities at the time
Outstanding, on behalf of the Holders of all the Securities, to waive compliance
by the Company with certain provisions of the Indenture and certain past
defaults under the Indenture and their consequences. Without the consent of any
Holder of Securities, the Company and the Trustee may amend or modify the
Indenture for certain purposes specified therein. Any such consent or waiver by
or on behalf of 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.

Miscellaneous

        [If not a Global Security -- In the event of purchase pursuant to a
Designated Event Offer of this Security in part only, a new Security or
Securities of like tenor for the unredeemed or unpurchased portion hereof will
be issued in the name of the Holder hereof upon the cancellation hereof.]

        [If a Global Security insert -- In the event of a deposit or withdrawal
of an interest in this Security (including upon an exchange, transfer or
repurchase of this Security in part only) effected in accordance with the
Applicable Procedures, the Security Registrar, upon receipt of notice of such
event from the Depositary's custodian for this Security, shall make an
adjustment on its records to reflect an increase or decrease of the Outstanding
principal amount of this Security resulting from such deposit or withdrawal, as
the case may be.]

                                       28
<PAGE>   36

        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 premium, if any) and
interest on this Security at the times, place and rate, and in the coin or
currency, herein prescribed.

        As provided in the Indenture and subject to certain limitations therein
set forth, the transfer of this Security is registerable in the Security
Register, upon surrender of this Security for registration of transfer at the
office or agency of the Company in the Borough of Manhattan, The City of New
York, 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 his attorney duly authorized in writing, and thereupon one
or more new Securities, of authorized denominations and like tenor and for the
same aggregate principal amount, will be issued to the designated transferee or
transferees.

        The Securities are issuable only in registered form without coupons in
denominations of $1,000 principal amount and any integral multiple thereof. As
provided in the Indenture and subject to certain limitations therein set forth,
Securities are exchangeable for a like tenor and aggregate principal amount of
Securities 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 of the Securities, but the Company may require payment of a sum
sufficient to cover any transfer tax or other similar governmental charge
payable in connection therewith.

        Interest (other than Liquidated Damages) on this Security shall be
computed on the basis of a 360-day year of twelve 30-day months.

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

        Prior to the time of due presentment of this Security for registration
of transfer, the Company, the Trustee and any agent of the Company or the
Trustee may treat the Person in whose name this Security is registered as the
owner hereof for all purposes, whether or not this Security be overdue, and
neither the Company, the Trustee nor any agent shall be affected by notice to
the contrary.

        THIS SECURITY SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE
LAW OF THE STATE OF NEW YORK BUT WITHOUT GIVING EFFECT TO APPLICABLE PRINCIPLES
OF CONFLICTS OF LAW TO THE EXTENT THAT THE APPLICATION OF THE LAWS OF ANOTHER
JURISDICTION WOULD BE REQUIRED THEREBY.

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

                                       29
<PAGE>   37

                 Form of Trustee's Certificate of Authentication

        The Trustee's certificate of authentication shall be in substantially
the following form:

                     TRUSTEE'S CERTIFICATE OF AUTHENTICATION

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

        This is one of the Securities referred to in the within-mentioned

        Indenture.

                      U.S. TRUST COMPANY, NATIONAL ASSOCIATION, as Trustee

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

                             Authorized Signatory

                                       30
<PAGE>   38

                                CONVERSION NOTICE

        The undersigned Holder of this Security hereby irrevocably exercises the
option to convert this Security, or any portion of the principal amount hereof
(which is $1,000 or an integral multiple of $1,000 in excess thereof, provided
that the unconverted portion of such principal amount is $1,000 or any integral
multiple of $1,000 in excess thereof) below designated, into shares of Class A
Common Stock of the Company in accordance with the terms of the Indenture
referred to in this Security, and directs that such shares, together with any
check in payment for any fractional share and any Securities representing any
unconverted principal amount hereof, be delivered to and be registered in the
name of the undersigned unless a different name has been indicated below. If
shares of Class A Common Stock of the Company or Securities are to be registered
in the name of a Person other than the undersigned, (a) the undersigned will pay
all transfer taxes payable with respect thereto and (b) signature(s) must be
guaranteed by an Eligible Guarantor Institution with membership in an approved
signature guarantee program pursuant to Rule 17Ad-15 under the Securities
Exchange Act of 1934. Any amount required to be paid by the undersigned on
account of interest accompanies this Security.

Dated:
      ---------

                                  Signature(s)

If shares or Securities are to be registered in the name of a Person other than
the Holder, please print such Person's name and address:

Name

Address

Social Security or other Identification

Number, if any

Signature Guarantee:
                     - --------------------------------------------------------
                      Notice: Signature(s) must be guaranteed by an "eligible
                      guarantor institution" meeting the requirements of the
                      Trustee, which requirements will include membership or
                      participation in STAMP or such other "signature guarantee
                      program" as may be determined by the Trustee in

                                       31
<PAGE>   39

                      addition to, or in substitution for STAMP, all in
                      accordance with the Securities Exchange Act of 1934, as
                      amended.

If only a portion of the Securities is to be converted, please indicate:

1.      Principal amount to be converted:

        $

2.      Principal amount and denomination of Securities representing unconverted
        principal amount to be issued:

        Amount $

        ($1,000 or any integral multiple of $1,000 in excess thereof, provided
that the unconverted portion of such principal amount is $1,000 or any integral
multiple of $1,000 in excess thereof)

                                       32
<PAGE>   40

                                 Assignment Form

        If you, the Holder, want to assign this Security, fill in the form below
and have your signature guaranteed:

I or we assign and transfer this Security to:

                           ----------------------------------
        (Insert assignee's social security or tax ID number)
                                                            -----------------
             (Print or type assignee's name, address and zip code)

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

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

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

and irrevocably appoint _________________________________________________ of
__________________________________________________________________ agent to
transfer this Security on the books of the Company. The agent may substitute
another to act for such agent.

<TABLE>
<S>                    <C>
Dated:                  Your signature:
        ---------                      --------------------------------------
                                      (Sign exactly as your name appears on the
                                       other side of this Security)

                                      By:
                                        ---------------------------------------
                                       NOTICE: To be executed by an executive
                                       officer

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

</TABLE>

                                       33
<PAGE>   41

                       OPTION OF HOLDER TO ELECT PURCHASE

        If you wish to have this Security purchased by the Company pursuant to
Section 1201 of the Indenture, check the box: [_]

        If you wish to have a portion of this Security purchased by the Company
pursuant to Section 1201 of the Indenture, state the amount:

        $               .
         ---------------

        In the event that the Purchase Price shall be paid in shares of Class A
Common Stock of the Company, provide the name in which the certificate(s) for
shares of Class A Common Stock of the Company are to be issued, together with
the address of such person:

If shares or Securities are to be registered in the name of a Person other than
the Holder, please print such Person's name and address:

(Print or type name, address and zip code)

Name

Address

<TABLE>
<S>                     <C>             <C>
Dated:                  Your signature:
        -----------                     ----------------------------------------
                                        of this Security)(Sign exactly as your
                                        name appears on the other side
</TABLE>

                      [TO BE ATTACHED TO GLOBAL SECURITIES]

                                       34
<PAGE>   42

              SCHEDULE OF INCREASES OR DECREASES IN GLOBAL SECURITY

The initial principal amount of this Global Security is $[              ].

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

<TABLE>
<S>             <C>                     <C>                      <C>
Date of         Amount of decrease in   Amount of increase in    Principal Amount of
Transfer        Principal Amount of     Principal Amount of      Global Security with
                this Global Security    this Global Security     such increase or
                                                                 decrease
</TABLE>

        SECTION 204. Additional Provisions Required in Global Security.

        Any Global Security issued hereunder shall, in addition to the
provisions contained in Sections 202 and 203, bear a legend in substantially the
following form:

        [If a Global Security, insert -- THIS 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 SECURITY MAY NOT BE
EXCHANGED IN WHOLE OR IN PART FOR A SECURITY REGISTERED, AND NO TRANSFER OF THIS
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.]

        [If a Global Security to be held by The Depository Trust Company, insert
-- UNLESS THIS SECURITY IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE ISSUER OR ITS
AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT, AND ANY SECURITY
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 A PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE
& CO., HAS AN INTEREST HEREIN.]

                                       35
<PAGE>   43

        SECTION 205. Form of Trustee's Certificate of Authentication.

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

                        U.S. Trust Company, National Association,
                        as Trustee

                        By
                            -----------------------------

                                Authorized Signatory

                                 ARTICLE THREE.

                                 THE SECURITIES

        SECTION 301. Title and Terms.

        The aggregate principal amount of Securities which may be authenticated
and delivered under this Indenture is limited to $517,500,000, except for
Securities authenticated and delivered upon registration of transfer of, or in
exchange for, or in lieu of, other Securities pursuant to Section 304, 305, 306
or 906 or in connection with a Designated Event Offer pursuant to Section 1201.

        The Securities shall be known and designated as the "5 3/4% Convertible
Subordinated Notes due 2009" of the Company. The Stated Maturity of the
Securities shall be January 15, 2009. The Securities shall bear interest at the
rate of 5 3/4% per annum, from January 12, 2001 or from the most recent Interest
Payment Date thereafter to which interest has been paid or duly provided for, as
the case may be, payable semi-annually on January 15 and July 15, commencing
July 15, 2001, until the principal thereof is paid or made available for
payment; provided, however, if (i) the Company's registration statement (the
"Registration Statement") under the Securities Act of 1933, as amended (the
"Securities Act") registering this Security for resale has not become or been
declared effective by July 11, 2001, or (ii) the Registration Statement is
declared effective, but shall thereafter cease to be effective (otherwise than
during any permitted Suspension Period described in the Registration Rights
Agreement) without being succeeded promptly by an additional registration
statement filed and declared effective, in each case upon the terms and
conditions set forth in the Registration Rights Agreement (each such event
referred to in clauses (i) and (ii), but excluding any permitted Suspension
Period described in the Registration Rights Agreement, a "Registration
Default"), then interest will accrue (in addition to the stated rate of
interest on the Securities) (the "Step-Up") at a rate of 0.25% per annum,
determined daily, on the principal amount of the Securities, for the period
from the occurrence of the Registration Default until such time (the "Step-Down
Date") as no Registration Default is in effect and the per annum rate of such
interest shall increase (the "Subsequent Step-Up") by an additional 0.25% per
annum for each subsequent 90-day period during which a Registration Default
continues (provided that the Step-Up and all Subsequent Step-Up interest rates
shall not exceed 0.5% per annum in the aggregate) and Liquidated Damages will
be payable at such increased rate until such time (the "Subsequent Step Down
Date") as such Registration Default is

                                       36
<PAGE>   44

no longer in effect (after which such interest rate will be restored to its
initial rate). Interest accruing as a result of the Step-Up or the Subsequent
Step-Up (which shall be computed on the basis of a 365-day year for the actual
number of days elapsed). In connection with the cash payment of any Liquidated
Damages, the Company shall notify the Trustee (the "Liquidated Damages Notice")
on or before the later to occur of (i) the Regular Record Date preceding such
payment of any Liquidated Damages, and (ii) the date on which any such
Liquidated Damages begins to accrue, of the amount of Liquidated Damages to be
paid by the Company on the next Interest Payment Date or other date on which
interest, including Liquidated Damages, is payable. In the event of the
occurrence of a Step-Down Date during the period between the date on which the
Liquidated Damages Notice is given and the next Interest Payment Date, the
Company shall so notify the Trustee and shall provide the Trustee with the
revised amount of Liquidated Damages to be paid by the Company on such Interest
Payment Date.

        In the case of a default in payment of principal and premium, if any,
upon acceleration or repurchase, interest shall be payable pursuant to the
preceding paragraph on such overdue principal (and premium, if any), such
interest shall be payable on demand and, if not so paid on demand, such interest
shall itself bear interest at the rate of 53/4% per annum (to the extent that
the payment of such interest shall be legally enforceable), and shall accrue
from the date of such demand for payment to the date payment of such interest
has been made or duly provided for, and such interest on unpaid interest shall
also be payable on demand.

        If this Security is issued in the form of a Global Security, payments of
the principal of (and premium, if any) and interest on this Security shall be
made in immediately available funds to the Depositary. If the Securities are
issued in certificated form, the principal of and premium, if any, and interest
on the Securities shall be payable at the corporate trust office of the Trustee
in the Borough of Manhattan, The City of New York, New York, maintained for such
purpose and at any other office or agency maintained by the Company for such
purpose; provided, however, that at the option of the Company payment of
interest may be made by check mailed to the address of the Person entitled
thereto as such address shall appear in the Security Register.

        The Securities shall be subject to repurchase by the Company pursuant to
a Designated Event Offer as provided in Section 1201.

        The Securities shall not have the benefit of any sinking fund
obligations.

        The Securities shall be subject to defeasance and covenant defeasance at
the option of the Company as provided in Article Eleven.

        Unless the context otherwise requires, the Securities shall constitute
one series for all purposes under the Indenture, including without limitation,
amendments, waiver and Designated Event Offers.

        SECTION 302. Denominations.

        The Securities shall be issuable only in registered form without coupons
and only in denominations of $1,000 and any integral multiple thereof.

                                       37
<PAGE>   45

        SECTION 303. Execution, Authentication, Delivery and Dating.

        The Securities shall be executed on behalf of the Company by its Chief
Executive Officer, its President, its Executive Vice President or one of its
Vice Presidents and attested by its Secretary or Assistant Secretary. The
signature of any of these officers on the Securities may be manual or facsimile.

        Securities bearing the manual or facsimile signatures of individuals who
were at any time the proper officers of the Company shall bind the Company,
notwithstanding that such individuals or any of them have ceased to hold such
offices prior to the authentication and delivery of such Securities or did not
hold such offices at the date of such Securities.

        At any time and from time to time after the execution and delivery of
this Indenture, the Company may deliver Securities executed by the Company to
the Trustee for authentication, together with a Company Order for the
authentication and delivery of such Securities; and the Trustee in accordance
with such Company Order shall authenticate and deliver such Securities as in
this Indenture provided and not otherwise.

        Each Security shall be dated the date of its authentication.

        No Security shall be entitled to any benefit under this Indenture or be
valid or obligatory for any purpose unless there appears on such Security a
certificate of authentication substantially in the form provided for herein
executed by the Trustee by manual signature, and such certificate upon any
Security shall be conclusive evidence, and the only evidence, that such Security
has been duly authenticated and delivered hereunder.

        SECTION 304. Temporary Securities.

        Pending the preparation of definitive Securities, the Company may
execute, and upon a Company Order the Trustee shall authenticate and deliver,
temporary Securities which are printed, lithographed, typewritten, mimeographed
or otherwise produced, in any authorized denomination, substantially of the
tenor of the definitive Securities in lieu of which they are issued and with
such appropriate insertions, omissions, substitutions and other variations as
the officers executing such Securities may determine, as evidenced by their
execution of such Securities.

        If temporary Securities are issued, the Company will cause definitive
Securities to be prepared without unreasonable delay. After the preparation of
definitive Securities, the temporary Securities shall be exchangeable for
definitive Securities upon surrender of the temporary Securities at any office
or agency of the Company designated pursuant to Section 1002, without charge to
the Holder. Upon surrender for cancellation of any one or more temporary
Securities, the Company shall execute and the Trustee shall authenticate and
deliver in exchange therefor a like tenor and principal amount of definitive
Securities of authorized denominations. Until so exchanged, the temporary
Securities shall in all respects be entitled to the same benefits under this
Indenture as definitive Securities.

                                       38
<PAGE>   46

        SECTION 305. Registration, Registration of Transfer, Exchange and
Conversion.

        (a) The Company shall cause to be kept at the Corporate Trust Office of
the Trustee a register (the register maintained in such office and in any other
office or agency designated pursuant to Section 1002 being herein sometimes
collectively referred to as the "Security Register") in which, subject to such
reasonable regulations as they may prescribe, the Company shall provide for the
registration of Securities and of transfers, exchanges and conversions of
Securities. The Trustee is hereby appointed "Security Registrar" for the purpose
of registering Securities and transfers, exchanges and conversions of Securities
as herein provided.

        Subject to the other provisions of this Indenture regarding restrictions
on transfer, upon surrender for registration of transfer of any Security at an
office or agency of the Company designated pursuant to Section 1002 for such
purpose in accordance with the terms hereof, the Company shall execute, and the
Trustee shall authenticate and deliver, in the name of the designated transferee
or transferees, one or more new Securities of any authorized denominations and
of a like tenor and aggregate principal amount and bearing such restrictive
legends as may be required by this Indenture.

        At the option of the Holder and subject to the other provisions of this
Section 305, Securities may be exchanged for other Securities of any authorized
denominations and of a like tenor and aggregate principal amount, upon surrender
of the Securities to be exchanged at such office or agency. Whenever any
Securities are so surrendered for exchange, the Company shall execute, and the
Trustee shall authenticate and deliver, the Securities which the Holder making
the exchange is entitled to receive.

        Subject to the other provisions of this Indenture, upon surrender for
partial conversion of any Security at an office or agency of the Company
designated pursuant to Section 1002 for such purpose in accordance with the
terms hereof, the Company shall execute, and the Trustee shall authenticate and
deliver, in the name of the Holder, one or more new Securities of any authorized
denominations and of a like tenor and in an aggregate principal amount equal to
the unconverted portion of such Security and bearing such restrictive legends as
may be required by this Indenture.

        All Securities issued upon any registration of transfer or exchange or
partial conversion of Securities shall be the valid obligations of the Company,
evidencing the same debt, and (subject to the provisions in the Securities
regarding the payment of Liquidated Damages) entitled to the same benefits under
this Indenture, as the Securities surrendered upon such registration of transfer
or exchange.

        Every Security presented or surrendered for registration of transfer or
for exchange or conversion shall (if so required by the Company or the Trustee)
be duly endorsed, or be accompanied by a written instrument of transfer in form
satisfactory to the Company and the Security Registrar duly executed, by the
Holder thereof or his attorney duly authorized in writing.

        No service charge shall be made to the Holder for any registration of
transfer or exchange or conversion of Securities, but the Company may require
payment of a sum sufficient to cover any tax or other governmental charge that
may be imposed in connection with any registration of

                                       39
<PAGE>   47

transfer or exchange or conversion of Securities, other than exchanges pursuant
to Section 304, 305 or 906, in accordance with any Designated Event Offer
pursuant to Section 1201 not involving any transfer or in connection with any
conversion not involving any transfer.

        (b) Certain Transfers and Exchanges. Notwithstanding any other provision
of this Indenture or the Securities, transfers and exchanges of Securities and
beneficial interests in a Global Security of the kinds specified in this Section
305(b) shall be made only in accordance with this Section 305(b).

               (i) Restricted Global Security to Regulation S Global Security.
        If the owner of a beneficial interest in the Restricted Global Security
        wishes at any time to transfer such interest to a Person who wishes to
        acquire the same in the form of a beneficial interest in the Regulation
        S Global Security, such transfer may be effected only in accordance with
        the provisions of this Clause (b)(i) and Clause (b)(iv) below and
        subject to the Applicable Procedures. Upon receipt by the Trustee, as
        Security Registrar, of (A) an order given by the Depositary or its
        authorized representative directing that a beneficial interest in the
        Regulation S Global Security in a specified principal amount be credited
        to a specified Agent Member's account and that a beneficial interest in
        the Restricted Global Security in an equal principal amount be debited
        from another specified Agent Member's account and (B) a Regulation S
        Certificate, satisfactory to the Trustee and duly executed by the owner
        of such beneficial interest in the Restricted Global Security or his
        attorney duly authorized in writing, then the Trustee, as Security
        Registrar but subject to Clause (b)(vii) below, shall reduce the
        principal amount of the Restricted Global Security and increase the
        principal amount of the Regulation S Global Security by such specified
        principal amount.

               (ii) Regulation S Global Security to Restricted Global Security.
        If the owner of a beneficial interest in the Regulation S Global
        Security wishes at any time to transfer such interest to a Person who
        wishes to acquire the same in the form of a beneficial interest in the
        Restricted Global Security, such transfer may be effected only in
        accordance with this Clause (b)(ii) and subject to the Applicable
        Procedures. Upon receipt by the Trustee, as Security Registrar, of (A)
        an order given by the Depositary or its authorized representative
        directing that a beneficial interest in the Restricted Global Security
        in a specified principal amount be credited to a specified Agent
        Member's account and that a beneficial interest in the Regulation S
        Global Security in an equal principal amount be debited from another
        specified Agent Member's account and (B) if such transfer is to occur
        during the Restricted Period, a Restricted Securities Certificate,
        satisfactory to the Trustee and duly executed by the owner of such
        beneficial interest in the Regulation S Global Security or his attorney
        duly authorized in writing, then the Trustee, as Security Registrar,
        shall reduce the principal amount of the Regulation S Global Security
        and increase the principal amount of the Restricted Global Security by
        such specified principal amount.

               (iii) Non-Global Security to Non-Global Security. A Security that
        is not a Global Security may be transferred, in whole or in part, to a
        Person who takes delivery in the form of another Security that is not a
        Global Security as provided in Section 305(a), provided that, if the
        Security to be transferred in whole or in part is a Restricted Security,
        or is a Regulation S Security and the transfer is to occur during the
        Restricted Period,

                                       40
<PAGE>   48

        then the Trustee shall have received (A) a Restricted Securities
        Certificate, satisfactory to the Trustee and duly executed by the
        transferor Holder or his attorney duly authorized in writing, in which
        case the transferee Holder shall take delivery in the form of a
        Restricted Security, or (B) a Regulation S Certificate, satisfactory to
        the Trustee and duly executed by the transferor Holder or his attorney
        duly authorized in writing, in which case the transferee Holder shall
        take delivery in the form of a Regulation S Security (subject in every
        case to Section 305(c)).

               (iv) Regulation S Global Security to be Held Through Euroclear or
        Cedel during Restricted Period. The Company shall use its best efforts
        to cause the Depositary to ensure that, until the expiration of the
        Restricted Period, beneficial interests in the Regulation S Global
        Security may be held only in or through accounts maintained at the
        Depositary by Euroclear or Cedel (or by Agent Members acting for the
        account thereof), and no person shall be entitled to effect any transfer
        or exchange that would result in any such interest being held otherwise
        than in or through such an account; provided that this Clause (b)(iv)
        shall not prohibit any transfer or exchange of such an interest in
        accordance with Clause (b)(ii) above.

               (v) Exchanges of Book-Entry Securities for Certificated
        Securities. A beneficial interest in a Global Security may not be
        exchanged for a Security in certificated form unless (i) DTC (x)
        notifies the Company that it is unwilling or unable to continue as
        Depositary for the Global Security or (y) has ceased to be a clearing
        agency registered under the Exchange Act and in either case the Company
        thereupon fails to appoint a successor Depositary, (ii) the Company, at
        its option, notifies the Trustee in writing that it elects to cause the
        issuance of the Securities in certificated form or (iii) there shall
        have occurred and be continuing an Event of Default or any event which
        after notice or lapse of time or both would be an Event of Default with
        respect to the Securities. In all cases, certificated Securities
        delivered in exchange for any Global Security or beneficial interests
        therein will be registered in the names, and issued in any approved
        denominations, requested by or on behalf of the Depositary (in
        accordance with its customary procedures). Any certificated Security
        issued in exchange for an interest in a Global Security will bear the
        legend restricting transfers that is borne by such Global Security. Any
        such exchange will be effected through the DWAC System and an
        appropriate adjustment will be made in the records of the Security
        Registrar to reflect a decrease in the principal amount of the relevant
        Global Security.

        (c) Securities Act Legends. Rule 144A Securities and their Successor
Securities shall bear a Restricted Securities Legend, and the Regulation S
Securities and their Successor Securities shall bear a Regulation S Legend,
subject to the following:

               (i) subject to the following Clauses of this Section 305(c), a
        Security or any portion thereof which is exchanged, upon transfer or
        otherwise, for a Global Security or any portion thereof shall bear the
        Securities Act Legend borne by such Global Security while represented
        thereby;

               (ii) subject to the following Clauses of this Section 305(c), a
        new Security which is not a Global Security and is issued in exchange
        for another Security (including a

                                       41
<PAGE>   49

        Global Security) or any portion thereof, upon transfer or otherwise,
        shall bear the Securities Act Legend borne by such other Security,
        provided that, if such new Security is required pursuant to Section
        305(b)(v) or (vi) to be issued in the form of a Restricted Security, it
        shall bear a Restricted Securities Legend and, if such new Security is
        so required to be issued in the form of a Regulation S Security, it
        shall bear a Regulation S Legend;

                (iii) Registered Securities shall not bear a Securities Act
        Legend;

               (iv) at any time after the Securities may be freely transferred
        without registration under the Securities Act or without being subject
        to transfer restrictions pursuant to the Securities Act, a new Security
        which does not bear a Securities Act Legend may be issued in exchange
        for or in lieu of a Security (other than a Global Security) or any
        portion thereof which bears such a legend if the Trustee has received an
        Unrestricted Securities Certificate, satisfactory to the Trustee and
        duly executed by the Holder of such legended Security or his attorney
        duly authorized in writing, and after such date and receipt of such
        certificate, the Trustee shall authenticate and deliver such a new
        Security in exchange for or in lieu of such other Security as provided
        in this Article Three;

               (v) a new Security which does not bear a Securities Act Legend
        may be issued in exchange for or in lieu of a Security (other than a
        Global Security) or any portion thereof which bears such a legend if, in
        the Company's judgment, placing such a legend upon such new Security is
        not necessary to ensure compliance with the registration requirements of
        the Securities Act, and the Trustee, at the direction of the Company,
        shall authenticate and deliver such a new Security as provided in this
        Article Three; and

               (vi) notwithstanding the foregoing provisions of this Section
        305(c), a Successor Security of a Security that does not bear a
        particular form of Securities Act Legend shall not bear such form of
        legend unless the Company has reasonable cause to believe that such
        Successor Security is a "restricted security" within the meaning of Rule
        144, in which case the Trustee, at the direction of the Company, shall
        authenticate and deliver a new Security bearing a Restricted Securities
        Legend in exchange for such Successor Security as provided in this
        Article Three.

        (d) Until two years after the original issuance date of any Security,
any stock certificate representing Class A Common Stock issued upon conversion
of such Security shall bear a legend in substantially the following form, unless
such Class A Common Stock has been transferred pursuant to a registration
statement that has been declared effective under the Securities Act (and which
continues to be effective at the time of such transfer) or such Class A Common
Stock has been issued upon conversion of Securities that have been transferred
pursuant to a registration statement that has been declared effective under the
Securities Act, or unless otherwise agreed by the Company in writing with
written notice thereof to the transfer agent:

        THE CLASS A COMMON STOCK EVIDENCED HEREBY HAS NOT BEEN REGISTERED UNDER
THE U.S. SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), OR ANY STATE
SECURITIES LAWS, AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD, EXCEPT AS SET
FORTH BELOW.

                                       42
<PAGE>   50

        THE HOLDER HEREOF AGREES THAT PRIOR TO THE DATE THAT IS TWO YEARS AFTER
THE LATER OF THE ORIGINAL ISSUANCE OF THE SECURITY UPON THE CONVERSION OF WHICH
THE CLASS A COMMON STOCK EVIDENCED HEREBY WAS ISSUED AND THE LAST DATE ON WHICH
XO COMMUNICATIONS, INC. (THE "COMPANY") OR ANY "AFFILIATE" (AS DEFINED IN RULE
144 UNDER THE SECURITIES ACT) OF THE COMPANY WAS THE OWNER OF THE SECURITY OR
THE CLASS A COMMON STOCK EVIDENCED HEREBY (THE "RESTRICTION TERMINATION DATE"):
(1) IT WILL NOT RESELL OR OTHERWISE TRANSFER THE CLASS A COMMON STOCK EVIDENCED
HEREBY EXCEPT (A) TO THE COMPANY OR ANY SUBSIDIARY THEREOF, (B) TO AN
INSTITUTIONAL "ACCREDITED INVESTOR" (AS DEFINED IN RULE 501(a)(1), (2), (3) OR
(7) UNDER THE SECURITIES ACT) THAT, PRIOR TO SUCH TRANSFER, FURNISHES TO THE
BANK OF NEW YORK, AS TRANSFER AGENT (OR A SUCCESSOR TRANSFER AGENT, AS
APPLICABLE), A SIGNED LETTER CONTAINING CERTAIN REPRESENTATIONS AND AGREEMENTS
RELATING TO THE RESTRICTIONS ON TRANSFER OF THE CLASS A COMMON STOCK EVIDENCED
HEREBY (THE FORM OF WHICH LETTER CAN BE OBTAINED FROM SUCH TRANSFER AGENT OR A
SUCCESSOR TRANSFER AGENT, AS APPLICABLE), (C) PURSUANT TO ANOTHER AVAILABLE
EXEMPTION FROM REGISTRATION PROVIDED UNDER THE SECURITIES ACT (IF AVAILABLE), OR
(D) PURSUANT TO A REGISTRATION STATEMENT WHICH HAS BEEN DECLARED EFFECTIVE UNDER
THE SECURITIES ACT (AND WHICH CONTINUES TO BE EFFECTIVE AT THE TIME OF SUCH
TRANSFER); (2) PRIOR TO SUCH TRANSFER BEFORE THE RESTRICTION TERMINATION DATE,
OTHER THAN A TRANSFER PURSUANT TO CLAUSE 1(D) ABOVE, IT WILL FURNISH U.S. TRUST
COMPANY, NATIONAL ASSOCIATION, AS TRANSFER AGENT (OR A SUCCESSOR TRANSFER AGENT,
AS APPLICABLE), SUCH CERTIFICATIONS, LEGAL OPINIONS OR OTHER INFORMATION AS IT
MAY REASONABLY REQUIRE TO CONFIRM THAT SUCH TRANSFER IS BEING MADE PURSUANT TO
AN EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE REGISTRATION
REQUIREMENTS OF THE SECURITIES ACT; AND (3) IT WILL DELIVER TO EACH PERSON TO
WHOM THE CLASS A COMMON STOCK EVIDENCED HEREBY IS TRANSFERRED (OTHER THAN A
TRANSFER PURSUANT TO CLAUSE 1(E) ABOVE) A NOTICE SUBSTANTIALLY TO THE EFFECT OF
THIS LEGEND.

        THIS LEGEND WILL BE REMOVED UPON THE EARLIER OF THE TRANSFER OF THE
CLASS A COMMON STOCK EVIDENCED HEREBY PURSUANT TO CLAUSE 1(E) ABOVE OR UPON THE
RESTRICTION TERMINATION DATE.

Any such Class A Common Stock as to which such restrictions on transfer shall
have expired in accordance with their terms or as to which the conditions for
removal of the foregoing legend set forth therein have been satisfied may, upon
surrender of the certificates representing such shares of Class A Common Stock
for exchange in accordance with the procedures of the transfer agent for the
Class A Common Stock, be exchanged for a new certificate or certificates for a
like number of shares of Class A Common Stock, which shall not bear the
restrictive legend required by this Section 206.

                                       43
<PAGE>   51

        SECTION 306. Mutilated, Destroyed, Lost and Stolen Securities.

        If any mutilated Security is surrendered to the Trustee, the Company
shall execute and the Trustee shall authenticate and deliver in exchange
therefor a new Security of like tenor and principal amount and bearing a number
not contemporaneously outstanding.

        If there shall be delivered to the Company and the Trustee (i) evidence
to their satisfaction of the destruction, loss or theft of any Security and (ii)
such security or indemnity as may be required by them to save each of them and
any agent of either of them harmless, then, in the absence of notice to the
Company or the Trustee that such Security has been acquired by a bona fide
purchaser, the Company shall execute and the Trustee shall authenticate and
deliver, in lieu of any such destroyed, lost or stolen Security, a new Security
of like tenor and principal amount and bearing a number not contemporaneously
outstanding.

        In case any such mutilated, destroyed, lost or stolen Security has
become or is about to become due and payable, the Company in the discretion of
the Company may, instead of issuing a new Security, pay such Security.

        Upon the issuance of any new Security under this Section, the Company
may require the payment of a sum sufficient to cover any tax or other
governmental charge that may be imposed in relation thereto and any other
expenses (including the fees and expenses of the Trustee) connected therewith.

        Every new Security issued pursuant to this Section in lieu of any
destroyed, lost or stolen Security shall constitute an original additional
contractual obligation of the Company, whether or not the destroyed, lost or
stolen Security shall be at any time enforceable by anyone, and shall be
entitled to all the benefits of this Indenture equally and proportionately with
any and all other Securities duly issued hereunder.

        The provisions of this Section are exclusive and shall preclude (to the
extent lawful) all other rights and remedies with respect to the replacement or
payment of mutilated, destroyed, lost or stolen Securities.

        SECTION 307. Payment of Interest; Interest Rights Preserved.

        Interest on any Security which is payable, and is punctually paid or
duly provided for, on any Interest Payment Date shall be paid to the Person in
whose name that Security (or one or more Predecessor Securities) is registered
at the close of business on the Regular Record Date for such interest.

        Any interest (including Liquidated Damages) on any Security which is
payable, but is not punctually paid or duly provided for, on any Interest
Payment Date (herein called "Defaulted Interest") shall (a) bear interest at the
rate per annum stated in the form of Security included herein (to the extent
that the payment of such interest shall be legally enforceable), and (b)
forthwith cease to be payable to the Holder on the relevant Regular Record Date
by virtue of having been such Holder, and such Defaulted Interest may be paid by
the Company, at its election in each case, as provided in Clause (1) or (2)
below:

                                       44
<PAGE>   52

                (1) The Company may elect to make payment of any Defaulted
        Interest to the Persons in whose names the Securities (or their
        respective Predecessor Securities) are registered at the close of
        business on a Special Record Date for the payment of such Defaulted
        Interest, which shall be fixed in the following manner. The Company
        shall notify the Trustee in writing of the amount of Defaulted Interest
        proposed to be paid on each Security and the date of the proposed
        payment, and at the same time the Company shall deposit with the Trustee
        an amount of money equal to the aggregate amount proposed to be paid in
        respect of such Defaulted Interest or shall make arrangements
        satisfactory to the Trustee for such deposit prior to the date of the
        proposed payment, such money when deposited to be held in trust for the
        benefit of the Persons entitled to such Defaulted Interest as in this
        Clause provided. Thereupon the Trustee shall fix a Special Record Date
        for the payment of such Defaulted Interest which shall be not more than
        15 days and not less than 10 days prior to the date of the proposed
        payment and not less than 10 days after the receipt by the Trustee of
        the notice of the proposed payment. The Trustee shall promptly notify
        the Company of such Special Record Date and, in the name and at the
        expense of the Company, shall cause notice of the proposed payment of
        such Defaulted Interest and the Special Record Date therefor to be
        mailed, first-class postage prepaid, to each Holder at his address as it
        appears in the Security Register, not less than 10 days prior to such
        Special Record Date. Notice of the proposed payment of such Defaulted
        Interest and the Special Record Date therefor having been so mailed,
        such Defaulted Interest shall be paid to the Persons in whose names the
        Securities (or their respective Predecessor Securities) are registered
        at the close of business on such Special Record Date and shall no longer
        be payable pursuant to the following Clause (2).

                (2) The Company may make payment of any Defaulted Interest in
        any other lawful manner not inconsistent with the requirements of any
        securities exchange on which the Securities may be listed, and upon such
        notice as may be required by such exchange, if, after notice given by
        the Company to the Trustee of the proposed payment pursuant to this
        Clause, such manner of payment shall be deemed practicable by the
        Trustee.

        Subject to the foregoing provisions of this Section, each Security
delivered under this Indenture upon registration of transfer of or in exchange
for or in lieu of any other Security shall carry the rights to interest accrued
and unpaid, and to accrue, which were carried by such other Security.

        SECTION 308. Persons Deemed Owners.

        Prior to due presentment of a Security for registration of transfer, the
Company, the Trustee and any agent of the Company or the Trustee may treat the
Person in whose name such Security is registered as the owner of such Security
for the purpose of receiving payment of principal of and premium, if any, and
(subject to Section 307) interest on such Security and for all other purposes
whatsoever, whether or not such Security be overdue, and none of the Company,
the Trustee or any agent of the Company or the Trustee shall be affected by
notice to the contrary.

                                       45
<PAGE>   53

        SECTION 309. Cancellation.

        All Securities surrendered for payment, registration of transfer,
exchange, pursuant to any Designated Event Offer pursuant to Section 1301 or for
conversion shall, if surrendered to any Person other than the Trustee, be
delivered to the Trustee and shall be promptly cancelled by it. The Company may
at any time deliver to the Trustee for cancellation any Securities previously
authenticated and delivered hereunder which the Company may have acquired in any
manner whatsoever, and all Securities so delivered shall be promptly cancelled
by the Trustee. No Securities shall be authenticated in lieu of or in exchange
for any Securities cancelled as provided in this Section, except as expressly
permitted by this Indenture. All cancelled Securities held by the Trustee shall
be disposed of in accordance with its standard procedures or as directed by a
Company Order; provided, however, that the Trustee shall not be required to
destroy such Securities.

        SECTION 310. Computation of Interest.

        Interest on the Securities shall be computed on the basis of a 360-day
year of twelve 30-day months, except that Liquidated Damages shall be computed
on the basis of a 365-day year.

        SECTION 311. CUSIP and ISIN Numbers.

        The Company in issuing Securities may use "CUSIP" and "ISIN" numbers (if
then generally in use) in addition to serial numbers; if so, the Trustee shall
use such "CUSIP" and "ISIN" numbers in addition to serial numbers in Designated
Event Offers as a convenience to Holders; provided that any such notice may
state that no representation is made as to the correctness of such CUSIP and
ISIN numbers either as printed on the Securities or as contained in any
Designated Event Offer and that reliance may be placed only on the serial or
other identification numbers printed on the Securities, and any such repurchase
shall not be affected by any defect in or omission of such CUSIP and ISIN
numbers.

                                  ARTICLE FOUR.

                           SATISFACTION AND DISCHARGE

        SECTION 401. Satisfaction and Discharge of Indenture.

        This Indenture shall cease to be of further effect as to all outstanding
Securities (except as to (i) rights of registration of transfer and exchange and
conversion, (ii) substitution of apparently mutilated, defaced, destroyed, lost
or stolen Securities, (iii) rights of holders of Securities to receive payment
of principal of and premium, if any, and interest on the Securities, (iv)
rights, obligations and immunities of the Trustee under the Indenture and (v)
rights of the holders of the Securities as beneficiaries of the Indenture with
respect to any property deposited with the Trustee payable to all or any of
them), and the Trustee, on demand of and at the expense of the Company, shall
execute proper instruments acknowledging satisfaction and discharge of this
Indenture, when

                                       46
<PAGE>   54

                (1) either

                        (A) the Company will have paid or caused to be paid the
                principal of and premium, if any, and interest on the Securities
                as and when the same will have become due and payable; or

                        (B) all outstanding Securities (except lost, stolen or
                destroyed Securities which have been replaced or paid) have been
                delivered to the Trustee for cancellation;

        and the Company, in the case of (A) above, has deposited or caused to be
        deposited with the Trustee as trust funds in trust for the purpose an
        amount sufficient to pay and discharge the entire indebtedness on such
        Securities not theretofore delivered to the Trustee for cancellation,
        for principal of and premium, if any, and interest to the date of such
        deposit (in the case of Securities which have become due and payable) or
        to the Stated Maturity;

                (2) the Company has paid or caused to be paid all other sums
        payable hereunder by the Company;

                (3) the Company has delivered to the Trustee an Officers'
        Certificate and an Opinion of Counsel, each stating that all conditions
        precedent herein provided for relating to the satisfaction and discharge
        of this Indenture have been complied with; and

                (4) the Trustee shall have received such other documents and
        assurances as the Trustee shall have reasonably requested.

Notwithstanding the satisfaction and discharge of this Indenture, (i) the
obligations of the Company to the Trustee under Section 607, (ii) substitution
of apparently mutilated, defaced, destroyed, lost or stolen Securities, (iii)
rights of holders of Securities to receive payment of principal of and premium,
if any, and interest on the Securities or to convert the Securities, (iv)
rights, obligations and immunities of the Trustee under this Indenture
(including, if money shall have been deposited with the Trustee pursuant to
subclause (B) of Clause (1) of this Section, the obligations of the Trustee
under Section 402 and the last paragraph of Section 1003), and (v) rights of
holders of the Securities as beneficiaries of this Indenture with respect to any
property deposited with the Trustee payable to all or any of them, shall
survive.

        SECTION 402. Application of Trust Money.

        Subject to the provisions of the last paragraph of Section 1003, all
money deposited with the Trustee pursuant to Section 401 shall be held in trust
and applied by it, in accordance with the provisions of the Securities and this
Indenture, to the payment, either directly or through any Paying Agent
(including the Company acting as its own Paying Agent) as the Trustee may
determine, to the Persons entitled thereto, of the principal (and premium, if
any) and interest for whose payment such money has been deposited with the
Trustee.

                                       47
<PAGE>   55

                                 ARTICLE FIVE.

                                    REMEDIES

        SECTION 501. Events of Default.

        "Event of Default", wherever used herein, means any one of the following
events (whatever the reason for such Event of Default and whether it shall be
voluntary or involuntary or be effected by operation of law or pursuant to any
judgment, decree or order of any court or any order, rule or regulation of any
administrative or governmental body) or caused by Article Fifteen:

                (1) default in the payment of the principal of any Security when
        due, whether or not such payment is prohibited by the subordination
        provisions of this Indenture; or

                (2) continuance of the default in the payment of any interest
        upon any Security for a period of 30 days after the date on which such
        interest becomes due and payable, whether or not such payment is
        prohibited by the subordination provisions of this Indenture; or

                (3) default in the payment of principal and interest upon any
        Security required to be purchased pursuant to a Designated Event Offer
        pursuant to Section 1201 when due and payable, whether or not such
        payment is prohibited by the subordination provisions hereof; or

                (4) failure by the Company to provide timely notice of a
        Designated Event; or

                (5) default in the performance, or breach, of any covenant or
        warranty of the Company in this Indenture or in any Security (other than
        a covenant or warranty a default in whose performance or whose breach is
        elsewhere in this Section specifically dealt with), and continuance of
        such default or breach for a period of 60 days after there has been
        given, by registered or certified mail, to the Company by the Trustee or
        to the Company and the Trustee by the Holders of at least 25% in
        aggregate principal amount of the Outstanding Securities a written
        notice specifying such default or breach and requiring it to be remedied
        and stating that such notice is a "Notice of Default" hereunder; or

                (6) a default or defaults under any bond(s), debenture(s),
        note(s) or other evidence(s) of Indebtedness by the Company or any
        Material Subsidiary of the Company or under any mortgage(s),
        indenture(s) or instrument(s) under which there may be issued or by
        which there may be secured or evidenced any Indebtedness of such type by
        the Company or any such Material Subsidiary with a principal amount then
        outstanding, individually or in the aggregate, in excess of $10 million,
        whether such Indebtedness now exists or shall hereafter be created,
        which default or defaults shall constitute a failure to pay such
        Indebtedness when due at the final maturity thereof, or shall have
        resulted in such Indebtedness becoming or being declared due and payable
        prior to the date on which it would otherwise have become due and
        payable; or

                                       48
<PAGE>   56

                (7) a final judgment or final judgments (not subject to appeal)
        for the payment of money are entered against the Company or any Material
        Subsidiary in an aggregate amount in excess of $10 million by a court or
        courts of competent jurisdiction, which judgments remain undischarged or
        unstayed for a period (during which execution shall not be effectively
        stayed) of 45 days after the right to appeal all such judgments has
        expired; or

                (8) the entry by a court having jurisdiction in the premises of
        (A) a decree or order for relief in respect of the Company or any
        Material Subsidiary in an involuntary case or proceeding under any
        applicable Federal or State bankruptcy, insolvency, reorganization or
        other similar law or (B) a decree or order adjudging the Company or any
        Material Subsidiary a bankrupt or insolvent, or approving as properly
        filed a petition seeking reorganization, arrangement, adjustment or
        composition of or in respect of the Company or any Material Subsidiary
        under any applicable Federal or State law, or appointing a custodian,
        receiver, liquidator, assignee, trustee, sequestrator or other similar
        official of the Company or any Material Subsidiary or of any substantial
        part of its property, or ordering the winding up or liquidation of its
        affairs, and the continuance of any such decree or order for relief or
        any such other decree or order unstayed and in effect for a period of 60
        consecutive days; or

                (9) the commencement by the Company or any Material Subsidiary
        of a voluntary case or proceeding under any applicable Federal or State
        bankruptcy, insolvency, reorganization or other similar law or of any
        other case or proceeding to be adjudicated a bankrupt or insolvent, or
        the consent by it to the entry of a decree or order for relief in
        respect of the Company or any Material Subsidiary in an involuntary case
        or proceeding under any applicable Federal or State bankruptcy,
        insolvency, reorganization or other similar law or to the commencement
        of any bankruptcy or insolvency case or proceeding against it, or the
        filing by it of a petition or answer or consent seeking reorganization
        or relief under any applicable Federal or State law, or the consent by
        it to the filing of such petition or to the appointment of or taking
        possession by a custodian, receiver, liquidator, assignee, trustee,
        sequestrator or other similar official of the Company or any Material
        Subsidiary or of any substantial part of its property, or the making by
        it of an assignment for the benefit of creditors, or the admission by it
        in writing of its inability to pay its debts generally as they become
        due, or the taking of corporate action by the Company or any Material
        Subsidiary in furtherance of any such action.

        SECTION 502. Acceleration of Maturity; Rescission and Annulment.

        Subject to Article Fifteen hereof, if an Event of Default (other than an
Event of Default specified in Section 501(10) or (11) with respect to the
Company) occurs and is continuing, then and in every such case the Trustee or
the Holders of not less than 25% in aggregate principal amount of the
Outstanding Securities may declare the principal of all the Securities to be due
and payable immediately, by a notice in writing to the Company (and to the
Trustee if given by Holders), and upon any such declaration such principal and
any accrued interest, together with all other amounts due under this Indenture,
shall become immediately due and payable. If an Event of Default specified in
Section 501(10) or (11) with respect to the Company occurs, the

                                       49
<PAGE>   57

principal of and any accrued interest on the Securities then Outstanding,
together with all other amounts due under this Indenture, shall ipso facto
become immediately due and payable without any declaration or other Act on the
part of the Trustee or any Holder; provided that the provisions of Article
Fifteen hereof shall have been complied with.

        At any time after such a declaration of acceleration has been made and
before a judgment or decree for payment of the money due based on acceleration
has been obtained by the Trustee as hereinafter in this Article provided, the
Holders of a majority in aggregate principal amount of the Outstanding
Securities, by written notice to the Company and the Trustee, may rescind and
annul such declaration and its consequences if:

                (1) the Company has paid or deposited with the Trustee a sum
        sufficient to pay

                        (A) all overdue interest (including any Liquidated
                Damages) on all Securities,

                        (B) the principal of (and premium, if any, on) any
                Securities which have become due otherwise than by such
                declaration of acceleration (including any Securities required
                to have been purchased on the Designated Event Payment Date
                pursuant to a Designated Event Offer made by the Company) and
                interest thereon at the rate borne by the Securities,

                        (C) to the extent that payment of such interest is
                lawful, interest upon overdue interest at the applicable rate
                borne by the Securities, and

                        (D) all sums paid or advanced by the Trustee hereunder
                and the reasonable compensation, expenses, disbursements and
                advances of the Trustee, its agents and counsel;

        and

                        (2) all Events of Default, other than the non-payment of
        the principal of Securities which have become due solely by such
        declaration of acceleration, have been cured or waived as provided in
        Section 513.

No such rescission shall affect any subsequent default or impair any right
consequent thereon.

        SECTION 503. Collection of Indebtedness and Suits for Enforcement by
Trustee.

        The Company covenants that if

                (1) default is made in the payment of any interest on any
        Security (including any Liquidated Damages) when such interest becomes
        due and payable and such default continues for a period of 30 days, or

                (2) default is made in the payment of the principal of (or
        premium, if any, on) any Security at the Maturity thereof,

                                       50
<PAGE>   58

the Company will, upon demand of the Trustee, pay to it, for the benefit of the
Holders of such Securities, the whole amount then due and payable on such
Securities for principal (and premium, if any) and interest, and, to the extent
that payment of such interest shall be legally enforceable, interest on any
overdue principal (and premium, if any) and on any overdue interest, at the rate
provided by the Securities, and, in addition thereto, such further amount as
shall be sufficient to cover the costs and expenses incurred by the Trustee
under this Indenture, including the reasonable compensation, expenses,
disbursements and advances of the Trustee, its agents and counsel.

        If the Company fails to pay such amounts forthwith upon such demand, the
Trustee, in its own name and as trustee of an express trust, may institute a
judicial proceeding for the collection of the sums so due and unpaid, may
prosecute such proceeding to judgment or final decree, and may enforce the same
against the Company or any other obligor upon the Securities and collect the
moneys adjudged or decreed to be payable in the manner provided by law out of
the property of the Company or any other obligor upon the Securities, wherever
situated.

        If an Event of Default occurs and is continuing, the Trustee may in its
discretion proceed to protect and enforce its rights and the rights of the
Holders by such appropriate judicial proceedings as the Trustee shall deem most
effective to protect and enforce any such rights, whether for the specific
enforcement of any covenant or agreement in this Indenture or in aid of the
exercise of any power granted herein, or to enforce any other proper remedy.

        SECTION 504. Trustee May File Proofs of Claim.

        In case of any judicial proceeding relative to the Company (or any other
obligor upon the Securities), its property or its creditors, the Trustee shall
be entitled and empowered, by intervention in such proceeding or otherwise, to
take any and all actions authorized under the Trust Indenture Act in order to
have claims of the Holders and the Trustee allowed in any such proceeding. In
particular, the Trustee shall be authorized to collect and receive any moneys,
securities or other property payable or deliverable upon the exchange of the
Securities or upon any such claims and, subject to the provisions of Article
Fifteen hereof, to distribute the same; and any custodian, receiver, assignee,
trustee, liquidator, sequestrator or other similar official in any such judicial
proceeding is hereby authorized by each Holder to make such payments to the
Trustee and, in the event that the Trustee shall consent to the making of such
payments directly to the Holders, to pay to the Trustee any amount due it for
the reasonable compensation, expenses, disbursements and advances of the
Trustee, its agents and counsel, and any other amounts due the Trustee under
Section 607.

        No provision of this Indenture shall be deemed to authorize the Trustee
to authorize or consent to or accept or adopt on behalf of any Holder any plan
of reorganization, arrangement, adjustment or composition affecting the
Securities or the rights of any Holder thereof or to authorize the Trustee to
vote in respect of the claim of any Holder in any such proceeding; provided,
however, that the Trustee may, on behalf of the Holders, vote for the election
of a trustee in bankruptcy or similar official and be a member of a creditors or
other similar committee.

                                       51
<PAGE>   59
        SECTION 505.  Trustee May Enforce Claims Without Possession of
Securities.

        All rights of action and claims under this Indenture or the Securities
may be prosecuted and enforced by the Trustee without the possession of any of
the Securities or the production thereof in any proceeding relating thereto, and
any such proceeding instituted by the Trustee shall be brought in its own name
as trustee of an express trust, and, subject to the provisions of Article
Fifteen hereof, any recovery of judgment shall, after provision for the payment
of the reasonable compensation, expenses, disbursements and advances of the
Trustee, its agents and counsel, be for the ratable benefit of the Holders of
the Securities in respect of which such judgment has been recovered.

        SECTION 506.  Application of Money Collected.

        Subject to the provisions of Article Fifteen hereof, any money collected
by the Trustee pursuant to this Article shall be applied in the following order,
at the date or dates fixed by the Trustee and, in case of the distribution of
such money on account of principal (or premium, if any) or interest, upon
presentation of the Securities and the notation thereon of the payment if only
partially paid and upon surrender thereof if fully paid:

                FIRST: To the payment of all amounts due the Trustee under
        Section 607; and

                SECOND: To the payment of the amounts then due and unpaid for
        principal of (and premium, if any) and interest on the Securities in
        respect of which or for the benefit of which such money has been
        collected, ratably, without preference or priority of any kind,
        according to the amounts due and payable on such Securities for
        principal (and premium, if any) and interest, respectively.

        The Trustee, upon prior written notice to the Company, may fix a record
date and payment date for any payment to the Holders pursuant to this Section
506.

        SECTION 507.  Limitation on Suits.

        No Holder of any Security shall have any right to institute any
proceeding, judicial or otherwise, with respect to this Indenture, or for the
appointment of a receiver or trustee, or for any other remedy hereunder, unless

                (1) such Holder has previously given written notice to the
        Trustee of a continuing Event of Default;

                (2) the Holders of at least 25% in aggregate principal amount of
        the Outstanding Securities shall have made written request to the
        Trustee to institute proceedings in respect of such Event of Default in
        its own name as Trustee hereunder;

                (3) such Holder or Holders have offered and, if requested,
        provided to the Trustee reasonable indemnity against the costs, expenses
        and liabilities to be incurred in compliance with such request;

                                       52
<PAGE>   60

                (4) the Trustee for 60 days after its receipt of such notice,
        request and offer and, if requested, provision of indemnity has failed
        to institute any such proceeding; and

                (5) no direction inconsistent with such written request has been
        given to the Trustee during such 60-day period by the Holders of a
        majority in principal amount of the Outstanding Securities;

it being understood and intended that no one or more Holders shall have any
right in any manner whatever by virtue of, or by availing of, any provision of
this Indenture to affect, disturb or prejudice the rights of any other Holders,
or to obtain or to seek to obtain priority or preference over any other Holders
or to enforce any right under this Indenture, except in the manner herein
provided and for the equal and ratable benefit of all the Holders.

        SECTION 508.  Unconditional Right of Holders to Receive Principal,
Premium and Interest.

        Notwithstanding any other provision in this Indenture, the Holder of any
Security shall have the right, which is absolute and unconditional, to receive
payment of the principal of (and premium, if any) and (subject to Section 307)
interest on such Security on the respective Stated Maturities expressed in such
Security (or in the case of a Designated Event Offer made by the Company and
required to be accepted as to such Security, on the Designated Event Payment
Date) and to institute suit for the enforcement of any such payment, and such
rights shall not be impaired without the consent of such Holder.

        SECTION 509.  Restoration of Rights and Remedies.

        If the Trustee or any Holder has instituted any proceeding to enforce
any right or remedy under this Indenture and such proceeding has been
discontinued or abandoned for any reason, or has been determined adversely to
the Trustee or to such Holder, then and in every such case, subject to any
determination in such proceeding, the Company, the Trustee and the Holders shall
be restored severally and respectively to their former positions hereunder and
thereafter all rights and remedies of the Trustee and the Holders shall continue
as though no such proceeding had been instituted.

        SECTION 510.  Rights and Remedies Cumulative.

        Except as otherwise provided with respect to the replacement or payment
of mutilated, destroyed, lost or stolen Securities in the last paragraph of
Section 306, no right or remedy herein conferred upon or reserved to the Trustee
or to the Holders is intended to be exclusive of any other right or remedy, and
every right and remedy shall, to the extent permitted by law, be cumulative and
in addition to every other right and remedy given hereunder or now or hereafter
existing at law or in equity or otherwise. The assertion or employment of any
right or remedy hereunder, or otherwise, shall not prevent the concurrent
assertion or employment of any other appropriate right or remedy.

                                       53
<PAGE>   61

        SECTION 511.  Delay or Omission Not Waiver.

        No delay or omission of the Trustee or of any Holder of any Security to
exercise any right or remedy accruing upon any Event of Default shall impair any
such right or remedy or constitute a waiver of any such Event of Default or an
acquiescence therein. Every right and remedy given by this Article or by law to
the Trustee or to the Holders may be exercised from time to time, and as often
as may be deemed expedient, by the Trustee or by the Holders, as the case may
be.

        SECTION 512.  Control by Holders.

        The Holders of a majority in aggregate principal amount of the
Outstanding Securities shall have the right to direct the time, method and place
of conducting any proceeding for any remedy available to the Trustee or
exercising any trust or power conferred on the Trustee, provided that

                (1) such direction shall not be in conflict with any rule of law
        or with this Indenture or expose the Trustee to personal liability (as
        determined in the sole discretion of the Trustee), and

                (2) the Trustee may take any other action deemed proper by the
        Trustee which is not inconsistent with such direction.

The Trustee may refuse, however, to follow any direction that the Trustee, in
its sole discretion, determines may be unduly prejudicial to the rights of
another Holder or that may subject the Trustee to any liability or expense if
the Trustee determines, in its sole discretion, that it lacks indemnification
against such loss or expense.

        SECTION 513.  Waiver of Past Defaults.

        The Holders of not less than a majority in aggregate principal amount of
the Outstanding Securities may on behalf of the Holders of all the Securities by
written notice to the Trustee waive any past default hereunder and its
consequences, except a default

                (1) in the payment of the principal of or interest on any
        Security (including any Security which is required to have been
        purchased pursuant to a Designated Event Offer which has been made by
        the Company), or

                (2) in respect of a covenant or provision hereof which under
        Article Nine cannot be modified or amended without the consent of the
        Holder of each Outstanding Security affected.

                (3) arising from failure to purchase any Security tendered
        pursuant to Section 1201.

        Upon any such waiver, such default shall cease to exist, and any Event
of Default arising therefrom shall be deemed to have been cured, for every
purpose of this Indenture; but no such waiver shall extend to any subsequent or
other default or impair any right consequent thereon.

                                       54
<PAGE>   62

        SECTION 514.  Undertaking for Costs.

        In any suit for the enforcement of any right or remedy under this
Indenture, or in any suit against the Trustee for any action taken or omitted by
it as Trustee, a court may require any party litigant in such suit to file an
undertaking to pay the costs of such suit, and may assess costs against any such
party litigant, in the manner and to the extent provided in the Trust Indenture
Act; provided that neither this Section nor the Trust Indenture Act shall be
deemed to authorize any court to require such an undertaking or to make such an
assessment in any suit instituted by the Company.

        SECTION 515.  Waiver of Stay or Extension Laws.

        The Company covenants (to the extent that it may lawfully do so) that it
will not at any time insist upon, or plead, or in any manner whatsoever claim or
take the benefit or advantage of, any stay or extension law wherever enacted,
now or at any time hereafter in force, which may affect the covenants or the
performance of this Indenture; and the Company (to the extent that it may
lawfully do so) hereby expressly waives all benefit or advantage of any such law
and covenants that it will not hinder, delay or impede the execution of any
power herein granted to the Trustee, but will suffer and permit the execution of
every such power as though no such law had been enacted.

                                  ARTICLE SIX.

                                  THE TRUSTEE

        SECTION 601.  Certain Duties and Responsibilities.

        The duties and responsibilities of the Trustee shall be as provided by
the Trust Indenture Act. Notwithstanding the foregoing, no provision of this
Indenture shall require the Trustee to expend or risk its own funds or otherwise
incur any financial liability in the performance of any of its duties hereunder,
or in the exercise of any of its rights or powers, if it shall have reasonable
grounds for believing that repayment of such funds or adequate indemnity against
such risk or liability is not reasonably assured to it. Whether or not therein
expressly so provided, every provision of this Indenture relating to the conduct
or affecting the liability of or affording protection to the Trustee shall be
subject to the provisions of this Section.

        SECTION 602.  Notice of Defaults.

        The Trustee shall give the Holders notice of any Default hereunder as
and to the extent provided by the Trust Indenture Act, unless such Default has
been cured or waived; provided, however, that in the case of any Default of the
character specified in Section 501(5), no such notice to Holders shall be given
until at least 30 days after the occurrence thereof.

                                       55
<PAGE>   63

        SECTION 603.  Certain Rights of Trustee.

Subject to the provisions of Section 601:

        (a)   the Trustee may rely and shall be protected in acting or
refraining  from acting upon any resolution, certificate, statement,
instrument, opinion, report, notice, request, direction, consent, order, bond,
debenture, note, other evidence of indebtedness or other paper or document
believed by it to be genuine and to have been signed or presented by the proper
party or parties;

        (b)   any request or direction of the Company mentioned herein shall be
sufficiently evidenced by a Company Request or a Company Order and any
resolution of the Board of Directors may be sufficiently evidenced by a Board
Resolution;

        (c)   whenever in the administration of this Indenture the Trustee shall
deem it desirable that a matter be proved or established prior to taking,
suffering or omitting any action hereunder, the Trustee may, in the absence of
bad faith on its part, rely upon an Officers' Certificate or an Opinion of
Counsel;

        (d)   the Trustee may consult with counsel and the written advice of
such counsel or any Opinion of Counsel shall be full and complete authorization
and protection in respect of any action taken, suffered or omitted by it
hereunder in good faith and in reliance thereon;

        (e)   the Trustee shall be under no obligation to exercise any of the
rights or powers vested in it by this Indenture at the request or direction of
any of the Holders pursuant to this Indenture, unless such Holders shall have
offered to the Trustee reasonable security or indemnity against the costs,
expenses and liabilities which might be incurred by it in compliance with such
request or direction reasonably satisfactory to the Trustee;

        (f)   the Trustee shall not be bound to make any investigation into the
facts or matters stated in any resolution, certificate, statement, instrument,
opinion, report, notice, request, direction, consent, order, bond, debenture,
note, other evidence of indebtedness or other paper or document, but the
Trustee, in its discretion, may make such further inquiry or investigation into
such facts or matters as it may see fit, and, if the Trustee shall determine to
make such further inquiry or investigation, it shall be entitled to examine the
books, records and premises of the Company, personally or by agent or attorney;

        (g)   the Trustee may execute any of the trusts or powers hereunder or
perform any duties hereunder either directly or by or through agents or
attorneys and the Trustee shall not be responsible for any misconduct or
negligence on the part of any agent or attorney appointed with due care by it
hereunder; and

        (h)   the Trustee shall not be liable for any action taken, suffered or
omitted by it in good faith which the Trustee reasonably believed to have been
authorized or within its rights or powers.

                                       56
<PAGE>   64

        SECTION 604.  Not Responsible for Recitals or Issuance of Securities.

        The recitals contained herein and in the Securities, except the
Trustee's certificates of authentication, shall be taken as the statements of
the Company, and the Trustee assumes no responsibility for their correctness.
The Trustee makes no representations as to the validity or sufficiency of this
Indenture or the Securities. The Trustee shall not be accountable for the use or
application by the Company of Securities or the proceeds thereof.

        SECTION 605.  May Hold Securities.

        The Trustee, any Paying Agent, any Security Registrar (if other than the
Trustee) or any other agent of the Company, in its individual or any other
capacity, may become the owner or pledgee of Securities and, subject to Sections
608 and 613, may otherwise deal with the Company with the same rights it would
have if it were not Trustee, Paying Agent, Security Registrar or such other
agent.

        SECTION 606.  Money Held in Trust.

        Money held by the Trustee in trust hereunder need not be segregated from
other funds except to the extent required by law. The Trustee shall be under no
liability for interest on any money received by it hereunder except as otherwise
agreed with the Company.

        SECTION 607.  Compensation and Reimbursement.

        The Company agrees

                (1) to pay to the Trustee from time to time reasonable
        compensation for all services rendered by it hereunder (which
        compensation shall not be limited by any provision of law in regard to
        the compensation of a trustee of an express trust);

                (2) except as otherwise expressly provided herein, to reimburse
        the Trustee upon its request for all reasonable expenses, disbursements
        and advances incurred or made by the Trustee in accordance with any
        provision of this Indenture (including the reasonable compensation and
        the expenses and disbursements of its agents and counsel), except any
        such expense, disbursement or advance as may be attributable to its
        negligence or bad faith; and

                (3) to indemnify the Trustee for, and to hold it harmless
        against, any loss, liability or expense (including the reasonable
        compensation, expenses and disbursements of its agents, accountants,
        experts and counsel) incurred without negligence or bad faith on its
        part, arising out of or in connection with the acceptance or
        administration of this trust, including the costs and expenses of
        enforcing this Indenture against the Company (including, without
        limitation, this Section 607) and of defending itself against any claim
        (whether asserted by any Holder or the Company) or liability in
        connection with the exercise or performance of any of its powers or
        duties hereunder. The provisions of this Section 607 shall survive any
        termination of this Indenture and the resignation or removal of the
        Trustee.

                                       57
<PAGE>   65

        As security for the performance of the obligations of the Company under
this Section 607, the Trustee shall have a lien prior to the Securities upon all
property and funds held or collected by the Trustee, except funds held in trust
for the payment of principal of (and premium, if any) or interest on particular
Securities. The Trustee's right to receive payment of any amounts due under this
Section 607 shall not be subordinate to any other liability or indebtedness of
the Company (even though the Securities may be so subordinated).

        When the Trustee incurs expenses or renders services after an Event of
Default specified in Section 501(8) or (9) occurs, the expenses and the
compensation for such services are intended to constitute expenses of
administration under Title 11, U.S. Code, or any similar Federal state or
foreign law for the relief of debtors.

        SECTION 608.  Disqualification; Conflicting Interests.

        If the Trustee has or shall acquire a conflicting interest within the
meaning of the Trust Indenture Act, the Trustee shall either eliminate such
interest or resign, to the extent and in the manner provided by, and subject to
the provisions of, the Trust Indenture Act and this Indenture.

        SECTION 609.  Corporate Trustee Required; Eligibility.

        There shall at all times be a Trustee hereunder which shall be a Person
that is eligible pursuant to the Trust Indenture Act to act as such and has a
combined capital and surplus of at least $50,000,000 and its Corporate Trust
Office in the Borough of Manhattan, The City of New York, New York. If such
Person publishes reports of condition at least annually, pursuant to law or to
the requirements of a Federal, State, Territorial or District of Columbia
supervising or examining authority, then for the purposes of this Section, the
combined capital and surplus of such Person shall be deemed to be its combined
capital and surplus as set forth in its most recent report of condition so
published. If at any time the Trustee shall cease to be eligible in accordance
with the provisions of this Section, it shall resign immediately in the manner
and with the effect hereinafter specified in this Article.

        SECTION 610.  Resignation and Removal; Appointment of Successor.

        (a)   No resignation or removal of the Trustee and no appointment of a
successor Trustee pursuant to this Article shall become effective until the
acceptance of appointment by the successor Trustee under Section 611, at which
time the retiring Trustee shall be fully discharged from its obligations
hereunder.

        (b)   The Trustee may resign at any time by giving written notice
thereof to the Company. If an instrument of acceptance by a successor Trustee
shall not have been delivered to the Trustee within 30 days after the giving of
such notice of resignation, the resigning Trustee may petition any court of
competent jurisdiction for the appointment of a successor Trustee.

        (c)   The Trustee may be removed at any time by Act of the Holders of a
majority in principal amount of the Outstanding Securities, delivered to the
Trustee and to the Company.

                                       58
<PAGE>   66

        (d)   If at any time:

                (1) the Trustee shall fail to comply with Section 608 after
        written request therefor by the Company or by any Holder who has been a
        bona fide Holder of a Security for at least six months, or

                (2) the Trustee shall cease to be eligible under Section 609 and
        shall fail to resign after written request therefor by the Company or by
        any such Holder, or

                (3) the Trustee shall become incapable of acting or shall be
        adjudged a bankrupt or insolvent or a receiver of the Trustee or of its
        property shall be appointed or any public officer shall take charge or
        control of the Trustee or of its property or affairs for the purpose of
        rehabilitation, conservation or liquidation,

then, in any such case, (i) the Company, by Board Resolution, may remove the
Trustee, or (ii) subject to Section 514, any Holder who has been a bona fide
Holder of a Security for at least six months may, on behalf of himself and all
others similarly situated, petition any court of competent jurisdiction for the
removal of the Trustee and the appointment of a successor Trustee.

        (e)   If the Trustee shall resign, be removed or become incapable of
acting, or if a vacancy shall occur in the office of Trustee for any cause, the
Company, by Board Resolution, shall promptly appoint a successor Trustee. If,
within one year after such resignation, removal or incapability, or the
occurrence of such vacancy, a successor Trustee shall be appointed by Act of the
Holders of a majority in principal amount of the Outstanding Securities
delivered to the Company and the retiring Trustee, the successor Trustee so
appointed shall, forthwith upon its acceptance of such appointment, become the
successor Trustee and supersede the successor Trustee appointed by the Company.
If no successor Trustee shall have been so appointed by the Company or the
Holders and accepted appointment in the manner hereinafter provided, any Holder
who has been a bona fide Holder of a Security for at least six months may, on
behalf of himself and all others similarly situated, petition any court of
competent jurisdiction for the appointment of a successor Trustee.

        (f)   The Company shall give notice of each resignation and each
removal  of the Trustee and each appointment of a successor Trustee to all
Holders in the manner provided in Section 106. Each notice shall include the
name of the successor Trustee and the address of its Corporate Trust Office.

        SECTION 611.  Acceptance of Appointment by Successor.

        Every successor Trustee appointed hereunder shall execute, acknowledge
and deliver to the Company and to the retiring Trustee an instrument accepting
such appointment, and thereupon the resignation or removal of the retiring
Trustee shall become effective and such successor Trustee, without any further
act, deed or conveyance, shall become vested with all the rights, powers, trusts
and duties of the retiring Trustee; but, on request of the Company or the
successor Trustee under Section 607, execute and deliver an instrument
transferring to such successor Trustee all the rights, powers and trusts of the
retiring Trustee and shall duly assign, transfer and deliver to such successor
Trustee all property and money held by such retiring Trustee hereunder. Upon
request of any such successor Trustee, the Company shall execute any

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<PAGE>   67

and all instruments for more fully and certainly vesting in and confirming to
such successor Trustee all such rights, powers and trusts.

        No successor Trustee shall accept its appointment unless at the time of
such acceptance such successor Trustee shall be qualified and eligible under
this Article.

        SECTION 612.  Merger, Conversion, Consolidation or Succession to
Business.

        Any corporation into which the Trustee may be merged or converted or
with which it may be consolidated, or any corporation resulting from any merger,
conversion or consolidation to which the Trustee shall be a party, or any
corporation succeeding to all or substantially all the corporate trust business
of the Trustee, shall be the successor of the Trustee hereunder, provided that
such corporation shall be otherwise qualified and eligible under this Article,
without the execution or filing of any paper or any further act on the part of
any of the parties hereto. In case any Securities shall have been authenticated,
but not delivered, by the Trustee then in office, any successor by merger,
conversion or consolidation to such authenticating Trustee may adopt such
authentication and deliver the Securities so authenticated with the same effect
as if such successor Trustee had itself authenticated such Securities.

        SECTION 613.  Preferential Collection of Claims Against the Company.

        If and when the Trustee shall be or become a creditor of the Company (or
any other obligor upon the Securities), the Trustee shall be subject to the
provisions of the Trust Indenture Act regarding the collection of claims against
the Company (or any such other obligor).

        SECTION 614.  Appointment of Authenticating Agent.

        The Trustee may appoint an authenticating agent or agents (an
"Authenticating Agent") with respect to the Securities which shall be authorized
to act on behalf of the Trustee to authenticate Securities issued upon original
issue and upon exchange, registration of transfer or partial repurchase or
conversion thereof or pursuant to Section 306, and Securities so authenticated
shall be entitled to the benefits of this Indenture and shall be valid and
obligatory for all purposes as if authenticated by the Trustee hereunder.
Wherever reference is made in this Indenture to the authentication and delivery
of Securities by the Trustee or the Trustee's certificate of authentication,
such reference shall be deemed to include authentication and delivery on behalf
of the Trustee by an Authenticating Agent and a certificate of authentication
executed on behalf of the Trustee by an Authenticating Agent. Each
Authenticating Agent shall be acceptable to the Company and shall at all times
be a corporation organized and doing business under the laws of the United
States of America, any State thereof or the District of Columbia, authorized
under such laws to act as Authenticating Agent, having a combined capital and
surplus of not less than $50,000,000 and subject to supervision or examination
by Federal or State authority. If such Authenticating Agent publishes reports of
condition at least annually, pursuant to law or to the requirements of said
supervising or examining authority, then for the purposes of this Section, the
combined capital and surplus of such Authenticating Agent shall be deemed to be
its combined capital and surplus as set forth in its most recent report of
condition so published. If at any time an Authenticating Agent shall cease to be
eligible in accordance with

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<PAGE>   68

the provisions of this Section, such Authenticating Agent shall resign
immediately in the manner and with the effect specified in this Section.

        Any corporation into which an Authenticating Agent may be merged or
converted or with which it may be consolidated, or any corporation resulting
from any merger, conversion or consolidation to which such Authenticating Agent
shall be a party, or any corporation succeeding to the corporate agency or
corporate trust business of an Authenticating Agent, shall continue to be an
Authenticating Agent, provided such corporation shall be otherwise eligible
under this Section, without the execution or filing of any paper or any further
act on the part of the Trustee or the Authenticating Agent.

        An Authenticating Agent may resign at any time by giving written notice
thereof to the Trustee and to the Company. The Trustee may at any time terminate
the agency of an Authenticating Agent by giving written notice thereof to such
Authenticating Agent and to the Company. Upon receiving such a notice of
resignation or upon such a termination, or in case at any time such
Authenticating Agent shall cease to be eligible in accordance with the
provisions of this Section, the Trustee may appoint a successor Authenticating
Agent which shall be acceptable to the Company and shall give notice of such
appointment in the manner provided in Section 106 to all Holders of Securities.
Any successor Authenticating Agent upon acceptance of its appointment hereunder
shall become vested with all the rights, powers and duties of its predecessor
hereunder, with like effect as if originally named as an Authenticating Agent.
No successor Authenticating Agent shall be appointed unless eligible under the
provisions of this Section.

        The Trustee agrees to pay to each Authenticating Agent from time to time
reasonable compensation for its services under this Section, and the Trustee
shall be entitled to be reimbursed for such payments, subject to the provisions
of Section 607.

        If an appointment is made pursuant to this Section, the Securities may
have endorsed thereon, in lieu of the Trustee's certificate of authentication,
an alternative certificate of authentication in the following form:

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

                                    United States Trust Company of New York,
                                                                     As Trustee

                                    By
                                      --------------------------
                                      As Authenticating Agent

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

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<PAGE>   69

                                 ARTICLE SEVEN.

            HOLDERS' LISTS AND REPORTS BY TRUSTEE AND THE COMPANY

        SECTION 701.  Company to Furnish Trustee Names and Addresses of Holders.

        The Company will furnish or cause to be furnished to the Trustee

        (a)   semi-annually, not more than 15 days after each Regular Record
Date, a list, in such form as the Trustee may reasonably require, of the names
and addresses of the Holders as of such Regular Record Date, and

        (b)   at such other times as the Trustee may request in writing, within
30 days after the receipt by the Company of any such request, a list of similar
form and content as of a date not more than 15 days prior to the time such list
is furnished;

excluding from any such list names and addresses received by the Trustee in its
capacity as Security Registrar.

        SECTION 702.  Preservation of Information; Communications to Holders.

        (a)   The Trustee shall preserve, in as current a form as is reasonably
practicable, the names and addresses of Holders contained in the most recent
list furnished to the Trustee as provided in Section 701 and the names and
addresses of Holders received by the Trustee in its capacity as Security
Registrar. The Trustee may destroy any list furnished to it as provided in
Section 701 upon receipt of a new list so furnished.

        (b)   The rights of Holders to communicate with other Holders with
respect to their rights under this Indenture or under the Securities, and the
corresponding rights and duties of the Trustee, shall be as provided by the
Trust Indenture Act.

        (c)   Every Holder of Securities, by receiving and holding the same,
agrees with the Company and the Trustee that none of the Company, the Trustee or
any agent of any of them shall be held accountable by reason of any disclosure
of information as to names and addresses of Holders made pursuant to the Trust
Indenture Act.

        SECTION 703.  Reports by Trustee.

        (a)   The Trustee shall transmit to Holders such reports concerning the
Trustee and its actions under this Indenture as may be required pursuant to the
Trust Indenture Act at the times and in the manner provided pursuant thereto.

        (b)   A copy of each such report shall, at the time of such
transmission to Holders, be filed by the Trustee with each stock exchange upon
which the Securities are listed, with the Commission and with the Company. The
Company will notify the Trustee when the Securities are listed on any stock
exchange.

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<PAGE>   70

        SECTION 704.  Reports by Company.

        The Company shall file with the Trustee and the Commission, and
transmit  to Holders, such information, documents and other reports, and such
summaries thereof, as may be required pursuant to the Trust Indenture Act at
the times and in the manner provided pursuant to such Act and in the manner set
forth in Section 1006; provided that any such information, documents or reports
required to be filed with the Commission pursuant to Section 13 or 15(d) of the
Exchange Act ("SEC Reports") shall be filed with the Trustee within 15 days
after the same is so required to be filed with the Commission. In the event the
Company shall cease to be required to file SEC Reports pursuant to the Exchange
Act, the Company will nonetheless continue to file such reports with the
Commission (unless the Commission will not accept such a filing) and the
Trustee and to furnish copies of such SEC Reports to the Holders of Securities
at the time the Company is required to file such reports with the Trustee and
will make such information available to investors who request it in writing.

        SECTION 705.  Officers' Certificate with Respect to Change in Interest
Rates.

        Within five days after any Step-Up, Subsequent Step-Up, Step-Down Date
or Subsequent Step-Down Date, the Company shall deliver an Officers' Certificate
to the Trustee stating the new interest rate and the date on which it became
effective.

                                 ARTICLE EIGHT.

                           MERGER, CONSOLIDATION, ETC.

        SECTION 801.  Mergers, Consolidations and Certain Sales of Assets.

        The Company may not, in a single transaction or a series of related
transactions, (i) consolidate with or merge into any other Person or permit any
other Person to consolidate with or merge into the Company (other than a
consolidation or merger of a wholly owned subsidiary organized under the laws of
a state of the United States into the Company), or (ii) directly or indirectly,
transfer, sell, lease or otherwise dispose of all or substantially all of its
assets (determined on a consolidated basis for the Company and its Restricted
Subsidiaries taken as a whole and provided that the creation of a lien on or in
any of its assets shall not in and of itself constitute the transfer, sale,
lease or disposition of the assets subject to the lien), unless: (1) in a
transaction in which the Company does not survive or in which the Company sells,
leases or otherwise disposes of all or substantially all of its assets to any
other Person, the successor entity to the Company shall be a corporation,
limited liability company or business trust organized under the laws of the
United States of America or any State thereof or the District of Columbia and
shall expressly assume, by a supplemental indenture executed and delivered to
the Trustee in form satisfactory to the Trustee, all of the Company's
obligations under this Indenture; (2) immediately after giving effect to such
transaction, no Default or Event of Default shall have occurred and be
continuing; and (3) the Company has delivered to the Trustee an Officers'
Certificate and an Opinion of Counsel, each in form and substance satisfactory
to the Trustee stating that such consolidation, merger, conveyance, transfer,
lease or acquisition and, if a

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<PAGE>   71

supplemental indenture is required in connection with such transaction, such
supplemental indenture, complies with this Article and that all conditions
precedent herein provided for relating to such transaction have been complied
with.

        SECTION 802.  Successor Substituted.

        Upon any consolidation of the Company with, or merger of the Company
with or into, any other Person or any conveyance, transfer or lease of the
properties and assets of the Company substantially as an entirety in accordance
with Section 801, the successor Person formed by such consolidation or into
which the Company is merged or to which such conveyance, transfer or lease is
made shall succeed to, and be substituted for, and may exercise every right and
power of, the Company under this Indenture with the same effect as if such
successor Person had been named as the Company herein, and thereafter, except in
the case of a lease, the predecessor Person shall be relieved of all obligations
and covenants under this Indenture and the Securities.

                                 ARTICLE NINE.

                             SUPPLEMENTAL INDENTURES

        SECTION 901.  Supplemental Indentures Without Consent of Holders.

        Without the consent of any Holders, the Company, when authorized by
Board Resolution, and the Trustee, at any time and from time to time, may enter
into one or more indentures supplemental hereto, in form satisfactory to the
Trustee, for any of the following purposes:

                (1) to cure any ambiguity, defect or inconsistency;

                (2) to provide for uncertificated Securities in addition to or
        in place of certificated Securities;

                (3) to provide for the assumption of the obligations to Holders
        of Securities in the case of a merger or consolidation;

                (4) to provide for conversion rights of Holders of Securities in
        certain events such as a consolidation, merger or sale of all or
        substantially all of the Company's assets;

                (5) to reduce the Conversion Rate;

                (6) make any change that would provide any additional rights or
        benefits to Holders of Securities or that does not adversely affect the
        legal rights under the Indenture of any such Holder; or

                (7) comply with requirements of the Commission in order to
        maintain the qualification of the Indenture under the Trust Indenture
        Act of 1939, as amended.

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<PAGE>   72

        SECTION 902.  Supplemental Indentures with Consent of Holders.

        With the consent of the Holders of not less than a majority in aggregate
principal amount of the Outstanding Securities, by Act of said Holders delivered
to the Company and the Trustee, and consistent with Section 513, the Company,
when authorized by Board Resolution, and the Trustee may enter into an indenture
or indentures supplemental hereto for the purpose of adding any provisions to or
changing in any manner or eliminating any of the provisions of this Indenture or
of modifying in any manner the rights of the Holders under this Indenture;
provided, however, that no such supplemental indenture shall, without the
consent of the Holder of each Outstanding Security affected thereby,

                (1) change the due date of the principal of, or any installment
        of interest on, any Security;

                (2) reduce the principal amount of, or interest on, Securities;

                (3) change the place or currency of payment of principal of, or
        interest on, any Security;

                (4) impair the right to institute suit for the enforcement of
        any payment on or with respect to any Security;

                (5) reduce the above stated percentage of outstanding Securities
        necessary to modify or amend the Indenture;

                (6) reduce the percentage of aggregate principal amount of
        outstanding Securities necessary for waiver of compliance with certain
        provisions of the Indenture or for waiver of certain defaults;

                (7) modify any provisions of the Indenture relating to the
        modification and amendment of the Indenture or the waiver of past
        defaults or covenants, except as otherwise specified;

                (8) following the mailing of any notice of a Designated Event
        Offer, modify such Designated Event Offer in a manner materially adverse
        to the Holders of Securities; or

                (9) except as permitted by the Indenture, increase the
        Conversion Price or, other than as set forth in Section 901, modify the
        provisions of the Indenture relating to conversion of the Securities in
        a manner adverse to the Holders thereof.

        It shall not be necessary for any Act of Holders under this Section to
approve the particular form of any proposed supplemental indenture, but it shall
be sufficient if such Act shall approve the substance thereof.

        SECTION 903.  Execution of Supplemental Indentures.

        In executing, or accepting the additional trusts created by, any
supplemental indenture permitted by this Article or the modifications thereby of
the trusts created by this Indenture, the

                                       65
<PAGE>   73

Trustee shall be entitled to receive, and (subject to Section 601) shall be
fully protected in relying upon, an Opinion of Counsel stating that the
execution of such supplemental indenture is authorized or permitted by this
Indenture. The Trustee may, but shall not be obligated to, enter into any such
supplemental indenture which affects the Trustee's own rights, duties or
immunities under this Indenture or otherwise.

        SECTION 904.  Effect of Supplemental Indentures.

        Upon the execution of any supplemental indenture under this Article,
this Indenture shall be modified in accordance therewith, and such supplemental
indenture shall form a part of this Indenture for all purposes; and every Holder
of Securities theretofore or thereafter authenticated and delivered hereunder
shall be bound thereby.

        SECTION 905.  Conformity with Trust Indenture Act.

        Every supplemental indenture executed pursuant to this Article shall
conform to the requirements of the Trust Indenture Act.

        SECTION 906.  Reference in Securities to Supplemental Indentures.

        Securities authenticated and delivered after the execution of any
supplemental indenture pursuant to this Article may, and shall if required by
the Trustee, bear a notation in form approved by the Trustee as to any matter
provided for in such supplemental indenture. If the Company shall so determine,
new Securities so modified as to conform, in the opinion of the Trustee and the
Company, to any such supplemental indenture may be prepared and executed by the
Company and authenticated and delivered by the Trustee in exchange for
Outstanding Securities.

                                  ARTICLE TEN.

                                   COVENANTS

        SECTION 1001. Payment of Principal, Premium and Interest.

        The Company will duly and punctually pay the principal of and premium,
if any, and interest, including any Liquidated Damages, on the Securities in
accordance with the terms of the Securities and this Indenture.

        SECTION 1002. Maintenance of Office or Agency.

        The Company will maintain in the Borough of Manhattan, The City of New
York, New York, an office or agency where Securities may be presented or
surrendered for payment, where Securities may be surrendered for registration of
transfer or exchange, where Securities may be surrendered for conversion and
where notices and demands to or upon the Company in respect of the Securities
and this Indenture may be served. The Company will give prompt written notice to
the Trustee of the location, and any change in the location, of such office or
agency. If at any

                                       66
<PAGE>   74

time the Company shall fail to maintain any such required office or agency or
shall fail to furnish the Trustee with the address thereof, such presentations,
surrenders, notices and demands may be made or served at the Corporate Trust
Office of the Trustee, and the Company hereby appoints the Trustee as its agent
to receive all such presentations, surrenders, notices and demands.

        The Company may also from time to time designate one or more other
offices or agencies (in or outside the Borough of Manhattan, The City of New
York, New York) where the Securities may be presented or surrendered for any or
all such purposes and may from time to time rescind such designations; provided,
however, that no such designation or rescission shall in any manner relieve the
Company of its obligation to maintain an office or agency in the Borough of
Manhattan, The City of New York, New York for such purposes. The Company will
give prompt written notice to the Trustee of any such designation or rescission
and of any change in the location of any such other office or agency.

        SECTION 1003. Money for Security Payments to be Held in Trust.

        If the Company shall at any time act as its own Paying Agent, it will,
on or before each due date of the principal of (and premium, if any) or interest
on any of the Securities, segregate and hold in trust for the benefit of the
Persons entitled thereto a sum sufficient to pay the principal (and premium, if
any) or interest so becoming due until such sums shall be paid to such Persons
or otherwise disposed of as herein provided and will promptly notify the Trustee
in writing of its action or failure so to act. As provided in Section 504, upon
any bankruptcy or reorganization proceeding relative to the Company, the Trustee
shall serve as the Paying Agent for the Securities.

        Whenever the Company shall have one or more Paying Agents, it will,
prior to each due date of the principal of (and premium, if any) or interest on
any Securities, deposit with a Paying Agent a sum sufficient to pay the
principal (and premium, if any) or interest so becoming due, such sum to be held
in trust for the benefit of the Persons entitled to such principal, premium or
interest, and (unless such Paying Agent is the Trustee) the Company will
promptly notify the Trustee in writing of its action or failure so to act. As
provided in Section 504, upon any bankruptcy or reorganization proceeding
relative to the Company the Trustee shall serve as the Paying Agent for the
Securities.

        The Company will cause each Paying Agent other than the Trustee to
execute and deliver to the Trustee an instrument in which such Paying Agent
shall agree with the Trustee, subject to the provisions of this Section, that
such Paying Agent will:

                (1) hold all sums held by it for the payment of the principal of
        (and premium, if any) or interest on Securities in trust for the benefit
        of the Persons entitled thereto until such sums shall be paid to such
        Persons or otherwise disposed of as herein provided;

                (2) give the Trustee notice of any default by the Company (or
        any other obligor upon the Securities) in the making of any payment of
        principal (and premium, if any) or interest;

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<PAGE>   75
                (3) at any time during the continuance of any such default, upon
        the written request of the Trustee, forthwith pay to the Trustee all
        sums so held in trust by such Paying Agent; and

                (4) acknowledge, accept and agree to comply in all respects with
        the provisions of this Indenture relating to the duties, rights and
        obligations of such Paying Agent.

        The Company may at any time, for the purpose of obtaining the
satisfaction and discharge of this Indenture or for any other purpose, pay, or
by Company Order direct any Paying Agent to pay, to the Trustee all sums held in
trust by the Company or such Paying Agent, such sums to be held by the Trustee
upon the same trusts as those upon which such sums were held by the Company or
such Paying Agent; and, upon such payment by any Paying Agent to the Trustee,
such Paying Agent shall be released from all further liability with respect to
such money.

        Any money deposited with the Trustee or any Paying Agent, or then held
by the Company, in trust for the payment of the principal of (and premium, if
any) or interest on any Security and remaining unclaimed for two years after
such principal (and premium, if any) or interest has become due and payable
shall be paid to the Company on the Company Request, or (if then held by the
Company) shall be discharged from such trust; and the Holder of such Security
shall thereafter, as an unsecured general creditor, look only to the Company for
payment thereof, and all liability of the Trustee or such Paying Agent with
respect to such trust money, and all liability of the Company as trustee
thereof, shall thereupon cease; provided, however, that the Trustee or such
Paying Agent, before being required to make any such repayment, may at the
expense of the Company cause to be published once, in a newspaper published in
the English language, customarily published on each Business Day and of general
circulation in the Borough of Manhattan, The City of New York, New York, notice
that such money remains unclaimed and that, after a date specified therein,
which shall not be less than 30 days from the date of such publication, any
unclaimed balance of such money then remaining will be repaid to the Company.

        SECTION 1004. Existence.

        Subject to Article Eight, the Company will do or cause to be done all
things necessary to preserve and keep in full force and effect its existence,
rights (charter and statutory) and franchises; provided, however, that the
Company shall not be required to preserve any such right or franchise if the
Board of Directors shall determine that the preservation thereof is no longer
desirable in the conduct of the business of the Company and that the loss
thereof is not disadvantageous in any material respect to the Holders.

        SECTION 1005. Maintenance of Properties and Insurance.

        The Company will cause all properties used or useful in the conduct of
its business or the business of any subsidiary, to be maintained and kept in
good condition, repair and working order and supplied with all necessary
equipment and will cause to be made all necessary repairs, renewals,
replacements, betterments and improvements thereof, all as in the judgment of
the Company may be necessary so that the business carried on in connection
therewith ay be

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<PAGE>   76

properly and advantageously conducted at all timed; provided, however, that
nothing in this Section 1005 shall prevent the Company from discontinuing
operation or maintenance of any of such properties if such discontinuance is, as
determined in the good faith judgment of the Company, desireable in the conduct
of its business or, in the case of the Company, the business of any subsidiary,
and not disadvantageous in any material respect to the Holders of Securities.

        SECTION 1006. Provision of Financial Information.

        The Company has agreed to file with the Trustee, within 15 days after it
files them with the Commission, copies of the SEC Reports. In the event the
Company shall cease to be required to file SEC Reports pursuant to the Exchange
Act, the Company will nevertheless continue to file such reports with the
Commission (unless the Commission will note accept such a filing) and the
Trustee. The Company will furnish copies of the SEC Reports to the Holders of
Securities at the time the Company is required to file the same with the Trustee
and will make such information available to investors who request it in writing.

        SECTION 1007. Rule 144A Information Requirement.

        If at any time there are Transfer Restricted Securities outstanding and
the Company shall cease to have a class of equity securities registered under
Section 12(g) of the Exchange Act or shall cease to be subject to Section 15(d)
of the Exchange Act, the Company shall furnish to the Holders or beneficial
holders of the Securities or the underlying Common Stock and prospective
purchasers of Securities or the underlying Common Stock designated by the
Holders of Transfer Restricted Securities (as defined in the Registration Rights
Agreement), upon their request, the information required to be delivered
pursuant to Rule 144A(d)(4) under the Securities Act until such time as a Shelf
Registration Statement (as defined in the Registration Rights Agreement) has
become effective under the Securities Act. The Company shall also furnish such
information during the pendency of any suspension of effectiveness of a Shelf
Registration Statement.

        SECTION 1008. Statement by Officers as to Default.

        (a)   The Company will deliver to the Trustee within 90 days after the
end of each quarter of each fiscal year of the Company ending after the date
hereof, an Officers' Certificate, stating whether or not to the best knowledge
of the signers thereof the Company is in default in the performance and
observance of any of the terms, provisions and conditions of this Indenture and
if the Company shall be in default, specifying all such defaults and the nature
and status thereof of which they may have knowledge.

        (b)   The Company shall deliver to the Trustee, as soon as possible and
in any event within 10 days after the Company becomes aware of the occurrence of
a Default or an Event of Default, an Officers' Certificate setting forth the
details of such Default or Event of Default and the action which the Company
proposes to take with respect thereto.

        SECTION 1009. Waiver of Certain Covenants and Obligations.

        The Company may omit in any particular instance to comply with any
covenant or condition set forth in Sections 1004, 1005, 1006, 1007 and 1008 and
in Article Twelve if before or after the time for such compliance the Holders of
at least a majority in aggregate principal

                                       69
<PAGE>   77

amount of the Outstanding Securities shall, by Act of such Holders, either waive
such compliance in such instance or generally waive compliance with such
covenant or condition, but no such waiver shall extend to or affect such
covenant or condition except to the extent so expressly waived, and, until such
waiver shall become effective, the obligations of the Company and the duties of
the Trustee in respect of any such covenant or condition shall remain in full
force and effect.

                                ARTICLE ELEVEN.

                       DEFEASANCE AND COVENANT DEFEASANCE

        SECTION 1101. Company's Option to Effect Defeasance or Covenant
Defeasance.

        The Company may, at its option by Board Resolution at any time (subject
to 10-day prior written notification to the Trustee), elect to have either
Section 1102 or Section 1103 applied to the Outstanding Securities upon
compliance with the conditions set forth below in this Article Eleven.

        SECTION 1102. Defeasance and Discharge.

        Upon the Company's exercise of the option provided in Section 1101
applicable to this Section, the Company shall be deemed to have been discharged
from its obligations with respect to the Outstanding Securities on the date the
conditions set forth below are satisfied (hereinafter, "defeasance"). For this
purpose, such defeasance means that the Company shall be deemed to have paid and
discharged the entire indebtedness represented by the Outstanding Securities and
to have satisfied all its other obligations under such Securities and this
Indenture insofar as such Securities are concerned (and the Trustee, at the
expense of the Company, shall execute proper instruments acknowledging the
same), except for the following which shall survive until otherwise terminated
or discharged hereunder:

                (A) the rights of Holders of Outstanding Securities to receive,
        solely from the trust fund described in Section 1104 and as more fully
        set forth in such Section, payments in respect of the principal of (and
        premium, if any) and interest on such Securities when such payments are
        due,

                (B) the Company's obligations with respect to such Securities
        under Sections 304, 305, 306, 1002 and 1003,

                (C) the rights, powers, trusts, duties and immunities of the
        Trustee hereunder and

                (D) this Article Eleven. Subject to compliance with this Article
        Eleven, the Company may exercise its option under this Section 1102
        notwithstanding the prior exercise of its option under Section 1103.

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        SECTION 1103. Covenant Defeasance.

        Upon the Company's exercise of the option provided in Section 1101
applicable to this Section

                (i) the Company shall be released from its obligations under
        Sections 1005 through 1008, inclusive, and 1201,

                (ii) the occurrence of an event specified in Sections 501(1),
        501(3), and 501(4) shall not be deemed to be an Event of Default, on and
        after the date the conditions set forth below are satisfied
        (hereinafter, "covenant defeasance"). For this purpose, such covenant
        defeasance means that the Company may omit to comply with and shall have
        no liability in respect of any term, condition or limitation set forth
        in any such Section or Article, whether directly or indirectly by reason
        of any reference elsewhere herein to any such Section or Article or by
        reason of any reference in any such Section or Article to any other
        provision herein or in any other document, but the remainder of this
        Indenture and such Securities shall be unaffected thereby.

        SECTION 1104. Conditions to Defeasance or Covenant Defeasance.

        The following shall be the conditions to application of either Section
1102 or Section 1103 to the Outstanding Securities:

                (1) The Company shall irrevocably have deposited or caused to be
        deposited with the Trustee as trust funds in trust for the purpose of
        making the following payments, specifically pledged as security for, and
        dedicated solely to, the benefit of the Holders of such Securities,

                        (A) money in an amount, or

                        (B) U.S. Government Obligations which through the
                scheduled payment of principal and interest in respect thereof
                in accordance with their terms will provide, not later than one
                day before the due date of any payment, money in an amount, or

                        (C) a combination thereof, sufficient, in the opinion of
                a nationally recognized firm of independent certified public
                accountants expressed in a written certification thereof
                delivered to the Trustee, to pay and discharge, and which shall
                be applied by the Trustee to pay and discharge, the principal
                of, premium, if any, and each installment of interest on the
                Securities on the Stated Maturity of such principal or
                installment of interest on the day on which such payments are
                due and payable in accordance with the terms of this Indenture
                and of such Securities. For this purpose, "U.S. Government
                Obligations" means securities that are

                                (x) direct obligations of the United States of
                        America for the payment of which its full faith and
                        credit is pledged or

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<PAGE>   79

                             (y) obligations of a Person controlled or
                      supervised by and acting as an agency or instrumentality
                      of the United States of America the payment of which is
                      unconditionally guaranteed as a full faith and credit
                      obligation by the United States of America, which, in
                      either case, are not callable or redeemable at the option
                      of the issuer thereof, and shall also include a depositary
                      receipt issued by a bank (as defined in Section 3(a)(2) of
                      the Securities Act) as custodian with respect to any such
                      U.S. Government Obligation or a specific payment of
                      principal of or interest on any such U.S. Government
                      Obligation held by such custodian for the account of the
                      holder of such depositary receipt, provided that (except
                      as required by law) such custodian is not authorized to
                      make any deduction from the amount payable to the holder
                      of such depositary receipt from any amount received by the
                      custodian in respect of the U.S. Government Obligation or
                      the specific payment of principal of or interest on the
                      U.S. Government Obligation evidenced by such depositary
                      receipt.

                (2) No Default or Event of Default shall have occurred and be
        continuing on the date of such deposit and after giving effect thereto
        or, in connection with an election under Section 1102 insofar as
        subsections 501(8) and (9) are concerned, at any time during the period
        ending on the 91st day after the date of such deposit (it being
        understood that this condition shall not be deemed satisfied until the
        expiration of such period).

                (3) Such defeasance or covenant defeasance shall not cause the
        Trustee to have a conflicting interest as defined in Section 608 and for
        purposes of the Trust Indenture Act with respect to any securities of
        the Company.

                (4) Such defeasance or covenant defeasance shall not result in a
        breach or violation of, or constitute a default under, this Indenture or
        any other agreement or instrument to which the Company is a party or by
        which it is bound.

                (5) The Company shall have delivered to the Trustee an Officers'
        Certificate and an Opinion of Counsel, each stating that all conditions
        precedent provided for relating to either the defeasance under Section
        1102 or the covenant defeasance under Section 1103 (as the case may be)
        have been complied with.

                (6) In the case of an election under Section 1102, the Company
        shall have delivered to the Trustee an Opinion of Counsel stating that

                                (x) the Company has received from, or there has
                        been published by, the Internal Revenue Service a
                        ruling, or

                                (y) since the date of this Indenture there has
                        been a change in the applicable Federal income tax law,
                        in either case to the effect that, and based thereon
                        such opinion shall confirm that, the Holders of the
                        Outstanding Securities will not recognize income, gain
                        or loss for Federal income tax purposes as a result of
                        such deposit, defeasance and discharge

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<PAGE>   80

                        and will be subject to Federal income tax on the same
                        amounts, in the same manner and at the same times as
                        would have been the case if such deposit, defeasance and
                        discharge had not occurred.

                (7) In the case of an election under Section 1103, the Company
        shall have delivered to the Trustee an Opinion of Counsel to the effect
        that the Holders of the Outstanding Securities will not recognize
        income, gain or loss for Federal income tax purposes as a result of such
        deposit and covenant defeasance and will be subject to Federal income
        tax on the same amounts, in the same manner and at the same times as
        would have been the case if such covenant defeasance had not occurred.

                (8) The Company shall have delivered to the Trustee an Opinion
        of Counsel to the effect that such deposit and defeasance or covenant
        defeasance shall not result in the trust arising from such deposit
        constituting an investment company as defined in the Investment Company
        Act of 1940, as amended, or such trust shall be qualified under such act
        or exempt from regulation thereunder.

SECTION 1105. Deposited Money and U.S. Government Obligations to Be Held in
Trust; Other Miscellaneous Provisions.

        Subject to the provisions of the last paragraph of Section 1003, all
money and U.S. Government Obligations (including the proceeds thereof) deposited
with the Trustee (or other qualifying trustee--collectively, for purposes of
this Section 1105, the "Trustee") pursuant to Section 1104 in respect of the
Securities shall be held in trust and applied by the Trustee, in accordance with
the provisions of such Securities and this Indenture, to the payment, either
directly or through any Paying Agent (including the Company acting as its own
Paying Agent) as the Trustee may determine, to the Holders of such Securities,
of all sums due and to become due thereon in respect of principal (and premium,
if any) and interest, but such money need not be segregated from other funds
except to the extent required by law.

        The Company shall pay and indemnify the Trustee against any tax, fee or
other charge imposed on or assessed against the U.S. Government Obligations
deposited pursuant to Section 1104 or the principal and interest received in
respect thereof other than any such tax, fee or other charge which by law is for
the account of the Holders of the Outstanding Securities.

        Anything in this Article Eleven to the contrary notwithstanding, the
Trustee shall deliver or pay to the Company from time to time upon Company
Request any money or U.S. Government Obligations held by it as provided in
Section 1104 which, in the opinion of a nationally recognized accounting firm
expressed in a written certification thereof delivered to the Trustee, are in
excess of the amount thereof which would then be required to be deposited to
effect an equivalent defeasance or covenant defeasance.

        SECTION 1106. Reinstatement.

        If the Trustee or the Paying Agent is unable to apply any money in
accordance with Section 1102 or 1103 by reason of any order or judgment of any
court or governmental authority enjoining, restraining or otherwise prohibiting
such application, then the Company's obligations under this Indenture and the
Securities shall be revived and reinstated as though no deposit had

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<PAGE>   81

occurred pursuant to this Article Eleven until such time as the Trustee or
Paying Agent is permitted to apply all such money in accordance with Section
1102 and 1103; provided, however, that if the Company makes any payment of
principal of (and premium, if any) any Security following the reinstatement of
its obligations, the Company shall be subrogated to the rights of the Holders of
such Securities to receive such payment from the money held by the Trustee or
the Paying Agent.

        SECTION 1107. Repayment to Company.

        Any money deposited with the Trustee or any Paying Agent, or then held
by the Company, in trust for the payment of the principal of, premium, if any,
or interest on any Security and remaining unclaimed for two years after such
principal, and premium, if any, or interest has become due and payable shall be
paid to the Company on its written request or (if then held by the Company)
shall be discharged from such trust; and the Holder of such security shall
thereafter, as a creditor, look only to the Company for payment thereof, and all
liability of the Trustee or such Paying Agent with respect to such trust money,
and all liability of the Company as trustee thereof, shall thereupon cease;
provided, however, that the Trustee or such Paying Agent, before being required
to make any such repayment, may at the expense of the Company cause to be
published once, in the New York Times and The Wall Street Journal (national
edition), notice that such money remains unclaimed and that, after a date
specified therein, which shall not be less than 30 days from the date of such
notification or publication, any unclaimed balance of such money then remaining
will be repaid to the Company.

                                ARTICLE TWELVE.

                      REPURCHASE AT THE OPTION OF HOLDERS

        SECTION 1201. Right to Require Repurchase.

        (a)   Upon the occurrence of a Change of Control, or, following the
termination of the Credit Agreement or if the lenders thereunder have waived
certain restrictions with respect to the incurrence of indebtedness under
Section 6.1 thereof as such restrictions relate to the incurrence of
Indebtedness evidenced by the Securities (a "Waiver"), a Termination of Trading,
each Holder shall have the right, at the Holder's option, to require the
Company, subject to certain limitations set forth herein, to repurchase the
Securities at a purchase price in cash in an amount equal to 100% of the
principal amount thereof, plus accrued and unpaid interest and Liquidated
Damages to the Designated Event Payment Date (subject to the right of Holders of
record on the Regular Record Date next preceding the Designated Event Payment
Date to receive interest due on the next Interest Payment Date). At the option
of the Company, the Purchase Price may be paid in cash or, subject to the
conditions set forth in Section 1202, by delivery of shares of Class A Common
Stock of the Company having a fair market value equal to the Purchase Price. For
purposes of this paragraph, the fair market value of shares of Class A Common
Stock of the Company shall be determined by the Company and shall be equal to
95% of the average of the Current Market Price for the five consecutive Trading
Days that immediately precede and end on and include the third Trading Day prior
to the Designated Event Payment Date.

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<PAGE>   82

        (b)   If the Designated Event is a Change of Control, holders of the
Securities will not have the right set forth in clause (a) hereof if: (i) the
daily market price per share of the Class A Common Stock for any five Trading
Days within the period of 10 consecutive Trading Days ending immediately after
the later of the Change of Control or the public announcement thereof or, if the
Change of Control results in the reclassification, conversion or exchange of
outstanding shares of Class A Common Stock, within the period of 10 consecutive
Trading Days ending immediately before the Change of Control, shall equal or
exceed 105% of the Conversion Price of the Securities in effect on the date of
the Change of Control or the public announcement thereof, as applicable, or (ii)
at least 90% of the consideration received by holders of Class A Common Stock
(or other Capital Stock into which the Securities are then convertible) in the
Change of Control transaction consists of shares of Capital Stock traded on a
U.S. national securities exchange or quoted on the NASDAQ National Market, and
as a result of the transaction, the Securities become convertible into such
consideration.

        (c)   Within 30 days of the occurrence of a Change of Control, the
Company will be required to make a Designated Event Offer to purchase all
Outstanding Securities at a price, subject to the next sentence, in cash equal
to 100% of the principal amount of the Securities on the Designated Event
Payment Date, plus accrued and unpaid interest to such Designated Event Payment
Date (subject to the right of Holders of record on the Regular Record Date next
preceding the Designated Event Payment Date to receive interest due on the next
Interest Payment Date). At the option of the Company, the Purchase Price may be
paid in cash or, subject to the fulfillment by the Company of the conditions set
forth in Section 1202 hereof, by delivery of shares of Common Stock of the
Company having a fair market value equal to the Purchase Price.

        (d)   The Company and the Trustee shall perform their respective
obligations for the Designated Event Offer as specified in the Offer. Prior to
the Designated Event Payment Date, the Company shall (i) accept for payment
Securities or portions thereof tendered pursuant to the Offer, (ii) irrevocably
deposit with the Paying Agent (or, if the Company is acting as its own Paying
Agent, segregate and hold in trust as provided in Section 1003) cash or shares
of Common Stock of the Company, as provided below, sufficient to pay the
Purchase Price of all Securities or portions thereof so accepted (provided that
such deposit may be made no later than 10:00 A.M. New York City time on the
Designated Event Payment Date if the Company elects) and (iii) deliver or cause
to be delivered to the Trustee all Securities so accepted together with an
Officers' Certificate stating the Securities or portions thereof accepted for
payment by the Company. The Paying Agent shall promptly mail or deliver to
Holders of Securities so accepted payment or shares of Common Stock of the
Company in an amount equal to the Purchase Price, and the Trustee shall promptly
authenticate and mail or deliver to such Holders a new Security or Securities
equal in principal amount to any unpurchased portion of the principal amount of
the Security surrendered as requested by the Holder. Any Security not accepted
for payment shall be promptly mailed or delivered by the Company to the Holder
thereof. In the event that the aggregate Purchase Price is less than the amount
delivered by the Company to the Trustee or the Paying Agent, the Trustee or the
Paying Agent, as the case may be, shall deliver the excess to the Company
immediately after the Designated Event Payment Date.

        (g)   Any issuance of shares of Common Stock of the Company in respect
of the Purchase Price shall be deemed to have been effected immediately prior to
the close of business

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<PAGE>   83

on the Designated Event Payment Date and the Person or Persons in whose name or
names any certificate or certificates for shares of Common Stock of the Company
shall be issuable upon such repurchase shall be deemed to have become on the
Designated Event Payment Date the holder or holders of record of the shares
represented thereby; provided, however, that any surrender for repurchase on a
date when the stock transfer books of the Company shall be closed shall
constitute the Person or Persons in whose name or names the certificate or
certificates for such shares are to be issued as the record holder or holders
thereof for all purposes at the opening of business on the next succeeding day
on which such stock transfer books are open. No payment or adjustment shall be
made for dividends or distributions on any Common Stock of the Company issued
upon repurchase of any Security declared prior to the Designated Event Payment
Date.

        (f)   No fractions of shares shall be issued upon repurchase of
Securities. If more than one Security shall be repurchased from the same Holder
and the Purchase Price shall be payable in shares of Common Stock of the
Company, the number of full shares which shall be issuable upon such repurchase
shall be computed on the basis of the aggregate principal amount of the
Securities so repurchased. Instead of any fractional share of Common Stock of
the Company which would otherwise be issuable on the repurchase of any Security
or Securities, the Company will deliver to the applicable Holder its check for
the current market value of such fractional share or, at the Company's election,
a full share with respect to such fractional share. The current market value of
a fraction of a share is determined by multiplying the Current Market Price of a
full share on the Trading Day immediately preceding the Designated Event Payment
Date by the fraction, and rounding the result to the nearest cent.

        (g)   Any issuance and delivery of certificates for shares of Common
Stock of the Company on repurchase of Securities shall be made without charge to
the Holder of Securities being repurchased for such certificates or for any tax
or duty in respect of the issuance or delivery of such certificates or the
Securities represented thereby; provided, however, that the Company shall not be
required to pay any tax or duty which may be payable in respect of (i) income of
the Holder or (ii) any transfer involved in the issuance or delivery of
certificates for shares of Common Stock of the Company in a name other than that
of the Holder of the Securities being repurchased, and no such issuance or
delivery shall be made unless and until the Person requesting such issuance or
delivery has paid to the Company the amount of any such tax or duty or has
established, to the satisfaction of the Company, that such tax or duty has been
paid.

        (h)   The Company shall not be required to make a Designated Event Offer
upon a Change of Control if a third party makes the Designated Event Offer in
the manner, at the times and otherwise in compliance with the requirements set
forth in this Indenture applicable to a Designated Event Offer made by the
Company and purchases all Securities validly tendered and not withdrawn under
such Designated Event Offer.

        (i)   In the event that the Company makes a Designated Event Offer, the
Company shall comply with any applicable securities laws and regulations,
including any applicable requirements of Section 14(e) of, and Rule 14e-1 under,
the Exchange Act. To the extent that the provisions of any securities laws or
regulations conflict with provisions of this Section, the

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<PAGE>   84

Company shall comply with the applicable securities laws and regulations and
shall not be deemed to have breached its obligations under this Section by
virtue thereof.

SECTION 1202. Conditions to the Company's Election to Pay the Repurchase Price
in Class A Common Stock of the Company.

        The Company may elect to pay the Purchase Price by delivery of shares of
Class A Common Stock of the Company pursuant to Section 1201 if:

                (1) The shares of Class A Common Stock of the Company
        deliverable in payment of the Purchase Price shall have a fair market
        value as of the Designated Event Payment Date of not less than the
        Purchase Price. For purposes of this Section 1202, the fair market value
        of shares of Class A Common Stock of the Company shall be determined by
        the Company and shall be equal to 95% of the average of the Current
        Market Price of the Class A Common Stock of the Company for the five
        consecutive Trading Days that precede and end on and include the third
        Trading Day prior to the Designated Event Payment Date;

                (2) The shares of Class A Common Stock of the Company to be
        issued upon repurchase of Securities hereunder (i) shall not require
        registration under any federal securities law before such shares may be
        freely transferable without being subject to any transfer restrictions
        under the Securities Act upon repurchase or, if such registration is
        required, the Company shall then be in compliance with its obligation to
        register such shares of Class A Common Stock under and in accordance
        with, the terms and conditions of, the Registration Rights Agreement and
        (ii) shall not require registration with or approval of any governmental
        authority under any state law or any other federal law before such
        shares may be validly issued or delivered upon repurchase, or if such
        registration is required or such approval must be obtained, such
        registration shall be completed or such approval shall be obtained prior
        to the Designated Event Payment Date;

                (3) The shares of Class A Common Stock of the Company to be
        issued upon repurchase of Securities hereunder are, or shall have been,
        approved for listing on the NASDAQ National Market or the New York Stock
        Exchange or listed on another national securities exchange, in any case,
        prior to the Designated Event Payment Date; and

                (4) All shares of Class A Common Stock of the Company which may
        be issued upon repurchase of Securities will be issued out of the
        Company's authorized but unissued Class A Common Stock and, will upon
        issue, be duly and validly issued and fully paid and non-assessable and
        free of any preemptive or similar rights. If all of the conditions set
        forth in this Section 1202 are not satisfied in accordance with the
        terms hereof, the Purchase Price shall be paid by the Company only in
        cash.

        SECTION 1203. Consolidation, Merger, Etc.

        In the case of any consolidation, conveyance, sale, transfer or lease of
all or substantially all of the assets of the Company to which Article Eight of
the Indenture applies, in which the

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<PAGE>   85

Class A Common Stock of the Company is changed or exchanged as a result into the
right to receive shares of stock and other securities or property or assets
(including cash) which includes shares of Class A Common Stock of the Company or
common stock of another Person that are, or upon issuance will be, traded on a
United States national securities exchange or approved for trading on an
established automated over-the-counter trading market in the United States and
such shares constitute at the time such change or exchange becomes effective in
excess of 50% of the aggregate fair market value of such shares of stock and
other securities, property and assets (including cash) (as determined by the
Company, which determination shall be conclusive and binding), then the Person
formed by such consolidation or resulting from such merger or combination or
which acquires the properties or assets (including cash) of the Company, as the
case may be, shall execute and deliver to the Trustee a supplemental indenture
(which shall comply with the Trust Indenture Act as in force at the date of
execution of such supplemental indenture) modifying the provisions of this
Indenture relating to the right of Holders to cause the Company to repurchase
the Securities following a Change in Control, including without limitation the
applicable provisions of this Article Twelve and the definitions of the Class A
Common Stock and Change in Control, as appropriate, and such other related
definitions set forth herein and in the Indenture as determined in good faith by
the Company (which determination shall be conclusive and binding), to make such
provisions apply in the event of a subsequent Change of Control to the common
stock and the issuer thereof if different from the Company and Class A Common
Stock of the Company (in lieu of the Company and the Class A Common Stock of the
Company).

                               ARTICLE THIRTEEN.

                            CONVERSION OF SECURITIES

        SECTION 1301. Applicability of Article.

        Securities of any series which are convertible into Common Stock at the
option of the Holder of such Securities shall be convertible in accordance with
their terms and in accordance with this Article.

        SECTION 1302. Right of Holders to Convert Securities into Class A Common
Stock.

        Subject to and upon compliance with the terms of the Securities and the
provisions of this Article Thirteen, at the option of the Holder thereof, any
Security of any authorized denomination, or any portion of the principal amount
thereof which is $1,000 or any integral multiple of $1,000, may, at any time
prior to January 15, 2009 (except where the Company has terminated such
conversion right in accordance with Article Fourteen hereof and except that in
the case of repayment at the option of the Holder pursuant to Article Twelve
hereof, in which events such right shall terminate upon the Conversion
Termination Date or upon the Company's receipt of written notice of the exercise
of such option, as applicable), be converted into duly authorized, validly
issued, fully paid and non-assessable shares of Class A Common Stock, at the
conversion rate initially of 39.1484 shares of Class A Common Stock for each
$1,000 principal amount of Securities, or, in case an adjustment in the
conversion price has taken place pursuant

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<PAGE>   86

to the provisions of this Article Thirteen, then at the applicable conversion
rate as so adjusted (the "Conversion Rate"), upon surrender of the Security or
Securities, the principal amount of which is so to be converted, to the Company
at any time during usual business hours at the office or agency to be maintained
by it in accordance with the provisions of Section 1002, accompanied by a
written notice of election to convert as provided in Sections 203 and 1303 and,
if so required by the Company and/or the Trustee, by a written instrument or
instruments of transfer in form satisfactory to the Company and/or the Trustee,
as applicable, duly executed by the Holder thereof or his attorney duly
authorized in writing. All Securities surrendered for conversion shall, if
surrendered to the Company or any conversion agent, be delivered to the Trustee
for cancellation and cancelled by it, or shall, if surrendered to the Trustee,
be cancelled by it, as provided in Section 310.

        SECTION 1303. Issuance of Shares of Class A Common Stock on Conversions.

        As promptly as practicable after the surrender, as herein provided, of
any Security or Securities for conversion into Class A Common Stock, the Company
shall deliver or cause to be delivered at its said office or agency to or upon
the written order of the Holder of the Security or Securities so surrendered a
certificate or certificates representing the number of duly authorized, validly
issued, fully paid and nonassessable shares of Class A Common Stock into which
such Security or Securities may be converted in accordance with the terms
thereof and the provisions of this Article Thirteen. Prior to delivery of such
certificate or certificates, the Company shall require written notice at its
said office or agency from the Holder of the Security or Securities so
surrendered stating that the Holder irrevocably elects to convert such Security
or Securities, or, if less than the entire principal amount thereof is to be
converted, stating the portion thereof to be converted. Such notice shall also
state the name or names (with address and social security or other taxpayer
identification number) in which said certificate or certificates are to be
issued. Such conversion shall be deemed to have been made at the time that such
Security or Securities shall have been surrendered for conversion and such
notice shall have been received by the Company or the Trustee, the rights of the
Holder of such Security or Securities as a Holder shall cease at such time, the
Person or Persons entitled to receive the shares of Class A Common Stock upon
conversion of such Security or Securities shall be treated for all purposes as
having become either record holder or holders of such shares of Class A Common
Stock at such time and such conversion shall be at the conversion price in
effect at such time. In the case of any Security of any series which is
converted in part only, upon such conversion, the Company shall execute and,
upon the Company's request and at the Company's expense, the Trustee or an
Authenticating Agent shall authenticate and deliver to the Holder thereof, as
requested by such Holder, a new Security or Securities of such series of
authorized denominations in aggregate principal amount equal to the unconverted
portion of such Security.

        If the last day on which such Security may be converted is not a
Business Day in a place where the conversion agent is located, such Security may
be surrendered to the conversion agent on the next succeeding day that is a
Business Day.

        The Company shall not be required to deliver certificates for shares of
Class A Common Stock upon conversion while its stock transfer books are closed
for a meeting of shareholders or for the payment of dividends or for any other
purpose, but certificates for shares of Class A Common Stock shall be delivered
as soon as the stock transfer books shall again be opened.

                                       79
<PAGE>   87
        SECTION 1304. No Payment or Adjustment for Interest or Dividends.

        Securities surrendered for conversion into Class A Common Stock during
the period from the close of business on any Regular Record Date (or Special
Record Date) next preceding any Interest Payment Date to the opening of business
on such Interest Payment Date when surrendered for conversion must be
accompanied by payment (by certified or official bank check to the order of the
Company payable in clearing house funds at the location where the Securities are
surrendered) of an amount equal to the interest thereon which the Holder is
entitled to receive on such Interest Payment Date. Payment of interest shall be
made, on such Interest Payment Date, to the Holder of the Securities as of such
Regular Record Date or Special Record Date, as applicable. Except where
Securities surrendered for conversion must be accompanied by payment as
described above, no interest on converted Securities will be payable by the
Company on any Interest Payment Date subsequent to the date of conversion. No
other payment or adjustment for interest or dividends is to be made upon
conversion.

        SECTION 1305. Adjustment of Conversion Rate.

               (1) In case at any time after the date of the issuance of the
        Securities, the Company shall pay or make a dividend or other
        distribution on any class of Capital Stock of the Company payable in
        shares of Common Stock of the Company, the Conversion Rate in effect at
        the opening of business on the day following the date fixed for the
        determination of stockholders entitled to receive such dividend or other
        distribution shall be increased by dividing such Conversion Rate by a
        fraction of which the numerator shall be the number of shares of Common
        Stock of the Company outstanding at the close of business on the date
        fixed for such determination and the denominator shall be the sum of
        such number of shares and the total number of shares constituting such
        dividend or other distribution, such increase to become effective
        immediately after the opening of business on the day following the date
        fixed for such determination. For the purposes of this paragraph (1),
        the number of shares of Common Stock of the Company at any time
        outstanding shall not include shares held in the treasury of the Company
        but shall include shares issuable in respect of scrip certificates
        issued in lieu of fractions of shares of Common Stock of the Company.
        The Company will not pay any dividend or make any distribution on shares
        of Common Stock of the Company held in the treasury of the Company.

               (2) In case at any time after the date of the issuance of the
        Securities, the Company shall issue rights, options or warrants to all
        holders of its Common Stock (other than any rights, options or warrants
        that by their terms will also be issued to any Holder upon conversion of
        a Security into Common Stock of the Company without any action required
        by the Company or any other person) entitling them to subscribe for or
        purchase shares of Common Stock of the Company (or securities
        convertible into Common Stock of the Company) at a price per share (or
        having a conversion price per share) less than the Average Current
        Market Price per share (determined as provided in paragraph (9) of this
        Section) on the date fixed for the determination of stockholders
        entitled to receive such rights, options or warrants (other than
        pursuant to a dividend reinvestment plan), the Conversion Rate in effect
        at the opening of business on the day following the date fixed for such
        determination shall be increased by dividing such Conversion Rate by a
        fraction

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<PAGE>   88

        of which the numerator shall be the number of shares of Common Stock of
        the Company outstanding at the close of business on the date fixed for
        such determination plus the number of shares of Common Stock of the
        Company which the aggregate of the offering price of the total number of
        shares of Common Stock of the Company so offered (or the aggregate
        conversion price of the convertible securities so offered) for
        subscription or purchase would purchase at such Average Current Market
        Price and the denominator shall be the number of shares of Common Stock
        of the Company outstanding at the close of business on the date fixed
        for such determination plus the number of shares of Common Stock of the
        Company so offered for subscription or purchase (or into which the
        convertible securities so offered are convertible), such increase to
        become effective immediately after the opening of business on the day
        following the date fixed for such determination. For the purposes of
        this paragraph (2), the number of shares of Common Stock of the Company
        at any time outstanding shall not include shares held in the treasury of
        the Company but shall include shares issuable in respect of scrip
        certificates issued in lieu of fractions of shares of Common Stock of
        the Company. The Company will not issue any rights, options or warrants
        in respect of shares of Common Stock of the Company held in the treasury
        of the Company.

                (3) In case at any time after the date of the issuance of the
        Securities, outstanding shares of Common Stock of the Company shall be
        subdivided into a greater number of shares of Common Stock of the
        Company, the Conversion Rate in effect at the opening of business on the
        day following the day upon which such subdivision becomes effective
        shall be proportionately increased, and, conversely, in case outstanding
        shares of Common Stock of the Company shall be combined into a smaller
        number of shares of Common Stock of the Company, the Conversion Rate in
        effect at the opening of business on the day following the day upon
        which such combination becomes effective shall be proportionately
        reduced, such reduction or increase, as the case may be, to become
        effective immediately after the opening of business on the day following
        the day upon which such subdivision or combination becomes effective.

               (4) In case at any time after the date of the issuance of the
        Securities, the Company shall, by dividend or otherwise, distribute to
        all holders of its Common Stock, shares of any class of its Capital
        Stock, evidences of its indebtedness or other assets (including
        securities, but excluding any rights, options or warrants referred to in
        paragraph (2) of this Section, any dividend or distribution paid
        exclusively in cash and any dividend or distribution referred to in
        paragraph (1) of this Section), the Conversion Rate shall be adjusted so
        that the same shall equal the price determined by dividing the
        Conversion Rate in effect immediately prior to the close of business on
        the date fixed for the determination of stockholders entitled to receive
        such distribution by a fraction of which the numerator shall be the
        Average Current Market Price per share (determined as provided in
        paragraph (9) of this Section) on the date fixed for such determination
        less the then fair market value (as determined by the Board of
        Directors, whose determination shall be conclusive and described in a
        Board Resolution filed with the Trustee) of the portion of the assets,
        shares of capital stock or evidences of indebtedness so distributed
        applicable to one share of Common Stock of the Company and the
        denominator shall be such Average Current Market Price per share, such
        adjustment to become effective

                                       81
<PAGE>   89

        immediately prior to the opening of business on the day following the
        date fixed for the determination of stockholders entitled to receive
        such distribution.

                (5) In case at any time after the date of the issuance of the
        Securities, the Company shall, by dividend or otherwise, make a
        distribution to all holders of its Common Stock consisting exclusively
        of cash (excluding any cash that is distributed upon a merger or
        consolidation to which Section 1307 applies or as part of a distribution
        referred to in paragraph (4) of this Section) in an aggregate amount
        that, combined together with:

                        (A) the aggregate amount of any other distributions to
                all holders of its Common Stock made exclusively in cash within
                the 12 months preceding the date of payment of such distribution
                and in respect of which no adjustment pursuant to this paragraph
                (5) has been made, and

                        (B) the aggregate of any cash plus the fair market value
                (as determined by the Board of Directors, whose determination
                shall be conclusive and described in a Board Resolution) of
                consideration payable in respect of any tender offer by the
                Company or any of its Subsidiaries for all or any portion of the
                Common Stock of the Company concluded within the 12 months
                preceding the date of payment of such distribution and in
                respect of which no adjustment pursuant to paragraph (6) of this
                Section has been made,

        (the amount of such cash distribution together with the amounts
described in clauses (A) and (B) above being referred to herein as the
"Aggregate Cash Distribution Amount") exceeds 10% of the product of (I) the
Average Current Market Price per share on the date for the determination of
holders of shares of Common Stock of the Company entitled to receive such cash
distribution, times (II) the number of shares of Common Stock of the Company
outstanding on such date (the amount by which the Aggregate Cash Distribution
Amount exceeds 10% of the product of the amounts described in clauses (I) and
(II) above being referred to herein as the "Excess Amount"), then, and in each
such case, immediately after the close of business on such date for
determination, the Conversion Rate shall be increased in accordance with the
following formula:

                         AC =   CR / (M - (EA/O))
                                      ---------
                                     (    M     )

Where:

             AC = the adjusted Conversion Rate.

             CR = the Conversion Rate in effect immediately prior to the close
             of business on the date fixed for determination of the
             stockholders entitled to receive the distribution.

             M = the Average Current Market Price per share (determined as
             provided in paragraph (9) of this Section) on the date fixed for

                                       82
<PAGE>   90

             determination of the stockholders entitled to receive the
             distribution.

             EA = the Excess Amount.

             O = the number of shares of Common Stock of the Company
             outstanding on the date fixed for determination of the
             stockholders entitled to receive the distribution.

             (6) In case at any time after the date of the issuance of the
        Securities, a tender offer made by the Company or any Subsidiary for all
        or any portion of the Common Stock of the Company shall expire and such
        tender offer (as amended upon the expiration thereof) shall require the
        payment to stockholders (based on the acceptance (up to any maximum
        specified in the terms of the tender offer) of Purchased Shares (as
        defined below)) of an aggregate consideration having a fair market value
        (as determined by the Board of Directors, whose determination shall be
        conclusive and described in a Board Resolution) that combined together
        with:

                        (A) the aggregate of the cash plus the fair market value
             (as determined by the Board of Directors, whose determination
             shall be conclusive and described in a Board Resolution), as of
             the expiration of such tender offer, of consideration payable in
             respect of any other tender offer, by the Company or any
             Subsidiary for all or any portion of the Common Stock of the
             Company expiring within the 12 months preceding the expiration
             of such tender offer and in respect of which no adjustment
             pursuant to this paragraph (6) has been made, and

                        (B) the aggregate amount of any distributions to all
             holders of the Company's Common Stock made exclusively in cash
             within 12 months preceding the expiration of such tender offer
             and in respect of which no adjustment pursuant to paragraph (5)
             of this Section has been made,

exceeds 10% of the product of (I) the Average Current Market Price per share
(determined as provided in paragraph (9) of this Section) as of the last time
(the "Tender Expiration Time") tenders could have been made pursuant to such
tender offer (as it may be amended), times (II) the number of shares of Common
Stock of the Company outstanding (including any tendered shares) on the Tender
Expiration Time but before acceptance of shares tendered, then, and in each such
case, immediately prior to the opening of business on the day after the date of
the Tender Expiration Time, the Conversion Rate shall be increased in accordance
with the following formula:

                             AC = CR / ((M x O) - C)
                                        -----------
                                       (M x (O - TS))

Where:

               AC = the adjusted Conversion Rate.

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<PAGE>   91

               CR = the Conversion Rate immediately prior to close of business
               on the date of the Tender Expiration Time.

               M = the Average Current Market Price per share (determined as
               provided in paragraph (9) of this Section) on the date of the
               Tender Expiration Time.

               O = the number of shares of Common Stock of the Company
               outstanding (including any tendered shares) on the Tender
               Expiration Time.

               C = the amount of cash plus the fair market value (as determined
               by the Board of Directors, whose determination shall be
               conclusive and described in a Board Resolution) of the aggregate
               consideration payable to stockholders in the tender offer based
               on the acceptance (up to any maximum specified in the terms of
               the tender offer) of Purchased Shares (as defined below).

               TS = the number of all shares validly tendered and not withdrawn
               as of the Tender Expiration Time (the shares deemed so accepted
               up to any such maximum, being referred to as the "Purchased
               Shares").

                (7) In the event of a Change of Control in which both (A) the
        stockholders of the Company receive consideration per share of Class A
        Common Stock that is greater than the Conversion Price at the effective
        time of the Change of Control, without giving effect to the adjustment
        described below, and (B) at least 10% of the total consideration paid to
        the stockholders of the Company consists of cash, cash equivalents,
        securities or other assets (other than publicly traded securities)
        (collectively, "Non-Public Consideration"), then upon conversion of
        Securities after the Change of Control, in addition to the Class A
        Common Stock or other securities deliverable upon the conversion of the
        Securities as described in Section 1302 (as adjusted pursuant to
        subparagraphs (1) through (6)) above, the holder will receive a number
        of publicly traded securities of the acquiror determined through the
        following calculation:

               PV Cash Flows x (Non-Public Consideration/Total Consideration)
               --------------------------------------------------------------
                              Acquiror Stock Price

        where:

        PV Cash Flows =     the present value of the aggregate dividend
                            payments that would have been payable on the
                            Securities from the date of conversion through
                            January 15, 2004. The present value for this
                            purpose will be calculated using a discount rate
                            equal to 3.25% plus the yield to maturity of U.S.
                            Treasury securities having a maturity closest to,
                            but not later than, January 15, 2004;

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<PAGE>   92

        Total Consideration =       the total value of the consideration
                                    payable to the Company's stockholders at
                                    the effective time of such Change of
                                    Control, with the value of any assets or
                                    securities other than cash or publicly
                                    traded securities being determined in good
                                    faith by the Board of Directors based on an
                                    opinion as to such value obtained from an
                                    accounting, appraisal or investment banking
                                    firm of international standing; and

        Acquiror Stock Price =      the price per security of the acquiror's
                                    publicly traded securities delivered in
                                    connection with such Change of Control at
                                    the effective time of such Change of
                                    Control;

provided, however, that if the consideration received by the stockholders of the
Company in respect of such Change of Control consists of at least 75% Non-Public
Consideration or if the acquiror's common stock is not publicly traded, then
upon conversion of Securities after such Change of Control, in lieu of issuing
additional securities of the acquiror, as set forth in this subparagraph (7),
each Holder shall be entitled to receive an additional amount of cash calculated
as follows:

             PV Cash Flows x (Non-Public Consideration/Total Consideration)

             (8) The reclassification of Class A Common Stock of the Company
        into securities including securities other than Class A Common Stock of
        the Company (other than any reclassification upon a consolidation or
        merger to which Section 1307 applies) shall be deemed to involve (a) a
        distribution of such securities other than Class A Common Stock of the
        Company to all holders of Class A Common Stock of the Company (and the
        effective date of such reclassification shall be deemed to be "the date
        fixed for the determination of stockholders entitled to receive such
        distribution" and "the date fixed for such determination" within the
        meaning of paragraph (4) of this Section), and (b) a subdivision or
        combination, as the case may be, of the number of shares of Class A
        Common Stock of the Company outstanding immediately prior to such
        reclassification into the number of shares of Class A Common Stock of
        the Company outstanding immediately thereafter (and the effective date
        of such reclassification shall be deemed to be "the day upon which such
        subdivision becomes effective" or "the day upon which such combination
        becomes effective", as the case may be, and "the day upon which such
        subdivision or combination becomes effective" within the meaning of
        paragraph (3) of this Section).

             (9) For the purpose of any computation under paragraphs (2),
        (4), (5) and (6) of this Section, the Average Current Market Price per
        share on any date shall be deemed to be the average of the daily Current
        Market Prices for the five consecutive Trading Days selected by the
        Company commencing not more than ten Trading Days before, and ending not
        later than the earlier of, the day in question and the day before the
        "ex" date with respect to the issuance or distribution requiring such
        computation. For purposes of

                                       85
<PAGE>   93

        this paragraph, the term "ex" date, when used with respect to any
        issuance or distribution, means the first date on which the Class A
        Common Stock of the Company trades regular way in the applicable
        securities market or on the applicable securities exchange without the
        right to receive such issuance or distribution.

                (10) No adjustment in the Conversion Rate shall be required
        unless such adjustment (plus any adjustments not previously made by
        reason of this paragraph (10)) would require an increase or decrease of
        at least 1% in such price; provided, however, that any adjustments which
        by reason of this paragraph (10) are not required to be made shall be
        carried forward and taken into account in any subsequent adjustment. All
        calculations under this paragraph (10) shall be made to the nearest
        cent.

                (11) The Company may make such increases in the Conversion Rate,
        in addition to those required by this Section, as it considers to be
        advisable in order to avoid or diminish any income tax to any holders of
        shares of Common Stock of the Company resulting from any dividend or
        distribution of stock or issuance of rights or warrants to purchase or
        subscribe for stock or from any event treated as such (i) for federal
        income tax purposes or (ii) for any other reasons relating to taxes.

                (12) To the extent permitted by applicable law, the Company from
        time to time may increase the Conversion Rate by any amount for any
        period of time if the period is at least 20 days, the increase is
        irrevocable during such period, and the Board of Directors shall have
        made a determination that such increase would be in the best interests
        of the Company, which determination shall be conclusive; provided,
        however, that no such increase shall be taken into account for purposes
        of determining whether the Current Market Price for any five Trading
        Days within the period of 10 Trading Days (as determined pursuant to the
        definition of Change of Control) exceeds the Conversion Price by 105% in
        connection with an event which would otherwise be a "Change of Control"
        or whether the Current Market Price for 20 Trading Days during a period
        of 30 consecutive Trading Days exceeds the Conversion Price by 150% or
        135%, respectively, in connection with an event which would otherwise
        allow the Company to cause the conversion rights of Holders of
        Securities to expire. Whenever the Conversion Rate is increased pursuant
        to the preceding sentence, the Company shall give notice of the increase
        to the Holders in the manner provided in Section 106 at least 15 days
        prior to the date the increased Conversion Rate takes effect, and such
        notice shall state the increased Conversion Rate and the period during
        which it will be in effect.

                (13) Whenever the Conversion Rate is adjusted, as herein
        provided, the Company shall promptly file with the Trustee, at the
        Corporate Trust Office of the Trustee, and with the office or agency
        maintained by the Company for the conversion of Securities of such
        series pursuant to Section 1002, an Officers' Certificate, setting forth
        the conversion price after such adjustment and setting forth a brief
        statement of the facts requiring such adjustment, which certificate
        shall be conclusive evidence of the correctness of such adjustment.
        Neither the Trustee nor any conversion agent shall be under any duty or
        responsibility with respect to any such certificate or any facts or
        computations set forth therein, except to exhibit said certificate from
        time to time to any Holder of a Security desiring to inspect the same.
        The Company shall promptly cause a

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<PAGE>   94

        notice setting forth the adjusted conversion price to be mailed to the
        Holders of Securities, as their names and addresses appear upon the
        Security Register of the Company.

                (14) In any case in which this Section 1205 provides that an
        adjustment shall become effective immediately after a record date for an
        event, the Company may defer until the occurrence of such event (y)
        issuing to the Holder of any Security converted after such record date
        and before the occurrence of such event the additional shares of the
        Class A Common Stock of the Company issuable upon such conversion by
        reason of the adjustment required by such event over and above the Class
        A Common Stock of the Company issuable upon such conversion before
        giving effect to such adjustment and (z) paying to such Holder any
        amount in cash in lieu of any fractional share of Class A Common Stock
        of the Company pursuant to Section 1206 of the Indenture.

        SECTION 1306. No Fractional Shares to be Issued.

        No fractional shares of Common Stock shall be issued upon any conversion
of Securities. If more than one Security of any series shall be surrendered for
conversion at one time by the same Holder, the number of full shares which shall
be issuable upon conversion thereof shall be computed on the basis of the
aggregate principal amount of the Securities of such series (or specified
portions thereof to the extent permitted hereby) so surrendered. Instead of a
fraction of a share of Class A Common Stock of the Company which would otherwise
be issuable upon conversion of any Security or Securities (or specified portions
thereof), the Company shall, at its election, either (a) pay a cash adjustment
(computed to the nearest cent, with one-half cent being rounded upward) in
respect of such fraction of a share in an amount equal to the same fractional
interest of the Current Market Price of the Class A Common Stock of the Company
on the Trading Day next preceding the day of conversion or (b) round the number
of shares issuable upon conversion up to the nearest whole share.

SECTION 1307. Preservation of Conversion Rights upon Consolidation, Merger, Sale
              or Conveyance.

        In case of any consolidation of the Company with, or merger of the
Company into, any other corporation (other than a consolidation or merger in
which the Company is the continuing corporation), or in the case of any sale or
transfer of all or substantially all of the assets of the Company, the
corporation formed by such consolidation or the corporation into which the
Company shall have been merged or the corporation which shall have acquired such
assets, as the case may be, shall execute and deliver to the Trustee, a
supplemental indenture, in accordance with the provisions of Articles Eight and
Nine as they relate to supplemental indentures, providing that the Holder of
each Security then Outstanding of a series which was convertible into Class A
Common Stock shall have the right thereafter to convert such Security into the
kind and amount of shares of stock and other securities and property, including
cash, receivable upon such consolidation, merger, sale or transfer by a holder
of the number of shares of Class A Common Stock of the Company into which such
Securities might have been converted immediately prior to such consolidation,
merger, sale or transfer, assuming (i) such holder of Class A Common Stock of
the Company failed to exercise his or her rights of election, if any, as to the
kind or amount of shares of stock and other securities and property, including

                                       87
<PAGE>   95

cash, receivable upon such consolidation, merger, sale or transfer (provided
that if the kind or amount of shares of stock and other securities and property,
including cash, receivable upon such consolidation, merger, sale or transfer is
not the same for each share of Class A Common Stock of the Company held
immediately prior to such consolidation, merger, sale or transfer and in respect
of which such rights of election shall not have been exercised ("non-electing
share"), then for the purpose of this Section the kind and amount of shares of
stock and other securities and property, including cash, receivable upon such
consolidation, merger, sale or transfer by each non-electing share shall be
deemed to be the kind and amount so receivable per share by a plurality of
non-electing shares), and (ii) the Securities were convertible at the time of
such consolidation, merger, sale or transfer at the initial Conversion Rate
specified in Section 1302 hereof, as adjusted, if applicable, in accordance with
the terms of this Article Thirteen. Such supplemental indenture shall conform to
the provisions of the Trust Indenture Act as then in effect and shall provide
for adjustments which shall be as nearly equivalent as may be practicable to the
adjustments provided for in this Article Thirteen. Neither the Trustee nor any
conversion agent shall have any liability or responsibility for determining the
correctness of any provision contained in any such supplemental indenture
relating either to the kind or amount of shares of stock or other securities or
property receivable by Holders of the Securities upon the conversion of their
Securities after any such consolidation, merger, sale or transfer, or to any
adjustment to be made with respect thereto and, subject to the provisions of
Section 313 of the Trust Indenture Act, may accept as conclusive evidence of the
correctness of any such provisions, and shall be protected in relying upon, an
Officers' Certificate with respect thereto and an Opinion of Counsel with
respect to legal matters related thereto. If in the case of any such
consolidation, merger, sale or transfer, the stock or other securities and
property receivable by a Holder of the Securities includes stock or other
securities and property of a corporation other than the successor or purchasing
corporation, then such supplemental indenture shall also be executed by such
other corporation and shall contain such additional provisions to protect the
interests of the Holders of the Securities as the Board of Directors shall
reasonably consider necessary. The above provisions of this Section 1307 shall
similarly apply to successive consolidations, mergers, sales or transfers.

        SECTION 1308. Notice to Holders of the Securities Prior to Taking
Certain Types of Action.

        With respect to the Securities, in case:

        (a)   the Company shall authorize the issuance to all holders of Common
Stock of rights or warrants to subscribe for or purchase shares of its Capital
Stock or of any other right;

        (b)   the Company shall authorize the distribution to all holders of
Common Stock of evidences of indebtedness or assets (except for cash dividends
or distributions paid from retained earnings of the Company);

        (c)   of any subdivision or combination of Common Stock or of any
consolidation or merger to which the Company is a party and for which approval
by the shareholders of the Company is required, or of the sale or transfer of
all or substantially all of the assets of the Company;

                                       88
<PAGE>   96

        (d)   of the voluntary or involuntary dissolution, liquidation or
winding up of the Company;

        (e)   the Company or a Subsidiary shall take any other action that would
require an adjustment to the Conversion Rate pursuant to Section 1305 (other
than pursuant to Sections 1305(1) or 1305(3)); or

        (f)   the Company shall take any action that would require a
supplemental indenture pursuant to Section 1307;

then the Company shall cause to be filed with the Trustee and at the office or
agency maintained for the purpose of conversion of Securities of such series
pursuant to Section 1002, and shall cause to be mailed to the Holders of
Securities of such series, at their last addresses as they shall appear on the
Security Register of the Company, at least ten days prior to the applicable
record date hereinafter specified, a notice stating (i) the date as of which the
holders of Class A Common Stock to be entitled to receive any such rights,
warrants or distribution are to be determined, or (ii) the date on which any
such subdivision, combination, consolidation, merger, sale, transfer,
dissolution, liquidation, winding up or other action is expected to become
effective, and the date as of which it is expected that holders of record of
Class A Common Stock shall be entitled to exchange their Class A Common Stock
for securities or other property, if any, deliverable upon such subdivision,
combination, consolidation, merger, sale, transfer, dissolution, liquidation,
winding up or other action. The failure to give the notice required by this
Section 1308 or any defect therein shall not affect the legality or validity of
any distribution, right, warrant, subdivision, combination, consolidation,
merger, sale, transfer, dissolution, liquidation, winding up or other action, or
the vote upon any of the foregoing. Such notice shall also be published by and
at the expense of the Company not later than the aforesaid filing date at least
once in an Authorized Newspaper.

        SECTION 1309. Covenants to Reserve Shares for Issuance on Conversion of
Securities.

        The Company covenants that at all times it will reserve and keep
available out of its authorized Class A Common Stock, free from preemptive
rights, solely for the purpose of issue upon conversion of Securities as herein
provided, such number of shares of Class A Common Stock as shall then be
issuable upon the conversion of all Outstanding Securities. The Company
covenants that all shares of Class A Common Stock which shall be so issuable
shall, when issued or delivered, be duly and validly issued shares of Class A
Common Stock into which Securities of such series are convertible, and shall be
fully paid and nonassessable, free of all liens and charges and not subject to
preemptive rights and that, upon conversion, the appropriate capital stock
accounts of the Company will be duly credited.

        SECTION 1310. Compliance with Governmental Requirements.

        The Company covenants that if any shares of Class A Common Stock
required to be reserved for purposes of conversion of Securities hereunder
require registration or listing with or approval of any governmental authority
under any Federal or State law, pursuant to the Securities Act of 1933, as
amended, or the Securities Exchange Act of 1934, as amended, or any national or
regional securities exchange on which Class A Common Stock is listed at the time
of

                                       89
<PAGE>   97

delivery of any shares of Class A Common Stock, before such shares may be
issued upon conversion, the Company will use its best efforts to cause such
shares to be duly registered, listed or approved, as the case may be, and prior
to such registration shall contain the legends set forth in Section 305(d)
hereof.

        SECTION 1311. Payment of Taxes upon Certificates for Shares Issued upon
Conversion.
        The issuance of certificates for shares of Class A Common Stock upon the
conversion of Securities shall be made without charge to the converting Holders
for any tax (including, without limitation, all documentary and stamp taxes) in
respect of the issuance and delivery of such certificates, and such certificates
shall be issued in the respective names of, or in such names as may be directed
by, the holders of the Securities converted; provided, however, that the Company
shall not be required to pay any tax which may be payable in respect of any
transfer involved in the issuance and delivery of any such certificate in a name
other than that of the Holder of the Security converted, and the Company shall
not be required to issue or deliver such certificate unless or until the Person
or Persons requesting the issuance thereof shall have paid to the Company the
amount of such tax or shall have established to the satisfaction of the Company
that such tax has been paid.

        SECTION 1312. Trustee's Duties with Respect to Conversion Provisions.

        The Trustee and any conversion agent shall have no duty, responsibility
or liability to any Holder to determine whether any facts exist which may
require any adjustment of the conversion rate, or with respect to the nature or
extent of any such adjustment when made, or with respect to the method employed,
or herein or in any supplemental indenture provided to be employed, in making
the same. Neither the Trustee nor any conversion agent shall be accountable with
respect to the registration under securities laws, listing, validity or value
(or the kind or amount) of any shares of Class A Common Stock, or of any other
securities or property, which may at any time be issued or delivered upon the
conversion of any Security, and neither the Trustee nor any conversion agent
makes any representation with respect thereto. Neither the Trustee nor any
conversion agent shall be responsible for any failure of the Company to make any
cash payment or to issue, transfer or deliver any shares of stock or stock
certificates or other securities or property upon the surrender of any Security
for the purpose of conversion; and the Trustee and any conversion agent, subject
to the provisions of Section 313 of the Trust Indenture Act, shall not be
responsible for any failure of the Company to comply with any of the covenants
of the Company contained in this Article Thirteen.

                               ARTICLE FOURTEEN.

                        TERMINATION OF CONVERSION RIGHTS

        SECTION 1401. Expiration of Conversion Rights.

        On or after January 18, 2003, the Company may, at its option, terminate
the conversion rights of Holders of Securities. The Company may exercise this
option, in whole or in part, only

                                       90
<PAGE>   98

if the Current Market Price of the Class A Common Stock of the Company exceeds
150% (on or prior to January 18, 2004) or 135% (thereafter) of the Conversion
Price for at least 20 Trading Days within any period of 30 consecutive Trading
Days (the "Measurement Period"), including the last Trading Day of such period
(herein called the "Termination Condition"). The election of the Company to
terminate the conversion rights pursuant to Section 1402 shall be evidenced by a
Board Resolution.

        SECTION 1402. Election to Terminate; Press Release.

        In order to exercise its option to terminate the conversion rights of
Holders of Securities, the Company must issue a press release for publication on
the Dow Jones News Service (or a comparable news service) announcing (the date
of such notice being the "Notice Date") the date on which the conversion rights
shall terminate (the "Conversion Termination Date") prior to the opening of
business on the second Trading Day after any applicable Measurement Period. The
Conversion Termination Date shall in no event be prior to January 18, 2003 and
shall be on a date that is no less than 30 days nor more than 60 days after the
Notice Date. The press release shall announce the Conversion Termination Date
and provide the current Conversion Price of the Securities and the Current
Market Price of the Class A Common Stock of the Company, in each case as of the
close of business on the last day of the Measurement Period.

        Notice of the expiration of conversion rights will be given by the
Company to each Holder of Securities at such Holder's address in the Security
Register in accordance with Section 106 not more than four Business Days after
the Company issued the press release under Section 1402 hereof. Such notice
shall be irrevocable and shall specify the Conversion Termination Date, the
Expiration Condition pursuant to Section 1401 and whether a Make-Whole Payment
is payable.

        SECTION 1403. Conversion Expiration Date.

        Conversion rights will terminate at the close of business on the
Conversion Termination Date which will be a date selected by the Company not
less than 30 nor more than 60 days after the date on which the Company issues
the press release under Section 1402 hereof announcing its intention to
terminate conversion rights of the Securities.

        SECTION 1404. Make-Whole Payment.

        If the Conversion Termination Date occurs on or before January 18, 2004,
the Company shall make an additional payment in cash (herein call the
"Make-Whole Payment") with respect to the Securities converted into Class A
Common Stock of the company after the Notice Date. The Make-Whole Payment will
be equal to the present value of the aggregate value of the interest payments
that would thereafter have been payable on the Securities on each semi-annual
interest payment date from the Conversion Termination Date through January 15,
2009. The present value will be calculated using the bond equivalent yield on
U.S. Treasury notes or bills having a term nearest in length to that of the
additional period as of the day immediately preceding the Conversion Termination
Date.

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<PAGE>   99

        SECTION 1405. Deposit of Make Whole Payment.

        Not less than one Business Day prior to any Conversion Termination Date,
the Company shall deposit with the Trustee an amount of money (which shall be in
immediately available funds on such Conversion Termination Date) sufficient to
make the Make-Whole Payment of, and (except if the Conversion Termination Date
shall be an Interest Payment Date) accrued interest on all the Securities other
than any Securities which have been converted prior to the date of such deposit.

        If any Security with respect to which the conversion right has been
terminated is converted, any money deposited with the Trustee or so segregated
and held in trust for the Make-Whole Payment shall (subject to any right of the
Holder of such Security or any predecessor Security to receive interest) be paid
to the Company on the Company's request or, if then held by the Company, shall
be discharged from such trust.

                                ARTICLE FIFTEEN.

                          SUBORDINATION OF SECURITIES

        SECTION 1501. Securities Subordinated to Senior Indebtedness.

        The Company and each Holder, by its acceptance of Securities, agree that
(a) the payment of the principal of, interest on, or Liquidated Damages, if any,
with respect to, the Securities and (b) any other payment in respect of the
Securities, including on account of the acquisition or purchase of the
Securities by the Company (including, without limitation, pursuant to Article
Twelve) are subordinated, to the extent and in the manner provided in this
Article Fifteen, to the prior payment in full of all Senior Indebtedness of the
Company, whether outstanding at the date of this Indenture or thereafter
created, incurred, assumed or guaranteed, and that these subordination
provisions are for the benefit of the holders of Senior Indebtedness.

        This Article Fifteen shall constitute a continuing offer to all Persons
who, in reliance upon such provisions, become holders of, or continue to hold,
Senior Indebtedness, and such provisions are made for the benefit of the holders
of Senior Indebtedness, and such holders are made obligees hereunder and any one
or more of them may enforce such provisions.

        SECTION 1502. No Payment on Securities in Certain Circumstances.

        (a)   No payment may be made by the Company on account of the principal
of, interest on, or Liquidated Damages, if any, with respect to, the Securities,
or to acquire any of the Securities (including repurchases of Securities at the
option of the Holder pursuant to a Designated Event Offer) for cash or property
(other than pursuant to the conversion of Securities), or on account of the
redemption provisions of the Securities, in the event of default in the payment
of any principal of, premium, if any, or interest on any Senior Indebtedness of
the Company when it becomes due and payable, whether at maturity or at a date
fixed for prepayment or by declaration or otherwise (a "Payment Default"),
unless and until such Payment Default has been cured or waived or otherwise has
ceased to exist.

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<PAGE>   100

        (b)   Upon (i) the happening of an event of default (other than a
Payment Default) that permits, or would permit, with (w) the passage of time,
(x) the giving of notice, (y) the making of any payment in respect of the
Securities then required to be made, or (z) any combination thereof
(collectively, a "Non-Payment Default"), the holders of Designated Senior
Indebtedness or their representative immediately to accelerate the maturity of
any Designated Senior Indebtedness and (ii) written notice of such Non-Payment
Default is given to the Company and the Trustee by the holders of Designated
Senior Indebtedness or their representative, or to the Trustee and the holders
of Designated Senior Indebtedness by the Company or its Representative (a
"Payment Blockage Notice"), then, unless and until such Non-Payment Default has
been cured or waived or otherwise has ceased to exist, no payment (by setoff or
otherwise) may be made by or on behalf of the Company on account of the
principal of, interest on, or Liquidated Damages, if any, with respect to, the
Securities, or to acquire or repurchase any of the Securities for cash or
property, or on account of the redemption provisions of the Securities, in any
such case other than payments made upon conversion of the Securities and other
than payments made with Junior Securities.

        Notwithstanding the foregoing, unless (i) the Designated Senior
Indebtedness in respect of which such Non-Payment Default exists has been
declared due and payable in its entirety within 179 days after the Payment
Blockage Notice is delivered as set forth above (the "Payment Blockage Period"),
and (ii) such declaration has not been rescinded or waived, at the end of the
Payment Blockage Period, the Company shall be required to pay all sums not paid
to the Holders of the Securities during the Payment Blockage Period due to the
foregoing prohibitions and to resume all other payments as and when due on the
Securities. Not more than one Payment Blockage Notice may be given in any
365-day period, irrespective of the number of defaults with respect to
Designated Senior Indebtedness during such period. In no event, however, may the
total number of days during which any Payment Blockage Period or Payment
Blockage Periods are in effect exceed 179 days in the aggregate during any
consecutive 365-day period.

        (c)   In furtherance of the provisions of Section 1501, in the event
that, notwithstanding the foregoing provisions of this Section 1502, any payment
or distribution of assets of the Company (other than pursuant to the conversion
of the Securities) shall be received by the Trustee or the Holders at a time
when such payment or distribution is prohibited by the provisions of this
Section 1502, then such payment or distribution (subject to the provisions of
Section 1507) shall be received and held in trust by the Trustee or such Holder
for the benefit of the holders of Senior Indebtedness of the Company, and shall
be paid or delivered by the Trustee or such Holders, as the case may be, to the
holders of Senior Indebtedness of the Company remaining unpaid or unprovided for
or their representative or representatives, or to the trustee or trustees under
any indenture pursuant to which any instruments evidencing any of such Senior
Indebtedness of the Company may have been issued, ratably according to the
aggregate amounts remaining unpaid on account of the Senior Indebtedness of the
Company held or represented by each, for application to the payment of all
Senior Indebtedness of the Company remaining unpaid, to the extent necessary to
pay or provide for the payment of all such Senior Indebtedness in full after
giving effect to any concurrent payment or distribution of, or provision
therefor, to the holders of such Senior Indebtedness.

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<PAGE>   101

SECTION 1503. Securities Subordinated to Prior Payment of All Senior
              Indebtedness on Dissolution, Liquidation or Reorganization.

        Upon any distribution of assets of the Company upon any dissolution,
winding up, total or partial liquidation or reorganization of the Company,
whether voluntary or involuntary, in bankruptcy, insolvency, receivership or a
similar proceeding or upon assignment for the benefit of creditors or any
marshalling of assets or liabilities:

        (a)   the holders of all Senior Indebtedness of the Company shall first
be entitled to receive payments in full in cash or other payment satisfactory to
the holders of Senior Indebtedness (or have such payment duly provided for)
before the Holders are entitled to receive any payment on account of the
principal of, premium, if any, interest on, or Liquidated Damages, if any, with
respect to, the Securities (other than payments made in the form of Junior
Securities);

        (b)   any payment or distribution of assets of the Company of any kind
or character, whether in cash, property or securities (other than payments or
distributions in the form of Junior Securities) to which the Holders or the
Trustee on behalf of the Holders would be entitled (by setoff or otherwise),
except for the provisions of this Article Fifteen, shall be paid by the
liquidating trustee or agent or other Person making such a payment or
distribution directly to the holders of Senior Indebtedness of the Company or
their representative to the extent necessary to make payment in full in cash or
other payment satisfactory to the holders of Senior Debt of all such Senior
Indebtedness remaining unpaid, after giving effect to any concurrent payment or
distribution to the holders of such Senior Indebtedness; and

        (c)   in the event that, notwithstanding the foregoing, any payment or
distribution of assets of the Company of any kind or character, whether in cash,
property or securities (other than payments or distributions in the form of
Junior Securities), shall be received by the Trustee or the Holders or any
Paying Agent (or, if the Company or an Affiliate of the Company is acting as its
own Paying Agent, money for any such payment or distribution shall be segregated
or held in trust) on account of the Securities before all Senior Indebtedness of
the Company is paid in full, such payment or distribution (subject to the
provisions of Section 1507) shall be received and held in trust by the Trustee
or such Holder or Paying Agent for the benefit of the holders of such Senior
Indebtedness, or their respective representative, ratably according to the
respective amounts of such Senior Indebtedness held or represented by each, to
the extent necessary to make payments as provided herein of all such Senior
Indebtedness remaining unpaid after giving effect to all concurrent payments and
distributions and all provisions therefor to or for the holders of such Senior
Indebtedness, but only to the extent that as to any holder of such Senior
Indebtedness, as promptly as practical following notice from the Trustee to the
holders of such Senior Indebtedness that such prohibited payment has been
received by the Trustee, Holder(s) or Paying Agent (or has been segregated as
provided above), such holder (or a representative therefor) notifies the Trustee
of the amounts then due and owing on such Senior Indebtedness, if any, held by
such holder and only the amounts specified in such notices to the Trustee shall
be paid to the holders of such Senior Indebtedness.

                                       94
<PAGE>   102

        SECTION 1504. Securityholders to Be Subrogated to Rights of Holders of
Senior Indebtedness.

        Subject to the payment in full of all Senior Indebtedness of the Company
as provided herein, the Holders of Securities shall be subrogated to the rights
of the holders of such Senior Indebtedness to receive payments or distributions
of assets of the Company applicable to the Senior Indebtedness until all amounts
owing on the Securities shall be paid in full, and for the purpose of such
subrogation no such payments or distributions to the holders of such Senior
Indebtedness by the Company, or by or on behalf of the Holders by virtue of this
Article Fifteen, which otherwise would have been made to the Holders shall, as
between the Company and the Holders, be deemed to be payment by the Company or
on account of such Senior Indebtedness, it being understood that the provisions
of this Article Fifteen are and are intended solely for the purpose of defining
the relative rights of the Holders, on the one hand, and the holders of such
Senior Indebtedness, on the other hand.

        If any payment or distribution to which the Holders would otherwise have
been entitled but for the provisions of this Article Fifteen shall have been
applied, pursuant to the provisions of this Article Fifteen, to the payment of
amounts payable under Senior Indebtedness of the Company, then the Holders shall
be entitled to receive from the holders of such Senior Indebtedness any payments
or distributions received by such holders of Senior Indebtedness in excess of
the amount sufficient to pay all amounts payable under or in respect of such
Senior Indebtedness in full.

        SECTION 1505. Obligations of the Company Unconditional.

        Nothing contained in this Article Fifteen or elsewhere in this Indenture
or in the Securities is intended to or shall impair as between the Company and
the Holders, the obligation of the Company, which is absolute and unconditional,
to pay to the Holders the principal, Redemption Price and Repurchase Price of,
and interest and any Liquidated Damages on, the Securities as and when the same
shall become due and payable in accordance with their terms, or is intended to
or shall affect the relative rights of the Holders and creditors of the Company
other than the holders of the Senior Indebtedness, nor shall anything herein or
therein prevent the Trustee or any Holder from exercising all remedies otherwise
permitted by applicable law upon default under this Indenture, subject to the
rights, if any, under this Article Fifteen, of the holders of Senior
Indebtedness in respect of cash, property or securities of the Company received
upon the exercise of any such remedy.

        Notwithstanding anything to the contrary in this Article Fifteen or
elsewhere in this Indenture or in the Securities, upon any distribution of
assets of the Company referred to in this Article Fifteen, the Trustee, subject
to the provisions of Sections 601 and 603, and the Holders shall be entitled to
rely upon any order or decree made by any court of competent jurisdiction in
which such dissolution, winding up, liquidation or reorganization proceedings
are pending, or a certificate of the liquidating trustee or agent or other
Person making any distribution to the Trustee or to the Holders for the purpose
of ascertaining the Persons entitled to participate in such distribution, the
holders of the Senior Indebtedness and other Indebtedness of the Company, the
amount thereof or payable thereon, the amount or amounts paid or distributed
thereon and all other facts pertinent thereto or to this Article Fifteen so long
as such court has been apprised of

                                       95
<PAGE>   103

the provisions of, or the order, decree or certificate makes reference to, the
provisions of this Article Fifteen. Nothing in this Article Fifteen shall apply
to the claims of, or payments to, the Trustee under or pursuant to Sections 506
and 607.

        SECTION 1506. Trustee Entitled To Assume Payments Not Prohibited in
Absence of Notice.

        The Trustee or any Paying Agent shall not at any time be charged with
knowledge of the existence of any facts which would prohibit the making of any
payment to or by the Trustee or any Paying Agent unless and until a Trust
Officer of the Trustee or any Paying Agent shall have received, no later than
one Business Day prior to such payment, written notice thereof from the Company
or from one or more holders of Senior Indebtedness or from any representative
therefor and, prior to the receipt of any such written notice, the Trustee,
subject to the provisions of Sections 601 and 603, shall be entitled in all
respects conclusively to assume that no such fact exists.

        SECTION 1507. Application by Trustee of Assets Deposited with It.

        Amounts deposited in trust with the Trustee pursuant to and in
accordance with this Indenture shall be for the sole benefit of Holders of
Securities and, to the extent allocated for the payment of Securities, shall not
be subject to the subordination provisions of this Article Fifteen. Otherwise,
any deposit of assets with the Trustee or the Agent (whether or not in trust)
for the payment of any Securities shall be subject to the provisions of Sections
1501, 1502, 1503 and 1504; provided that, if prior to one Business Day preceding
the date on which by the terms of this Indenture any such assets may become
distributable for any purpose (including, without limitation, the payment of any
amount due on any Security) and the Trustee or such Paying Agent shall not have
received with respect to such assets the written notice provided for in Section
1506, then the Trustee or such Paying Agent shall have full power and authority
to receive such assets and to apply the same to the purpose for which they were
received, and shall not be affected by any notice to the contrary which may be
received by it on or after such date.

SECTION 1508. Subordination Rights Not Impaired by Acts or Omissions of the
              Company or Holders of Senior Indebtedness.

        No right of any present or future holders of any Senior Indebtedness to
enforce subordination provisions contained in this Article Fifteen shall at any
time in any way be prejudiced or impaired by any act or failure to act on the
part of the Company or by any act or failure to act, in good faith, by any such
holder, or by any noncompliance by the Company with the terms of this Indenture,
regardless of any knowledge thereof which any such holder may have or be
otherwise charged with. The holders of Senior Indebtedness may extend, renew,
modify or amend the terms of the Senior Indebtedness or any security therefor
and release, sell or exchange such security and otherwise deal freely with the
Company, all without affecting the liabilities and obligations of the parties to
this Indenture or the Holders.

                                       96
<PAGE>   104

        SECTION 1509. Securityholders Authorize Trustee to Effectuate
Subordination of Securities.

        Each Holder of the Securities by his acceptance thereof authorizes and
expressly directs the Trustee on his behalf to take such action as may be
necessary or appropriate to effectuate the subordination provisions contained in
this Article Fifteen and to protect the rights of the Holders pursuant to this
Indenture, and appoints the Trustee his attorney-in-fact for such purpose,
including, in the event of any dissolution, winding up, liquidation or
reorganization of the Company (whether in bankruptcy, insolvency or receivership
proceedings or upon an assignment for the benefit of creditors of the Company),
the immediate filing of a claim for the unpaid balance of his Securities in the
form required in said proceedings and cause said claim to be approved. If the
Trustee does not file a proper claim or proof of debt in the form required in
such proceeding prior to 30 days before the expiration of the time to file such
claim or claims, then the holders of the Senior Indebtedness or their
representative are or is hereby authorized to have the right to file and are or
is hereby authorized to file an appropriate claim for and on behalf of the
Holders of said Securities. Nothing herein contained shall be deemed to
authorize the Trustee or the holders of Senior Indebtedness or their
representative to authorize or consent to or accept or adopt on behalf of any
Securityholder any plan of reorganization, arrangement, adjustment or
composition affecting the Securities or the rights of any Holder thereof, or to
authorize the Trustee or the holders of Senior Indebtedness or their
representative to vote in respect of the claim of any Securityholder in any such
proceeding.

        SECTION 1510. Right of Trustee to Hold Senior Indebtedness.

        The Trustee shall be entitled to all of the rights set forth in this
Article Fifteen in respect of any Senior Indebtedness at any time held by it to
the same extent as any other holder of Senior Indebtedness, and nothing in this
Indenture shall be construed to deprive the Trustee of any of its rights as such
holder.

        SECTION 1511. Article Fifteen Not to Prevent Events of Default.

        The failure to make any payment due on the Securities by reason of any
provision of this Article Fifteen shall not be construed as preventing the
occurrence of a Default or an Event of Default under Section 601 or in any way
prevent the Holders from exercising any right hereunder other than the right to
receive payment on the Securities.

        SECTION 1512. No Fiduciary Duty of Trustee to Holders of Senior
Indebtedness.

        The Trustee shall not be deemed to owe any fiduciary duty to the holders
of Senior Indebtedness, and shall not be liable to any such holders (other than
for its willful misconduct or negligence) if it shall in good faith mistakenly
pay over or distribute to the Holders of Securities or the Company or any other
Person, cash, property or securities to which any holders of Senior Indebtedness
shall be entitled by virtue of this Article Fifteen or otherwise. With respect
to the holders of Senior Indebtedness, the Trustee undertakes to perform or
observe only such of its covenants or obligations as are specifically set forth
in this Article and no implied covenants or obligations with respect holders of
Senior Indebtedness shall be read into this Indenture against the Trustee.
Nothing in this Section 1512 shall affect the obligation of any other such
Person to

                                       97
<PAGE>   105

hold such payment for the benefit of, and to pay such payment over to, the
holders of Senior Indebtedness or their representative.

                                    * * * * *

        This 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 Indenture.

                                       98
<PAGE>   106

        IN WITNESS WHEREOF, the parties hereto have caused this Indenture to be
duly executed.

                                    XO COMMUNICATIONS, INC.

                                    By: s/Wayne M. Rehberger
                                        ----------------------------
                                         Name:  Wayne M. Rehberger
                                         Title: Senior Vice President and Chief
                                                Financial Officer

Attest: s/Gary D. Begeman
        -------------------------------
        Name: Gary D. Begeman
        Title:  Senior Vice President,
               General Counsel and Secretary

                                    U.S. TRUST COMPANY, NATIONAL
                                      ASSOCIATION, as Trustee

                                    By: s/Patricia Gallagher
                                        ------------------------------
                                        Name: Patricia Gallagher
                                        Title:  Authorized Signatory

Attest: s/Cynthia Chaney
        -------------------------------
        Name: Cynthia Chaney
        Title:  Authorized Signatory

                                       99
<PAGE>   107

COMMON WEALTH OF VIRGINIA)
                         ) ss:
COUNTY OF FAIRFAX        )

        On this 12th day of January, 2001, before me personally came Wayne M.
Rehberger, to me known, who, being by me duly sworn, did depose and say that he
resides at Reston, Virginia that he is Senior Vice President, Chief Financial
Officer of XO Communications, Inc., one of the corporations described in and
which executed the foregoing instrument; and duly acknowledged to me that he
executed the same by authority of the Board of Directors of said corporation.

        IN TESTIMONY WHEREOF, I have hereunto set my hand and affixed my
official seal in the County and State aforesaid on the day and year first
written above

[Notarial Seal]

                                            s/ Catheryn O. Lowe
                                            ------------------------------------
                                            Notary Public

                                      100
<PAGE>   108

STATE OF NEW YORK  )
                   ) ss:
COUNTY OF NEW YORK )

        On the 12th day of January, 2001, before me personally came Patricia
Gallagher, to me known, who, being by me duly sworn, did depose and say that she
resides at _____, New York, that she is an Authorized Signatory of U.S. Trust
Company, National Association, one of the corporations described in and which
executed the foregoing instrument, and that she executed the same by authority
of the Board of Directors of said corporation.

[Notarial Seal]

                                  s/ Christine C. Collins
                                  --------------------------------------------
                                  Notary Public

                                  COMMISSION EXPIRES

                                      101
<PAGE>   109

                                                              ANNEX A -- Form of
                                                        Regulation S Certificate

                            REGULATION S CERTIFICATE

  (For transfers pursuant to Section 305(b)(i), (iii) and (v) of the Indenture)

U.S. Trust Company, National Association,
  as Trustee
c/o United States Trust Company of New York
114 West 47th Street, 25th Floor
New York, New York  10036
Attention:  Corporate Trust Trustee Administration

        Re:   5 3/4% Convertible Subordinated Notes due 2009
              of XO Communications, Inc.
              (the "Securities")

        Reference is made to the Indenture, dated as of January 12, 2001 (the
"Indenture"), between XO Communications, Inc. (the "Company") and U.S. Trust
Company, National Association, as Trustee. Terms used herein and defined in the
Indenture or in Regulation S or Rule 144 under the U.S. Securities Act of 1933,
as amended (the "Securities Act") are used herein as so defined.

        This certificate relates to U.S. $____________ principal amount of
Securities, which are evidenced by the following certificate(s) (the "Specified
Securities"):

        CUSIP No(s). ___________________________

        CERTIFICATE No(s). _____________________

The person in whose name this certificate is executed below (the "Undersigned")
hereby certifies that either (i) it is the sole beneficial owner of the
Specified Securities or (ii) it is acting on behalf of all the beneficial owners
of the Specified Securities and is duly authorized by them to do so. Such
beneficial owner or owners are referred to herein collectively as the "Owner".
If the Specified Securities are represented by a Global Security, they are held
through the Depositary or an Agent Member in the name of the Undersigned, as or
on behalf of the Owner. If the Specified Securities are not represented by a
Global Security, they are registered in the name of the Undersigned, as or on
behalf of the Owner.

        The Owner has requested that the Specified Securities be transferred to
a person (the "Transferee") who will take delivery in the form of a Regulation S
Security. In connection with such transfer, the Owner hereby certifies that,
unless such transfer is being effected pursuant to an effective registration
statement under the Securities Act, it is being effected in accordance with Rule
904 or Rule 144 under the Securities Act and with all applicable securities laws
of the states of the United States and other jurisdictions. Accordingly, the
Owner hereby further certifies as follows:

                                       1
<PAGE>   110

                (1) Rule 904 Transfers. If the transfer is being effected in
        accordance with Rule 904:

                        (A) the Owner is not a distributor of the Securities, an
                affiliate of the Company or any such distributor or a person
                acting on behalf of any of the foregoing;

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

                        (C) either:

                                        (i) at the time the buy order was
                                originated, the Transferee was outside the
                                United States or the Owner and any person acting
                                on its behalf reasonably believed that the
                                Transferee was outside the United States, or

                                        (ii) the transaction is being executed
                                in, on or through the facilities of the Eurobond
                                market, as regulated by the Association of
                                International Bond Dealers, or another
                                designated offshore securities market and
                                neither the Owner nor any person acting on its
                                behalf knows that the transaction has been
                                prearranged with a buyer in the United States;

                        (D) no directed selling efforts have been made in the
                United States by or on behalf of the Owner or any affiliate
                thereof;

                        (E) if the Owner is a dealer in securities or has
                received a selling concession, fee or other remuneration in
                respect of the Specified Securities, and the transfer is to
                occur during the Restricted Period, then the requirements of
                Rule 904(c)(1) have been satisfied; and

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

                (2) Rule 144 Transfers. If the transfer is being effected
        pursuant to Rule 144:

                        (A) the transfer is occurring after a holding period of
                at least one year (computed in accordance with paragraph (d) of
                Rule 144) has elapsed since the Specified Securities were last
                acquired from the Company or from an affiliate of the Company,
                whichever is later, and is being effected in accordance with the
                applicable amount, manner of sale and notice requirements of
                Rule 144; or

                        (B) the transfer is occurring after a holding period of
                at least two years has elapsed since the Specified Securities
                were last acquired from the Company or from an affiliate of the
                Company, whichever is later, and the Owner is not, and during
                the preceding three months has not been, an affiliate of the
                Company.

                                       2
<PAGE>   111

        This certificate and the statements contained herein are made for your
benefit and the benefit of the Company and the Purchasers.

Dated:
                ----------------------------------------------------------
                      (Print the name of the Undersigned,
                      as such term is defined in the
                      second paragraph of this certificate.)

                      By:
                         ----------------------------------------------------
                         Name:
                         Title:
                      (If the Undersigned is a corporation, partnership or
                      fiduciary, the title of the person signing on behalf of
                      the Undersigned must be stated.)

                                       3
<PAGE>   112

                                                   ANNEX B -- Form of Restricted
                                                          Securities Certificate

                        RESTRICTED SECURITIES CERTIFICATE

       (For transfers pursuant to Section 305(b)(ii), (iii), (iv) and (v)
                               of the Indenture)

U.S. Trust Company, National Association,
  as Trustee
c/o United States Trust Company of New York
114 West 47th Street, 25th Floor
New York, New York 10036
Attention:  Corporate Trust Trustee Administration

        Re:   5 3/4% Convertible Subordinated Notes due 2009
              of XO Communications, Inc. (the "Securities")

        Reference is made to the Indenture, dated as of January 12, 2001 (the
"Indenture"), between XO Communications Inc. (the "Company") and U.S. Trust
Company, National Association, as Trustee. Terms used herein and defined in the
Indenture or in Regulation S or Rule 144 under the U.S. Securities Act of 1933,
as amended (the "Securities Act") are used herein as so defined.

        This certificate relates to U.S. $_____________ principal amount of
Securities, which are evidenced by the following certificate(s) (the "Specified
Securities"):

        CUSIP No(s). ___________________________

        CERTIFICATE No(s). _____________________

        The person in whose name this certificate is executed below (the
"Undersigned") hereby certifies that either (i) it is the sole beneficial owner
of the Specified Securities or (ii) it is acting on behalf of all the beneficial
owners of the Specified Securities and is duly authorized by them to do so. Such
beneficial owner or owners are referred to herein collectively as the "Owner".
If the Specified Securities are represented by a Global Security, they are held
through the Depositary or an Agent Member in the name of the Undersigned, as or
on behalf of the Owner. If the Specified Securities are not represented by a
Global Security, they are registered in the name of the Undersigned, as or on
behalf of the Owner.

        The Owner has requested that the Specified Securities be transferred to
a person (the "Transferee") who will take delivery in the form of a Restricted
Security. In connection with such transfer, the Owner hereby certifies that,
unless such transfer is being effected pursuant to an effective registration
statement under the Securities Act, it is being effected in accordance with Rule
144A or Rule 144 under the Securities Act and all applicable securities laws of
the states of the United States and other jurisdictions. Accordingly, the Owner
hereby further certifies as follows:

                                       1
<PAGE>   113

                (1) Rule 144A Transfers. If the transfer is being effected in
        accordance with Rule 144A:

                        (A) the Specified Securities are being transferred to a
                person that the Owner and any person acting on its behalf
                reasonably believe is a "qualified institutional buyer" within
                the meaning of Rule 144A, acquiring for its own account or for
                the account of a qualified institutional buyer; and

                        (B) the Owner and any person acting on its behalf have
                taken reasonable steps to ensure that the Transferee is aware
                that the Owner may be relying on Rule 144A in connection with
                the transfer; and

                (2) Rule 144 Transfers. If the transfer is being effected
        pursuant to Rule 144:

                        (A) the transfer is occurring after a holding period of
                at least one year (computed in accordance with paragraph (d) of
                Rule 144) has elapsed since the Specified Securities were last
                acquired from the Company or from an affiliate of the Company,
                whichever is later, and is being effected in accordance with the
                applicable amount, manner of sale and notice requirements of
                Rule 144; or

                        (B) the transfer is occurring after a holding period of
                at least two years has elapsed since the Specified Securities
                were last acquired from the Company or from an affiliate of the
                Company, whichever is later, and the Owner is not, and during
                the preceding three months has not been, an affiliate of the
                Company.

        This certificate and the statements contained herein are made for your
benefit and the benefit of the Company and the Purchasers.

Dated:
            ----------------------------------------------------------
                  (Print the name of the Undersigned,
                  as such term is defined in the
                  second paragraph of this certificate.)

                  By:
                     -----------------------------------------------
                     Name:
                     Title:
                  (If the Undersigned is a corporation, partnership or
                  fiduciary, the title of the person signing on behalf of
                  the Undersigned must be stated.)

                                                 ANNEX C -- Form of Unrestricted
                                                          Securities Certificate

                                       2
<PAGE>   114

                       UNRESTRICTED SECURITIES CERTIFICATE

       (For removal of Securities Act Legends pursuant to Section 305(c))

U.S. Trust Company, National Association,
  as Trustee
c/o United States Trust Company of New York
114 West 47th Street, 25th Floor
New York, New York 10036
Attention:  Corporate Trust Trustee Administration

        Re:    5 3/4% Convertible Subordinated Notes due 2009
               of XO Communications, Inc. (the "Securities")

        Reference is made to the Indenture, dated as of January 12, 2001 (the
"Indenture"), between XO Communications, Inc. (the "Company") and U.S. Trust
Company of Texas, as Trustee. Terms used herein and defined in the Indenture or
in Regulation S or Rule 144 under the U.S. Securities Act of 1933, as amended
(the "Securities Act") are used herein as so defined.

        This certificate relates to U.S. $_____________ principal amount of
Securities, which are evidenced by the following certificate(s) (the "Specified
Securities"):

        CUSIP No(s). ___________________________

        CERTIFICATE No(s). _____________________

The person in whose name this certificate is executed below (the "Undersigned")
hereby certifies that either (i) it is the sole beneficial owner of the
Specified Securities or (ii) it is acting on behalf of all the beneficial owners
of the Specified Securities and is duly authorized by them to do so. Such
beneficial owner or owners are referred to herein collectively as the "Owner".
If the Specified Securities are represented by a Global Security, they are held
through the Depositary or an Agent Member in the name of the Undersigned, as or
on behalf of the Owner. If the Specified Securities are not represented by a
Global Security, they are registered in the name of the Undersigned, as or on
behalf of the Owner.

        The Owner has requested that the Specified Securities be exchanged for
Securities bearing no Securities Act Legend pursuant to Section 305(c) of the
Indenture. In connection with such exchange, the Owner hereby certifies that the
exchange is occurring after a holding period of at least two years (computed in
accordance with paragraph (d) of Rule 144) has elapsed since the Specified
Securities were last acquired from the Company or from an affiliate of the
Company, whichever is later, and the Owner is not, and during the preceding
three months has not been, an affiliate of the Company. The Owner also
acknowledges that any future transfers of the Specified Securities must comply
with all applicable securities laws of the states of the United States and other
jurisdictions.

        This certificate and the statements contained herein are made for your
benefit and the benefit of the Company and the Purchasers.

                                       2
<PAGE>   115

Dated:
           ----------------------------------------------------------
               (Print the name of the Undersigned,
               as such term is defined in the
               second paragraph of this certificate.)

               By:
                  -----------------------------------------------
                  Name:
                  Title:
               (If the Undersigned is a corporation, partnership or
               fiduciary, the title of the person signing on behalf of
               the Undersigned must be stated.)

                                       3
<PAGE>   116

<TABLE>

<S>                                       <C>                                              <C>
Act........................................2      Interest Payment Date.....................10
Affiliate..................................2      Junior Securities.........................10
Agent Member...............................2      Liquidated Damages........................10
Applicable Procedures......................2      Material Subsidiary.......................10
Authenticating Agent.......................2      Maturity..................................10
Authorized Newspaper.......................2      Measurement Period........................10
Board of Directors.........................2      Obligations...............................10
Board Resolution...........................2      Officers' Certificate.....................10
Business Day...............................2      Opinion of Counsel........................10
Capital Lease Obligation...................3      Outstanding...............................10
Capital Stock..............................3      Paying Agent..............................11
Cedel......................................3      Payment Blockage Notice...................11
Change of Control..........................3      Person....................................11
Class A Common Stock.......................4      Predecessor Security......................11
Class B Common Stock.......................4      Preferred Stock...........................12
Commission.................................4      Purchase Agreement........................12
Common Stock...............................4      Purchase Price............................12
Company....................................4      Registered Securities.....................12
Company Order..............................4      Registration Default......................12
Company Request............................4      Registration Rights Agreement.............12
Conversion Price...........................4      Regular Record Date.......................12
Conversion Rate............................4      Regulation S..............................12
Conversion Termination Date................4      Regulation S Certificate..................12
Corporate Trust Office.....................4      Regulation S Global Security..............12
corporation................................4      Regulation S Legend.......................12
Credit Agreement...........................4      Regulation S Securities...................12
Current Market Price.......................4      Restricted Global Security................12
Default....................................5      Restricted Period.........................12
Defaulted Interest.........................5      Restricted Securities.....................13
Depositary.................................5      Restricted Securities Certificate.........13
Designated Event...........................5      Restricted Securities Legend..............13
Designated Event Offer.....................5      Rule 144A.................................13
Designated Event Payment Date..............7      Rule 144A Securities......................13
Designated Senior Indebtedness.............7      SEC Reports...............................13
DTC........................................8      Securities................................13
Eagle River................................8      Securities Act............................13
Euroclear..................................8      Securities Act Legend.....................13
Event of Default...........................8      Security Register.........................13
Exchange Act...............................8      Security Registrar........................13
Expiration Date............................8      Senior Indebtedness.......................13
Global Security............................8      Special Record Date.......................14
Guarantee..................................8      Stated Maturity...........................14
Holder.....................................8      Step-Down Date............................14
Incur......................................8      Step-Up...................................14
Indebtedness...............................9      Subsequent Step-Down Date.................14
Indenture..................................9      Subsequent Step-Up........................14
</TABLE>

                                       1

<PAGE>   117
<TABLE>
<S>                                      <C>                                               <C>
Subsidiary................................14      Trust Indenture Act.......................15
Successor Security........................14      Trustee...................................15
Suspension Period.........................14      Unrestricted Securities Certificate.......15
Termination Condition.....................14      Vice President............................15
Termination of Trading....................14      Voting Stock..............................15
Trading Day...............................15      Waiver....................................15
</TABLE>

                                       2

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