<PAGE>   1
                                                                   EXHIBIT 10.10



11/09/00






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


                                 LEASE AGREEMENT


                                 BY AND BETWEEN


                          DESTA FIVE PARTNERSHIP, LTD.


                                  AS LANDLORD,


                                       and


                               CIRRUS LOGIC, INC.


                                    AS TENANT

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



                                       1
<PAGE>   2




                                TABLE OF CONTENTS
<TABLE>
<S>                                                                                                              <C>
ARTICLE I -
LEASED PREMISES...................................................................................................8

Section 1.01      Leased Premises.................................................................................8

Section 1.02      Lease Grant.....................................................................................9

Section 1.03      Building Core and Shell.........................................................................9

Section 1.04      Location of Emergency Generator and UPS.........................................................9


ARTICLE II - LEASE TERM...........................................................................................9

         Section 2.01      Lease Term.............................................................................9

         Section 2.02      Holding Over..........................................................................10


ARTICLE III - RENT ..............................................................................................11

         Section 3.01      Base Rent.............................................................................11

         Section 3.02      Additional Rent.......................................................................11

         Section 3.03      Prepaid Rent (Intentionally Omitted)..................................................17

         Section 3.04      Rent Payments.........................................................................18

         Section 3.05      Security..............................................................................18


ARTICLE IV - UTILITIES AND SERVICES..............................................................................22

         Section 4.01      Services to be Provided...............................................................22

         Section 4.02      Tenant's Obligations..................................................................24

         Section 4.03      Service Interruptions.................................................................24

         Section 4.04      Modification..........................................................................25


ARTICLE V - USE AND OCCUPANCY....................................................................................26

         Section 5.01      Use and Occupancy.....................................................................26

         Section 5.02      Rules and Regulations.................................................................27

         Section 5.03      Quiet Enjoyment.......................................................................27


ARTICLE VI - REPAIRS, MAINTENANCE AND ALTERATIONS................................................................27

         Section 6.01      Repair and Maintenance by Tenant......................................................27

         Section 6.02      Alterations and Additions by Tenant...................................................28

         Section 6.03      Mechanics' Liens - Tenant's Obligations...............................................29

         Section 6.04      Maintenance and Repair by Landlord....................................................29


ARTICLE VII - INSURANCE, FIRE AND CASUALTY.......................................................................30

         Section 7.01      Tenant's Insurance....................................................................30

         Section 7.02      Landlord's Insurance..................................................................30

         Section 7.03      Fire or Other Casualty................................................................31

         Section 7.04      Waiver of Subrogation.................................................................32


ARTICLE VIII - CONDEMNATION......................................................................................33

ARTICLE IX - INDEMNIFICATIONS AND WAIVERS........................................................................34

         Section 9.01      Limitations on Liability of Landlord and Waivers......................................34
</TABLE>



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<PAGE>   3



<TABLE>
<S>                                                                                                             <C>
         Section 9.02      No Implied Waiver.....................................................................34

         Section 9.03      Waiver by Tenant......................................................................35

         Section 9.04      Hazardous Substances..................................................................35


ARTICLE X - ASSIGNMENT AND SUBLETTING............................................................................36

         Section 10.01     No Assignment or Subletting Without Consent...........................................36

         Section 10.02     Landlord's Consent....................................................................37

         Section 10.03     Permitted Transfers...................................................................38


ARTICLE XI - DEFAULT.............................................................................................38

         Section 11.01     Default...............................................................................38

         Section 11.02     Landlord's Lien.......................................................................41

         Section 11.03     Mitigation of Damages.................................................................41


ARTICLE XII - MISCELLANEOUS PROVISIONS...........................................................................43

         Section 12.01     Rights Reserved by Landlord...........................................................43

         Section 12.02     Taxes on Tenant's Property............................................................45

         Section 12.03     Attorneys' Fees and Legal Expenses....................................................45

         Section 12.04     Subordination.........................................................................45

         Section 12.05     Estoppel Certificates.................................................................46

         Section 12.06     Financial Statements..................................................................46

         Section 12.07     Notices...............................................................................46

         Section 12.08     Business Purpose......................................................................47

         Section 12.09     Severability..........................................................................47

         Section 12.10     No Merger.............................................................................47

         Section 12.11     Force Majeure.........................................................................47

         Section 12.12     Gender................................................................................48

         Section 12.13     Joint and Several Liability...........................................................48

         Section 12.14     No Representations....................................................................48

         Section 12.15     Entire Agreement; Amendments..........................................................48

         Section 12.16     Section Headings......................................................................48

         Section 12.17     Binding Effect........................................................................48

         Section 12.18     Counterparts..........................................................................48

         Section 12.19     Rental Tax............................................................................49

         Section 12.20     Authority to Sign Lease...............................................................49

         Section 12.21     Execution and Approval of Lease.......................................................49

         Section 12.22     Time of the Essence...................................................................49

         Section 12.23     No Personal Liability of Landlord or Guarantor .......................................49





ARTICLE XIII - ADDITIONAL AGREEMENTS.............................................................................50

         Section 13.01     Parking...............................................................................50

         Section 13.02     Signage...............................................................................51

         Section 13.03     Tenant's Ability to Perform Landlord's Unperformed Obligations........................51
</TABLE>



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<PAGE>   4


<TABLE>
<S>                                                                                                             <C>
         Section 13.04     Real Estate Brokers...................................................................52

         Section 13.05     Conditions Precedent..................................................................52

         Section 13.06     Title, Survey and Environmental Report................................................53

         Section 13.07     Covenants of Landlord.................................................................53

         Section 13.08     Entry by Landlord.....................................................................54

         Section 13.09     Tenant's Purchase Option..............................................................54

         Section 13.10     Joint Approval of Press Releases......................................................56


ARTICLE XIV - EXHIBITS AND ATTACHMENTS...........................................................................56
</TABLE>



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<PAGE>   5



                             BASIC LEASE PROVISIONS


LANDLORD:                           Desta Five Partnership, Ltd., a Texas
                                    limited partnership

LANDLORD'S ADDRESS:                 6 Desta Drive, Suite 6500
                                    Midland, Texas  79705
                                    Attn: Mr. L. Paul Latham
                                    Telephone No. (915) 688-3212
                                    Fax No. (915) 688-3247

                                    with copy to:

                                    Desta Five Partnership, Ltd.
                                    2700 Via Fortuna, Suite 140
                                    Austin, Texas  78746
                                    Attn: Mr. Rod Arend
                                    Telephone No. (512) 306-9093
                                    Fax No. (512) 306-9112

TENANT:                             Cirrus Logic, Inc.

TENANT'S ADDRESS PRIOR
TO COMMENCEMENT DATE:               4210 South Industrial Drive
                                    Austin, Texas  78744
                                    Attention: General Counsel
                                    Telephone No. (512) 912-3929
                                    Fax No. (512) 912-3998

                                    with copy to:

                                    4210 South Industrial Drive
                                    Austin, Texas  78744
                                    Attention:  Treasurer
                                    Telephone No. (512) 912-3826
                                    Fax No. (512) 445-6332

TENANT'S ADDRESS AFTER
COMMENCEMENT DATE:                  2901 Via Fortuna, Suite 100
                                    Austin, Texas 78746
                                    Attention: General Counsel
                                    Telephone No. (512) __________________
                                    Fax No. (512)________________________




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<PAGE>   6
                                    with copy to:

                                    2901 Via Fortuna, Suite 100
                                    Austin, Texas 78746
                                    Attention:  Treasurer
                                    Telephone No. (512) __________________
                                    Fax No. (512)________________________

BUILDING:                           The land described on Exhibit A attached
                                    hereto (the "Land"), together with all
                                    improvements constructed or to be
                                    constructed thereon, including all building
                                    systems which are included within and/or
                                    serve the Building and the related parking
                                    garage located on the Land (the "Garage").
                                    The floor plans of the Building are
                                    generally depicted on Exhibit B attached
                                    hereto. The Building will be known as, 2901
                                    Via Fortuna, Austin, Texas 78746.

LEASED PREMISES:                    All of the Building and the Land.

TOTAL BUILDING AREA:                192,000 square feet of Rentable Area,
                                    subject to adjustment as provided in
                                    Paragraph 1.01.

BASE RENT:                          Beginning on the Commencement Date, Base
                                    Rent under this Lease will be payable in an
                                    amount as calculated pursuant to Section
                                    3.01 of the Lease. As soon as possible after
                                    "Project Cost", as defined herein, is
                                    determined, but not later than the
                                    Commencement Date, Landlord and Tenant shall
                                    enter into an amendment to this Lease to
                                    provide for the actual Base Rent in the
                                    Table set forth below:

<TABLE>
<CAPTION>
                                       Lease Months           Annual Rate            Monthly Installments
                                    -------------------------------------------------------------------------
<S>                                 <C>                  <C>                    <C>
                                    1 - 120              Approx. $24.76          approx. $396,160
                                                         Per square foot of
                                                         Rentable Area per
                                                         year
                                    -------------------------------------------------------------------------
</TABLE>

RENT:                               The Base Rent, Additional Rent (hereinafter
                                    defined), and all other amounts payable by
                                    Tenant to Landlord under this Lease.

TENANT'S PERCENTAGE:                One Hundred percent (100%);

EFFECTIVE DATE:                     November 10, 2000

COMMENCEMENT DATE:                  Anticipated to be September 1, 2002; the
                                    actual Commencement Date will be determined
                                    in accordance with Section 2.01(a).

LEASE TERM:                         One Hundred Twenty (120) months, commencing
                                    on the Commencement Date and subject to the
                                    option to extend set forth on Exhibit H.



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<PAGE>   7
BUILDING STANDARD HOURS:            7:00 a.m. to 7:00 p.m. on each Monday
                                    through Friday (excluding Building Holidays)
                                    and 8:00 a.m. to 5:00 p.m. on each Saturday
                                    (excluding Building Holidays), subject to
                                    the modifications set forth in Section
                                    4.01(b). Notwithstanding the foregoing
                                    recitation of Building Standard Hours or any
                                    other provision in this Lease to the
                                    contrary, it is agreed and understood that
                                    Tenant and Tenant's authorized employees
                                    shall have free and uninterrupted access to
                                    the Leased Premises at all times (24 hours
                                    per day, 7 days per week).

BUILDING HOLIDAYS:                  New Years Day, Memorial Day, Independence
                                    Day, Labor Day, Thanksgiving Day and
                                    Christmas Day.

TENANT'S BROKER:                    NAI Commercial Industrial Properties Company
                                    7320 N. Mopac Expressway, Suite 100 Austin,
                                    Texas 78731

LANDLORD'S BROKER:                  Colliers Oxford Commercial, Inc.
                                    2700 Via Fortuna Drive, Suite 100
                                    Austin, Texas 78748

SECURITY:                           A cash deposit of $540,160 plus a $9,000,000
                                    Letter of Credit, as may be adjusted
                                    pursuant to Section 3.05.

PARKING:                            Tenant shall be entitled to utilize all of
                                    the parking spaces in the Garage (which will
                                    be at least 768 parking spaces and all of
                                    the surface parking spaces which are located
                                    upon the Land), all at no cost to Tenant.

PERMITTED USE                       General office uses, uses related to
                                    integrated circuit design, and uses which
                                    are ancillary or appurtenant to the
                                    foregoing, including, but not limited to
                                    training centers, cafeterias, computer
                                    rooms, data and word processing centers, and
                                    research services use including research
                                    laboratories in which testing and
                                    verification of electrical products occurs
                                    in accordance with applicable city zoning
                                    ordinances.
The Basic Lease Provisions set forth hereinabove are hereby incorporated into
and made a part of the Lease Agreement which is attached hereto (the "Lease").
Each reference in the Lease to any of the provisions or definitions set forth in
these Basic Lease Provisions shall mean and refer to the provisions and
definitions hereinabove set forth and shall be used in conjunction with the
provisions of the Lease. In the event of any direct conflict between these Basic
Lease Provisions and the Lease, these Basic Lease Provisions shall control;
provided, however, that those provisions in the Lease (including all exhibits
and attachments thereto) which expressly require an adjustment or modification
to any of the matters set forth in these Basic Lease Provisions shall supersede
the adjusted or modified provisions of these Basic Lease Provisions.

EXECUTED by the undersigned in multiple originals as of the Effective Date set
out hereinabove.


LANDLORD:                           DESTA FIVE PARTNERSHIP, LTD., a Texas
                                    limited partnership

                             By:    DESTA FIVE DEVELOPMENT CORP., a Texas
                                    corporation, its general partner


                             By:
                                                   L. Paul Latham, President


TENANT:                             CIRRUS LOGIC, INC.


                                   By:


                                   Name:
                                        ----------------------------------------

                                   Title:


                                       7
<PAGE>   8



                                 LEASE AGREEMENT

         This Lease Agreement ("Lease") is entered into as of the Effective Date
specified in the Basic Lease Provisions by and between Landlord and Tenant. The
Basic Lease Provisions attached hereto and the defined terms set out therein are
hereby incorporated herein by reference.

                           ARTICLE I - LEASED PREMISES

Section 1.01 Leased Premises

         The Leased Premises will include the entire Rentable Area of the
         Building as depicted on Exhibit B. Landlord and Tenant acknowledge and
         agree that the Rentable Area as stated in the Basic Lease Provisions is
         an approximate number and cannot be conclusively determined until after
         completion of construction of the Building. Within forty-five (45) days
         following the Substantial Completion date (as hereinafter defined), the
         Rentable Area of the Building will be determined and certified in
         writing to Landlord and Tenant by Landlord's architect, using the "BOMA
         Method" described below. In the event that Tenant disputes the
         calculation by the Landlord's architect of Rentable Area of the
         Building, then Tenant may cause its architect to measure the Leased
         Premises and/or Building in the manner provided herein and to deliver
         its own architect's certificate to Landlord within thirty (30) days
         after receipt of the Landlord's architect's certificate. Landlord and
         Tenant will endeavor in good faith for a period of twenty (20) days
         after receipt of the Tenant's architect's certificate to agree on the
         Rentable Area of the Building. In the event that Landlord and Tenant
         cannot agree within such twenty (20) day period, then Landlord's and
         Tenant's architects will within ten (10) days thereafter jointly select
         a third licensed architect to review the architect's certificates and
         related back-up



                                       8
<PAGE>   9



         materials and such architect will make a determination of Rentable Area
         based on the materials provided within fifteen (15) days after being so
         selected. Absent gross error, the determination of the third architect
         will be final and binding on Landlord and Tenant. As used herein, "BOMA
         Method" shall mean the method for measuring floor area in office
         buildings as set out in ANSI/BOMA Z65.1- 1996.

Section 1.02 Lease Grant

         For the consideration and subject to the terms, provisions and
         conditions set out below, Landlord lets and leases to Tenant and Tenant
         leases from Landlord the Leased Premises.

Section 1.03 Building Core and Shell

         Landlord will provide the improvements which are listed and described
         on Exhibit C which is attached hereto and incorporated herein by
         reference (the "Building Design Development Criteria"). The
         improvements to be constructed by Landlord within the Leased Premises
         are set forth in the "Tenant Work Letter" which is attached to this
         Lease as Exhibit M and incorporated herein by reference (the "Tenant
         Work Letter"). Notwithstanding any provisions herein to the contrary,
         none of the provisions in the Tenant Work Letter will be construed to
         modify Landlord's obligation to construct the Building Core and Shell
         in accordance with Exhibit C attached hereto and incorporated herein by
         reference.

Section 1.04 Location of Emergency Generator and UPS

         Landlord agrees that, at Tenant's option and election: (i) Tenant may
         install an emergency generator (150 kw to 250 kw in size) with self
         contained fuel tanks ("Generator"); or (ii) Landlord will increase the
         size and capacity of Landlord's generator in an amount sufficient to
         cover Tenant's internal needs. If Tenant elects to install the
         Generator, then Landlord agrees to provide Tenant with a location for
         the Generator in the office building portion of the Building. The
         location of the Generator must be mutually agreed upon by Landlord and
         Tenant. Tenant shall have the right to run conduit from the Generator
         to the Leased Premises at Tenant's sole cost. Tenant will also have the
         right to install uninterruptible power supplies ("UPS") as required to
         support areas within the Leased Premises such as labs, computer server
         equipment and telecommunications equipment. The cost of the Generator
         and UPS will be borne as part of the Allowance as provided for in the
         Tenant Work Letter.

                             ARTICLE II - LEASE TERM

Section 2.01 Lease Term

         (a) For purposes of this Lease, the "Commencement Date" shall mean and
         refer to the date upon which all of the following (collectively, the
         "Completion Items") have occurred: (i) Base Building Substantial
         Completion (as said terms are defined in the Tenant Work Letter) has
         occurred; (ii) Substantial Completion of the Tenant Finish Work (as
         said terms are defined in the Tenant Work Letter) has occurred; and
         (iii) Landlord has delivered possession of the Leased Premises to
         Tenant. Landlord shall permit Tenant and Tenant's agents to have access
         to the Leased Premises during the forty-five (45) day period prior to



                                       9
<PAGE>   10



         the Commencement Date in order that Tenant may install Tenant's
         furniture and equipment (including telecommunications and computer
         wiring and equipment). Notwithstanding any provision herein to the
         contrary, the Commencement Date shall not occur until the foregoing
         referenced forty-five (45) day period has been provided to Tenant.

         (b) Subject to and upon the terms and conditions set forth in the
         Lease, or in any exhibit attached hereto, the primary term of this
         Lease shall commence on the Commencement Date and shall expire on the
         last day of the one hundred twentieth (120th) month following the
         Commencement Date or such earlier date as this Lease may terminate as
         provided herein (the "Expiration Date"). The "Lease Term" of this Lease
         shall be the primary term specified in this Section 2.01, as renewed or
         otherwise extended or earlier terminated pursuant to the terms and
         provisions set forth herein. If the Commencement Date is not the first
         day of a calendar month, then the Lease Term shall be extended by the
         time between the Commencement Date and the first day of the next month.

         (c) After the Commencement Date, Landlord and Tenant shall promptly,
         upon the request of either of them, execute and deliver to each other
         an agreement setting forth the Commencement and Expiration Dates.

         (d) This Lease is being executed before the Leased Premises are
         available and ready for occupancy. Landlord and Tenant currently
         anticipate that the Completion Items will be completed on or before
         September 1, 2002 (the "Scheduled Commencement Date"). If the
         Completion Items are not completed on or before the Scheduled
         Commencement Date: (i) Landlord shall not be in default hereunder or be
         liable for damages therefor, but Tenant shall be entitled to two (2)
         days abatement of Rent under this Lease (from and after the actual
         Commencement Date) for each day that lapses between the Scheduled
         Commencement Date and the actual Commencement Date; and (ii) Tenant
         shall accept possession of the Leased Premises after the Completion
         Items are actually completed.

Section 2.02 Holding Over

         Should Tenant hold the Leased Premises after termination of this Lease,
         by lapse of time, default, or otherwise, such holding over shall be
         construed as a tenancy at sufferance only, and Tenant shall pay in
         advance, as Rent, for each day of such holding, a per diem amount equal
         to 1/30 of one hundred fifty percent (150%) of the Rent payable for the
         last month of the Lease Term. No receipt of money by Landlord from
         Tenant after termination of this Lease shall reinstate or extend this
         Lease, or affect any prior notice given by Landlord to Tenant, and no
         extension shall be valid unless in writing, signed by Landlord and
         Tenant. The foregoing shall not be construed as Landlord's consent for
         any such holding over, and Landlord reserves the right to proceed
         against Tenant for any actual damages caused thereby.



                                       10
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                               ARTICLE III - RENT

Section 3.01 Base Rent

         (a) Landlord and Tenant agree that the annual Base Rent (per rentable
         square foot) shall be equal to twelve percent (12%) of the actual
         "Project Cost" (allocated on a per-rentable-square-foot basis). The
         term "Project Cost" is defined in the Tenant Work Letter. Landlord will
         develop and present to Tenant for approval a proposed budget which
         reflects the anticipated Project Cost (the "Project Cost Budget").
         Tenant will, within ten (10) business days after receipt of Landlord's
         proposed Project Cost Budget, either approve or disapprove the same in
         writing, with such approval not to be unreasonably withheld. In the
         event of disapproval, Landlord and Tenant will meet and use good faith
         efforts to arrive at a mutually agreeable disposition of the objection
         or objections raised by Tenant. Landlord agrees it will not
         unreasonably withhold approval to any cost reduction proposals if
         requested by Tenant. If Landlord and Tenant are unable to agree,
         Landlord's decision shall prevail. Notwithstanding any provision herein
         to the contrary: (i) Landlord and Tenant agree to work together to
         design and engineer the Building with the objective of achieving a Base
         Rent rate of $24.00 per rentable square foot per year or less; and (ii)
         Landlord agrees the Base Rent shall not, in any event, exceed $26.40
         per rentable square foot per year.

         (b) Tenant shall pay the Base Rent to Landlord in monthly installments
         in advance on or before the first day of each calendar month during the
         Lease Term. If the Lease Term is extended for a partial month under the
         terms of Section 2.01(a) hereinabove, then the Lease Months referenced
         in the Base Rent table set out in the Basic Lease Provisions will begin
         on the first day of the next full calendar month after the Commencement
         Date and Base Rent will be calculated for the partial month at the
         beginning of the Lease Term at the same rate as is provided with
         respect to the first Lease Month. Base Rent for any partial calendar
         month will be prorated on a per diem basis.

         (c) Landlord and Tenant have agreed to estimate the annual Base Rent to
         be $24.76 per rentable square foot. This estimate is based on the pro
         forma calculations set forth on Attachment 2 to the Tenant Work Letter
         and is attached for the sole purpose of establishing the formula for
         calculating the actual annual Base Rent when all Project Costs are
         determined.

Section 3.02 Additional Rent

         (a) For purposes of this Lease "Operating Expenses" means all of
         Landlord's reasonable, necessary and customary costs and expenses paid
         or incurred by Landlord in owning, operating, managing and maintaining
         the Building for a particular calendar year or portion thereof (subject
         to the exclusions provided for hereinbelow), determined on the cash
         basis and otherwise in accordance with Generally Accepted Accounting
         Principles ("GAAP") consistently applied, including by way of
         illustration but not limitation: (i) all taxes, assessments and
         governmental charges of any kind and nature whatsoever levied or
         assessed against the Building; (ii) any and all assessments
         attributable to the Building and levied by the planned unit development
         (the "Terrace P.U.D.") owner's association; (iii) all premiums for any
         and all insurance maintained in connection with the ownership,
         operation, maintenance, and/or management of the Building (including
         but not limited to property and liability coverage); (iv) water, sewer,
         electrical and other utility charges; (v) service and other charges
         incurred in the operation and maintenance of the elevators and the
         heating, ventilation and air-conditioning system; (vi) cleaning and
         other janitorial



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         services; (vii) tools and supplies; (viii) repair costs (but excluding
         capital repairs as provided herein below); (ix) landscape maintenance
         costs (the Operating Expenses will not include any costs incurred for
         initial landscape installation); (x) security services; (xi) license,
         permit and inspection fees other than that required for Tenant's
         interior improvements; (xii) reasonable management fees (during the
         initial Lease Term, the management fees charged in any year will not
         exceed four percent (4%) of the Base Rent and the Additional Rent
         payable by Tenant during such year); (xiii) wages and related benefits
         payable to employees who render services to or for the direct benefit
         of the Building or tenants of the Building and are not managerial
         services covered by the management fee; (xiv) legal and accounting
         fees; (xv) trash removal; (xvi) Garage maintenance and operating costs;
         (xvii) the cost of electrical surveys, not to exceed $2,000 in any
         annual period; (xviii) capital improvements costing less than five
         thousand dollars ($5,000) (amortized under GAAP) which is limited to
         all capital improvements and capital repairs, including repairs to or
         replacements of the building structure, building systems, the Garage;
         and, in general, (xiv) all other costs and expenses which would
         generally be regarded as operating and maintenance costs and expenses.
         Also included in Operating Expenses is the cost of any capital
         improvement made to the Building by Landlord after the date of this
         Lease that is required under governmental law or regulation not
         applicable to the Building at the time the Building was constructed,
         amortized over a period Landlord reasonably determines to be the useful
         life of the improvements, together with an amount equal to interest at
         the rate of ten percent (10%) per annum on the unamortized balance.

         Landlord may, with the prior written approval of Tenant (not to be
         unreasonably withheld) install any device, improvement or equipment
         which will improve the operating efficiency of any system within the
         Building (e.g. solar collectors) or reduce Operating Expenses. Landlord
         may add to the Operating Expenses each year during the useful life of
         any device, improvement, or equipment installed under the terms of the
         preceding sentence (as the useful life is determined under GAAP) in an
         amount equal to the annual amortization of the cost of the installed
         device, improvement, or equipment, calculated on a straight line basis
         over the useful life, but such amortized costs shall only be included
         in Operating Expenses for that portion of the useful life of the
         included capital item which falls within the Lease Term.

         Landlord estimates that the Additional Rent during the initial year of
         the Lease Term will be an amount not in excess of (i) the number of
         square feet of Rental Area in the Leased Premises multiplied by (ii)
         $9.00.

         (b) Operating Expenses shall not include costs for:

                  (i) repair, replacements and general maintenance paid by
                  proceeds of insurance or by Tenant or other third parties;

                  (ii) interest, amortization or other payments on loans to
                  Landlord;

                  (iii) leasing commissions and expenses;



                                       12
<PAGE>   13



                  (iv) legal or accounting expenses for services, other than
                  those that benefit the Building tenants generally (e.g., tax
                  disputes);

                  (v) renovating or otherwise improving space for occupants or
                  prospective occupants of the Building or vacant space in the
                  Building;

                  (vi) the costs incurred by Landlord to bring the Building, the
                  Land or any equipment maintained therein in compliance with
                  laws, ordinances, rules, regulations, requirements,
                  directives, guidelines and orders in effect and applicable to
                  the Building as of the Commencement Date of this Lease;

                  (vii) the cost of any services or materials supplied to other
                  tenants and not to Tenant;

                  (viii) the cost of any services or materials for which
                  Landlord receives reimbursement from other sources;

                  (ix) depreciation on the Building;

                  (x) franchise taxes or federal income taxes imposed on or
                  measured by the income of Landlord from the operation of the
                  Building;

                  (xi) repairs, alterations, additions, improvements,
                  replacements made to rectify or correct any defect in the
                  original design, materials or workmanship of the Building
                  other than repairs, alterations, additions, improvements or
                  replacements made as a result of ordinary wear and tear;

                  (xii) damage and repairs attributable to fire or other
                  casualty;

                  (xiii) damage and repairs necessitated by the gross negligence
                  or willful misconduct of Landlord, Landlord's employees,
                  contractors or agents;

                  (xiv) executive salaries or salaries of service personnel to
                  the extent that the services of such persons do not relate to
                  the direct management, operation, repair or maintenance of the
                  Building;

                  (xv) Landlord's general overhead and administrative expenses
                  not incurred in the direct operation of the Building
                  (including salaries, fringe benefits and other compensation
                  paid to partners, officers, and executives of Landlord);

                  (xvi) costs including permit, license and inspection fees
                  incurred in renovating or otherwise improving, decorating or
                  painting or altering space for tenants or other occupants or
                  of vacant space in the Building;

                  (xvii) legal fees, fines, penalties, and similar costs
                  incurred due to a violation by Landlord of the terms and
                  conditions of this or any other lease;



                                       13
<PAGE>   14



                  (xviii) cost of any service provided to Tenant or other
                  occupants of the Building for which Landlord is reimbursed or
                  has received reimbursement from another source;

                  (xix) interest on debt or principal amortization payments on
                  any mortgages or deeds of trust or rental payments on any
                  ground lease of the Land or any other debt for borrowed money;

                  (xx) costs of repairs or replacements incurred by reason of
                  fire, windstorm, other insured casualty or condemnation
                  (except to the extent of any deductible or not covered by
                  insurance or condemnation proceeds);

                  (xxi) the cost of installing, operating and maintaining any
                  specialty service, such as a luncheon club, athletic or
                  recreational club, except to the extent provided to all
                  tenants at no charge and for which rent is not collected from
                  any occupant thereof;

                  (xxii) the cost of any work or service performed for any
                  facility other than the Building except service areas
                  benefitting the Building located in facilities other than in
                  the Building;

                  (xxiii) the cost of capital improvements other than
                  specifically provided in Section 3.02(a) above;

                  (xxiv) insurance premiums to the extent Landlord is
                  specifically reimbursed therefore by another tenant other than
                  as part of Operating Expenses;

                  (xxv) any costs included in Operating Expenses representing an
                  amount paid to any person or entity related to Landlord which
                  is in excess of the amount which would have been paid in the
                  absence of such relationship;

                  (xxvi) rentals and other related expenses incurred in leasing
                  air conditioning systems, elevators or other Building
                  equipment ordinarily considered to be of a capital nature, the
                  cost of which equipment would not constitute an expense under
                  GAAP consistently applied if the equipment were purchased;

                  (xxvii) any expense for repairs or maintenance to the extent
                  such costs are recovered under warranties or service
                  contracts;

                  (xxviii) legal and auditing fees which are for the benefit of
                  Landlord such as preparing tax returns and financial
                  statements;

                  (xxix) the wages of any employee for services not related
                  directly to the management, maintenance, operation and repair
                  of the Building;

                  (xxx) charitable contributions;

                  (xxxi) costs of removal, abatement or treatment of any
                  Hazardous Substances in or under the Building or Land
                  associated therewith, to the extent such costs are



                                       14
<PAGE>   15



                  incurred as a result of any act, omission, or negligence of
                  Landlord or its agents, employees or contractors;

                  (xxxii) electrical power costs above normal consumption for
                  which any tenant is separately metered or directly contracts
                  with the local public service company;

                  (xxxiii) overhead and profit increment paid to Landlord or to
                  subsidiaries or affiliates of Landlord for services or
                  materials in the Building to the extent the same exceeds the
                  market costs of such services or materials rendered by
                  comparable unaffiliated third parties on a competitive basis;

                  (xxxiv) costs of purchasing paintings, sculptures or other art
                  work for display in the Building unless approved by Tenant;

                  (xxxv) costs incurred primarily in connection with the sale,
                  financing, refinancing, mortgaging, selling or change of
                  ownership of Landlord, the Building or the Land;

                  (xxxvi) management fees in excess of the then-prevailing
                  market rate (and during each year of the initial Lease Term,
                  such management fees will not exceed four percent (4%) of the
                  Base Rent and Additional Rent paid by Tenant under this Lease
                  during such year);

                  (xxxvii) late charges, fines, penalties and interest incurred
                  by Landlord for its failure to pay timely any item which is
                  included in the Operating Expenses unless caused by Tenant;

                  (xxxviii) bad debt loss, rent loss, or reserves for either of
                  these, and any other reserves for repairs, maintenance or
                  replacements unless pursuant GAAP;

                  (xxxix) capital repairs and capital improvements in excess of
                  the $5,000 per year expressly allowed under Section 3.02(a)
                  (xviii); and

                  (xxxx) any items which are included in the Project Cost (but
                  not the repair or replacement of such items).

         (c) In addition to the Base Rent, Tenant shall pay to Landlord as
         Additional Rent for the Leased Premises, in each calendar year, or
         partial calendar year, during the Lease Term, an amount equal to
         Tenant's Percentage of the Operating Expenses for the calendar year or
         portion of the calendar year.

         (d) Landlord shall estimate Tenant's Additional Rent for each
         subsequent calendar year, and give written notice thereof to Tenant by
         April 1 of each year. Landlord's estimate of Tenant's Additional Rent
         shall include a budget in reasonable detail of the anticipated
         Operating Expenses for the then current calendar year. If Tenant
         objects to the amount of the estimated Additional Rent or to any
         expenses reflected in the Operating Expenses budget, Landlord shall
         meet with Tenant and use Landlord's good faith efforts to address
         Tenant's concerns and to reduce the Operating Expenses and Tenant's
         Additional Rent. In all events, Landlord agrees that Landlord will
         utilize good faith efforts to



                                       15
<PAGE>   16



         minimize Operating Expenses, taking into account, however, the
         operating and maintenance standards which are applicable to Landlord
         under the terms of this Lease.

         (e) For each calendar year (or partial calendar year) Tenant shall pay
         to Landlord each month, at the same time the Base Rent is due, an
         amount equal to one-twelfth (1/12) of the estimated annual Additional
         Rent due; provided that, Landlord agrees that in calendar year 2004 and
         subsequent calendar years, Operating Expenses which may be controlled
         by Landlord shall not increase more than six percent (6%) on an annual
         cumulative basis. For these purposes Operating Expenses over which
         Landlord has no control shall mean: (i) ad valorem taxes, assessments
         and governmental charges or impositions of any kind or nature
         whatsoever which are levied against the Building (provided, however,
         that Landlord shall utilize reasonable efforts to protest any tax
         appraisals which are above fair market value and Landlord will utilize
         other reasonable efforts to minimize ad valorem taxes and assessments
         against the Building); (ii) premiums for any and all property,
         casualty, worker's compensation and/or other insurance Landlord is
         required to maintain or chooses to maintain under the terms of this
         Lease (provided, however, that Landlord shall use reasonable efforts to
         minimize insurance costs); or (iii) impositions, charges or fees of
         whatever kind or nature for water, sewer, gas, electric or other
         utilities (provided, however, Landlord will use reasonable efforts to
         minimize utility expenses). For any year during which Additional Rent
         is due for less than the entire calendar year, Tenant shall pay to
         Landlord each calendar month during such year, one-twelfth of the
         estimated Additional Rent that would have been due if Additional Rent
         had been due throughout that calendar year.

         (f) If Operating Expenses increase during a calendar year, Landlord may
         revise the estimated Additional Rent during such year by giving Tenant
         at least thirty (30) days advance written notice to that effect, and
         thereafter Tenant shall pay to Landlord, in each of the remaining
         months of that calendar year, an additional amount equal to the amount
         of the increase in the estimated Additional Rent divided by the number
         of months remaining in the year. Notwithstanding the foregoing,
         Landlord may not revise the estimated Additional Rent more than two (2)
         times during any given calendar year.

         (g) Within one hundred twenty (120) days after the end of each calendar
         year, Landlord shall prepare and deliver to Tenant a statement showing
         Tenant's actual Additional Rent for that calendar year. The statement
         shall separately set forth the basic components (in reasonable detail)
         of Additional Rent for the prior calendar year and shall be certified
         as correct by a certified public accountant or an accounting firm, or
         if such statement is not audited, certified by the Building's manager,
         and if reasonably requested by Tenant, Landlord shall provide Tenant
         with a supplemental statement setting forth the applicability of such
         costs and the rationale behind the allocation thereof. Within thirty
         (30) days after receipt of each statement, Tenant shall pay to
         Landlord, or Landlord shall credit against the next Additional Rent
         payment or payments due from Tenant, as the case may be, the difference
         between Tenant's actual Additional Rent for the preceding calendar year
         and the estimated Additional Rent paid by Tenant during the year.

         (h) Tenant will have the right, for a period of two (2) years after the
         expiration of any calendar year (but not thereafter) to audit
         Landlord's books, at Tenant's cost and expense, to verify the Operating
         Expenses for such calendar year. If Tenant does not request an



                                       16
<PAGE>   17



         audit within two (2) years after the expiration of any particular
         calendar year, then Tenant will be deemed to have waived any right it
         may have to an adjustment to Tenant's Percentage of any Operating
         Expenses for such calendar year. If it is finally determined that
         Tenant's actual share of Additional Rent is different than Landlord's
         computation of Tenant's share of Additional Rent, then Landlord shall
         refund to Tenant any overpayment of any such costs for the year in
         question and for each year during the Term the same error was made or
         Tenant shall pay to Landlord any underpayment of any such costs for the
         year in question and for each year during the Lease Term the same error
         was made, as the case may be, within thirty (30) days after
         notification thereof. All such audits shall be performed at Tenant's
         expense unless it is finally determined that the statement for the time
         period in question was in error and, as a result thereof, Tenant paid
         to Landlord more than (A) 102.5% of the Additional Rent due for such
         time period, in which case Landlord shall pay one half of the
         reasonable out-of-pocket audit costs of Tenant; or (B) 105% of the
         Additional Rent due for such time period, in which case Landlord shall
         pay all reasonable out-of-pocket audit costs of Tenant.

         (i) Tenant's right to verify Operating Expenses shall be subject to the
         following limitations and conditions: (i) Tenant shall have provided
         Landlord with a timely written notice of its desire to verify Operating
         Expenses and specified a date for such verification not less than ten
         (10) days nor more than thirty (30) days from the delivery of the
         notice to Landlord; (ii) such review or verification shall take place
         in Landlord's offices; and (iii) Tenant and any third party auditor or
         reviewer employed by Tenant shall execute and deliver to Landlord a
         confidentiality agreement reasonably acceptable to Landlord and which
         shall include, among other terms, the agreement of Tenant and such
         third party not to disclose to any other person the existence of the
         review, the results of the review and the agreement of any third party
         not to solicit verifications or reviews on the part of any other tenant
         of the Building.

         (j) In the event Landlord and Tenant are unable to agree on the
         appropriate resolution of any dispute relating to Operating Expenses,
         the sole and exclusive remedy of Tenant shall be to submit the
         appropriate determination of Operating Expenses to binding arbitration
         in Travis County, Texas in accordance with the rules of the American
         Arbitration Association for commercial disputes. In the event Landlord
         and Tenant can not agree on a panel of arbiters within ten (10) days
         after either party notifies the other of its election to submit the
         matter to arbitration, then Landlord and Tenant shall each appoint an
         arbitrator and the two arbitrators selected shall appoint the third.
         All arbitrators selected or appointed for resolution of the dispute
         shall be unaffiliated with the parties and shall have at least ten (10)
         years experience in commercial real estate leasing in Travis County,
         Texas as either an attorney or a licensed real estate broker. The
         arbitration panel shall render a decision within ninety (90) days of
         appointment.

Section 3.03 Prepaid Rent

         Intentionally omitted.



                                       17
<PAGE>   18



Section 3.04 Rent Payments

         (a) All Rent is payable by Tenant at the times and in the amounts
         specified in this Lease in legal tender of the United States of America
         to Landlord at Landlord's management office in the Terrace P.U.D., or
         to any other person or at any other address as Landlord may from time
         to time designate in the continental United States by prior written
         notice to Tenant.

         (b) Rent is payable by Tenant without notice, demand, abatement,
         deduction, or set-off except as expressly specified in this Lease.
         Tenant's obligation to pay Rent is independent of any obligation of
         Landlord under this Lease. If any installment of: (i) Base Rent or
         Additional Rent is not paid within five (5) business days after it is
         due; or (ii) any other Rent is not paid within fifteen (15) business
         days after it is due, Tenant shall pay to Landlord a late charge in an
         amount equal to two and one half percent (2 1/2%) of the delinquent
         installment of Rent when it pays the delinquent installment. In
         addition, if Tenant fails to pay any Rent within five (5) business days
         when the same is due (and such Rent represents amounts not already
         specified as bearing interest under other provisions of this Lease)
         then Tenant shall also pay to Landlord interest on the unpaid Rent from
         the due date until the date paid at the highest rate lawfully permitted
         to be contracted for, charged or received pursuant to a written
         contract under applicable federal or state law (the lower of such rates
         being referred to herein as the "Interest Rate").

Section 3.05 Security

         (a) Tenant and Landlord hereby acknowledge and agree that Landlord has
         been asked to contribute the value of the Land and its personnel,
         resources and expertise toward the development of the Land and the
         construction thereon of the Building to Tenant's specifications for the
         purpose of leasing the same to Tenant and, but for the agreements of
         Tenant herein regarding, in particular, the payment of Base Rent during
         the first seven (7) years of the Lease Term, Landlord would not agree
         to construct the Building, obtain a loan to finance such construction
         (herein, the "Construction Loan"), or enter into this Lease. Tenant and
         Landlord acknowledge and agree that this Lease shall serve to evidence
         the obligations of Landlord, as developer, regarding the development of
         the Land and the construction of the Building and also the obligations
         of Landlord and Tenant, as lessor and lessee. Landlord and Tenant have
         identified certain development costs that will be incurred by Landlord
         including (i) amounts to be expended by Landlord in connection with the
         performance of Landlord's obligations hereunder and the delivery of the
         Leased Premises to Tenant on or before the Commencement Date of the
         Lease (including, specifically, the costs of Tenant Finish Work,
         brokerage commissions, and Landlord's overhead fees and expenses), (ii)
         following the occurrence of an Event of Default under this Lease by
         Tenant (particularly if such Event of Default shall occur prior to the
         Commencement Date of this Lease), additional interest payable on, and
         other costs related to the delayed repayment of, the Construction Loan,
         additional costs to design, redesign and construct alternative interior
         tenant finish work (including costs, if any, to any general contractor
         or subcontractor to commence or recommence work in respect of the
         Building or any interior tenant finish) to the specifications of any
         replacement tenants who desire to lease any portion of the Building
         after an Event of Default hereunder in respect of Tenant, additional
         leasing commissions payable by Landlord in connection with the
         reletting of the



                                       18
<PAGE>   19



         Leased Premises (all of such development costs are referred to herein
         as "Landlord's Development Costs").

         (b) As an inducement for Landlord to agree to construct the Building,
         obtain the Construction Loan, and to enter into this Lease, Tenant has
         agreed that Tenant shall within ten (10) days after the Effective Date
         of this Lease deliver to Landlord the following collateral:

                  (1)      a cash deposit in the amount of $540,160 (the "Cash
                           Security Deposit"); and

                  (2)      a $9,000,000 irrevocable Letter of Credit addressed
                           to Landlord and Landlord's Mortgagee in the form of
                           Exhibit N attached hereto and incorporated herein by
                           reference or in such other form as may be reasonably
                           acceptable to Landlord and Landlord's Mortgagee and
                           issued by Wells Fargo Bank, N.A. or another financial
                           institution reasonably acceptable to Landlord and
                           Landlord's Mortgagee (the "Letter of Credit");

         the Cash Security Deposit and the Letter of Credit are hereafter
         referred to as the "Security". The Security shall secure the timely and
         prompt payment and performance by Tenant of:

                  (1)      its obligations under this Lease; and

                  (2)      its obligations under the Tri-Party Agreement set
                           forth on Exhibit L (the "Tri-Party Agreement")

         (c) Landlord agrees to deposit the Cash Security Deposit in a money
         market account yielding a market interest rate at a financial
         institution approved by Tenant, such approval not to be unreasonably
         withheld, with the interest accruing for the benefit of and payable to
         Tenant as it accrues on a monthly basis.

         (d) Tenant and Landlord hereby acknowledge and agree that the Security
         shall not be deemed an advance payment of Rent, liquidated damages, or
         a limitation on, or measurement of, Landlord's damages resulting from
         the occurrence of an Event of Default hereunder in respect of Tenant.
         If an Event of Default occurs hereunder in respect of Tenant, Landlord
         may, without prejudice to any other right or remedy hereunder, under
         the Tri-Party Agreement, at law or in equity, use the Security to the
         extent necessary to:

                  (1)      reimburse Landlord for the Landlord's Development
                           Costs which have been incurred or obligated to be
                           incurred by Landlord prior to the Event of Default;

                  (2)      pay any arrearages in Rent or any other sum owing by
                           Tenant under this Lease or the Tri-Party Agreement,
                           and



                                       19
<PAGE>   20



                  (3)      pay or reimburse Landlord for any other damage,
                           injury, expense, or liability of Landlord arising
                           from such Event of Default.

         Notwithstanding any provision herein to the contrary, however, it is
         agreed and understood that any sums utilized to reimburse Landlord for
         Landlord's Development Costs under item (1) above will be applied
         against and in reduction of any sums which are paid to or collected by
         Landlord under items (2) and/or (3) above. Any and all funds which are
         collected by or delivered to Landlord in connection with the Security
         and which are in excess of the total amount of the sums payable under
         items (2) and/or (3) above are referred to herein as "Excess Funds".
         Notwithstanding any provision herein to the contrary, it is agreed and
         understood that: (i) the Excess Funds will be maintained by Landlord in
         a separate account and will bear interest as provided in subparagraph
         3.05(c) above (except that interest will be retained in the account and
         will be added to the Excess Funds being held by Landlord until final
         disbursement, rather than being paid to Tenant monthly); (ii) no
         interest, late charges or other similar fees, charges or penalties will
         be levied or charged against Tenant under the terms of this Lease until
         and unless the Excess Funds have been fully depleted; and (iii)
         Landlord may retain the Excess Funds until a final determination has
         been made as to the sums payable to Landlord under items (2) and/or (3)
         above, but Landlord will refund all remaining Excess Funds to Tenant
         within ten (10) business days after the date of such final
         determination.

         (e) Landlord shall be permitted to make partial draws of the Letter of
         Credit. Landlord may, upon the occurrence of an uncured Event of
         Default (i) make a draw upon the Letter of Credit and/or (ii) apply all
         or part of the Cash Security Deposit and, in either case, apply the
         proceeds of such draw or the amount of such Cash Security Deposit, as
         applicable, to the payment of Rent and other amounts owing by Tenant
         under this Lease and the Tri-Party Agreement. If Landlord makes a
         partial draw or applies all or any portion of the Cash Security Deposit
         as provided herein, then Tenant shall promptly take all action as may
         be necessary to (i) restore the amount of the Letter of Credit to the
         letter of credit amount which is then required under the terms and
         provisions of Section 3.05(g) hereinbelow, and/or (ii) pay to Landlord
         the amount necessary to restore the Cash Security Deposit to its
         original amount. Landlord and Tenant recognize the Landlord's Mortgagee
         has required as a condition for the construction loan for the Building
         that Landlord and Tenant enter into the Tri-Party Agreement relating to
         the Letter of Credit.

         (f) If at any time during the term of this Lease:

                  (1)      an Event of Default occurs under the provisions of
                           Section 11.01(a)(2); or

                  (2)      an Event of Default occurs under the provisions of
                           Sections 11.01(a)(3) and/or 11.01(a)(4) and the
                           aggregate of the monetary defaults thereunder exceed
                           $1,000,000;

                  then Landlord may draw the full amount of the Letter of Credit
                  and apply such amount toward the payment of any amounts owed
                  under the Lease including



                                       20
<PAGE>   21



                  Landlord's Development Costs, to the extent but only to the
                  extent the same have been previously actually incurred or
                  obligated to be incurred by Landlord. If Landlord makes a draw
                  on the full amount of the Letter of Credit, Landlord shall be
                  required to notify Tenant of which election it has made under
                  Section 11.01(b) of this Lease, and Landlord will be subject
                  to the provisions of Section 3.05(d) hereinabove.

         (g) The Letter of Credit shall be automatically reduced on each
         anniversary of the Commencement Date to the amounts set out
         hereinbelow; except, however, that if an uncured Event of Default on
         the part of Tenant exists under this Lease, then the reduction will not
         occur until and unless Tenant has cured such Event of Default. The
         automatic reductions of the Letter of Credit are as follows:

<TABLE>
<CAPTION>
         ANNIVERSARY OF COMMENCEMENT DATE            LETTER OF CREDIT REDUCES TO
         -----------------------------------------------------------------------
<S>                                                  <C>
                           1st                                   $ 7,714,284
                           2nd                                     6,428,510
                           3rd                                     5,142,856
                           4th                                     3,857,142
                           5th                                     2,571,428
                           6th                                     1,285,714
                           7th                                        -0-
</TABLE>


         If at any time during the term hereof, Tenant provides Landlord with
         notice that Tenant has attained a Standard & Poors Bond Rating of "BB"
         or better, Landlord shall promptly reduce Tenant's obligation as to the
         Letter of Credit by fifty percent (50%) for so long as Tenant's rating
         remains at "BB" or better. The fifty percent (50%) reduction (the "LOC
         Reduction") hereunder is in addition to the automatic annual reductions
         provided for hereinabove. If Tenant obtains the credit rating specified
         above, then the initial amount of the Letter of Credit and each of the
         amounts set out in the column hereinabove relating to the remaining
         amount of the Letter of Credit after each annual reduction will be
         reduced by fifty percent (50%). If at any time after the LOC Reduction
         is effective should Tenant's bond rating be revised to less than a
         "BB", Tenant shall immediately post a Letter of Credit (by amendment of
         the existing Letter of Credit or an additional Letter of Credit) to
         increase the amount in accordance with the above schedule.
         Notwithstanding any provision herein to the contrary, it is agreed and
         understood that Tenant will have no obligation to maintain the Letter
         of Credit from and after the date which is exactly seven (7) years
         after the Commencement Date; except, however, that if an uncured Event
         of Default on the part of Tenant exists at such time, then the Letter
         of Credit will be released only if and after Tenant has cured such
         Event of Default.

         (h) The Letter of Credit may be reduced or replaced from time to time
         to effectuate the changes in amount which are provided for under this
         Lease. If at any time during the term of the Lease in which the Letter
         of Credit is continuing as Security under the Lease, Landlord is
         notified that the issuing bank of the Letter of Credit has elected not
         to renew the Letter of Credit, Tenant shall have until the date which
         is thirty (30) days prior to the then current expiration date of the
         Letter of Credit to provide a replacement Letter of Credit reasonably
         acceptable to Landlord. If Tenant fails to provide a replacement Letter



                                       21
<PAGE>   22



         of Credit, reasonably satisfactory to Landlord, then Landlord may draw
         the full amount of the Letter of Credit and apply the proceeds to the
         amounts specified in, and subject to the limitations and provisions of
         Section 3.05(d), the remaining funds will be held with the Cash
         Security Deposit pursuant to Section 3.05(c) above. Notwithstanding any
         provision herein to the contrary, however, it is agreed and understood
         that if Landlord draws upon the Letter of Credit under the terms of
         this Section 3.05(h) and Tenant subsequently delivers to Landlord a new
         Letter of Credit which satisfies the requirements under this Lease
         then, so long as no uncured Event of Default in respect of Tenant
         exists at such time, Landlord will simultaneously with Tenant's
         delivery of the new Letter of Credit, return to Tenant all sums which
         were previously drawn by Landlord under the old Letter of Credit.

         (i) Landlord shall return (i) the original, unexpired Letter of Credit,
         and (ii) the remaining balance of the Cash Security Deposit, if any, to
         Tenant upon the termination or expiration of this Lease (except in the
         case of an Event of Default) and after surrender by Tenant of
         possession of the Leased Premises to Landlord in accordance with this
         Lease.

         (j) If Landlord assigns its interest in the Leased Premises, Landlord
         may assign the Security to the assignee. Landlord will then have no
         further liability for the return of the Security after the assignment
         and Tenant shall look solely to the assignee for the return of the
         Security. Tenant may not assign or encumber or attempt to assign
         (except in connection with a permitted assignment of this Lease by
         Tenant or a collateral assignment to a lender) Tenant's interest in the
         Security. Landlord and its successors and assigns are not bound by any
         actual or attempted assignment (except in connection with a permitted
         assignment of this Lease by Tenant or a collateral assignment to a
         lender) of Tenant's interest in the Security.

         (k) Notwithstanding any provision herein to the contrary, it is agreed
         and understood that possession and control of the Letter of Credit,
         including all funds drawn under the Letter of Credit, will be held by
         Landlord's Mortgagee (hereinafter defined).

                       ARTICLE IV - UTILITIES AND SERVICES

Section 4.01 Services to be Provided

         Provided no uncured Event of Default on the part of Tenant exists,
         Landlord shall furnish or cause to be furnished to the Leased Premises,
         the utilities and services described below, subject to the conditions
         and in accordance with the standards set forth herein:

         (a) Landlord shall provide automatic elevator service to the Leased
         Premises twenty-four (24) hours per day, seven (7) days per week.

         (b) During Building Standard Hours, Landlord agrees to ventilate the
         Leased Premises and furnish heat or air conditioning, at such
         temperatures and in such amounts as is necessary and appropriate for
         the comfortable occupancy of the Leased Premises, reasonably consistent
         with the standards of "Class A" office buildings in Austin, Texas and
         in accordance with Tenant's instructions. With respect to the Building
         (i) so long as Tenant is the sole Tenant of the Building, Tenant shall
         have the right to modify Building



                                       22
<PAGE>   23



         Standard Hours at any time and from time to time by delivering written
         notice of such modification to Landlord; and (ii) Tenant shall be
         provided after hours service through an automated "on-demand" system,
         which will allow Tenant to directly control the heating and air
         conditioning system. Tenant shall reimburse Landlord for the actual
         costs incurred by Landlord for all additional heating or air
         conditioning. Upon request, Landlord will provide Tenant with a
         calculation of the basis for Landlord's then current charges for
         additional heating and air conditioning.

         (c) Electric lighting for the Building.

         (d) Toilet facilities and hot and cold water for lavatory and drinking
         purposes (at temperatures prescribed by applicable law or as
         customarily provided in other Class A buildings in Austin, Texas).

         (e) Replacement, as necessary, of all lamps and ballasts in the
         building standard light fixtures within the Leased Premises.

         (f) Window washing of exterior windows not less than once each year.

         (g) Professional landscaping services periodically as necessary to
         maintain all landscaped areas from time to time on the Land.

         (h) Janitorial services five (5) days per week, during hours designated
         by Tenant from time to time (provided such designations do not increase
         normal and customary costs for such services) reasonably consistent in
         quality to those being provided by other Class A office buildings in
         Austin, Texas.

         (i) A building engineer located within the Terrace P.U.D. with
         "on-call" hours consistent with other Class A office buildings in
         Austin, Texas.

         (j) Competent property management for the Building located within the
         Terrace P.U.D.

         (k) Landlord shall furnish electrical service to the Leased Premises in
         accordance with Exhibit C at all times, subject to interruptions beyond
         Landlord's control and temporary interruptions necessary or appropriate
         for Building maintenance or equipment installation. In no event may
         Tenant's use of electricity exceed the capacity of the feeders to the
         Building or the risers or wiring installation. Electrical consumption
         in the Leased Premises, or in any portion of the Leased Premises in
         which excess electricity is consumed, may, at Landlord's option, be
         separately metered. Tenant shall pay on demand all costs associated
         with any separate metering required by Landlord, including but not
         limited to installation of any separate metering devices and the costs
         of all electrical consumption in any areas which are separately
         metered. The obligation of Landlord to provide or cause to be provided
         electricity is subject to the rules and regulations of the supplier of
         electricity and of any municipal or other governmental authority
         regulating the business of providing electricity, except as provided in
         Section 4.04. Except as expressly provided in this Lease, Landlord is
         not liable or responsible to Tenant for any loss, damage



                                       23
<PAGE>   24



         or expense Tenant sustains or incurs if either the quality or character
         of the electricity is changed or is no longer available or no longer
         suitable for Tenant's requirements.

         At any time when Landlord is furnishing electricity to the Leased
         Premises under this subsection, Landlord may, at its option, upon not
         less than thirty (30) days prior written notice to Tenant, discontinue
         the furnishing of electricity, provided adequate provisions have been
         made for a transfer of service so that no interruption of electrical
         service will occur. If Landlord gives a notice of discontinuance,
         Landlord shall make all reasonably necessary arrangements with the
         public utility supplying the electricity to the Building with respect
         to connecting electrical service to the Leased Premises, but Tenant
         shall contract directly with the public utility with respect to
         supplying the electrical service.

         (l) If not included in the Tenant Finish Work, at Tenant's option and
         election after the Commencement Date: (i) Landlord, at Tenant's sole
         cost and expense, will install and maintain a card-key access control
         system for entry into the Building and for elevator operation during
         non-Business Standard Hours for the use of Tenant, which system must be
         approved by Tenant and must be compatible with the security system
         installed by Tenant within the Leased Premises; or (ii) Tenant may, at
         Tenant's sole cost and expense, install its own card-key access control
         system for entry into the Building and for elevator operation during
         non-Business Standard Hours. Further, Landlord will provide 24-hour per
         day, 7 days per week security service for the Building. Provided Tenant
         is the sole Tenant of the Building, Tenant may at Tenant's option and
         election, replace Landlord's security service with a security service
         or security personnel retained by Tenant (and in such event, no costs
         for security services will be included by Landlord in the Operating
         Expenses). In all events, Tenant will have the right to install its own
         security system equipment in the Leased Premises, and all such security
         system equipment will remain Tenant's property and may be removed by
         Tenant upon termination of the Lease.

Section 4.02 Tenant's Obligations

         Tenant shall cooperate fully at all times with Landlord and abide by
         all regulations and requirements Landlord may prescribe for the use of
         all utilities and services that are consistent with the terms of this
         Lease.

Section 4.03 Service Interruptions

         (a) Landlord does not warrant that the services provided by Landlord
         will be free from any slow-down, interruption, or stoppage by
         governmental bodies, regulatory agencies, utility companies, and others
         supplying services or caused by the maintenance, repair, replacement,
         or improvement of any equipment involved in the furnishing of the
         services or caused by changes of services, alterations, strikes,
         lock-outs, labor controversies, fuel shortages, accidents, acts of God,
         the elements, or other causes beyond the reasonable control of
         Landlord.

         (b) Landlord shall use diligent and reasonable efforts to restore any
         service that becomes unavailable; however such unavailability shall not
         render Landlord liable for any damages caused thereby, be a
         constructive eviction of Tenant, constitute a breach of any implied
         warranty, or, except as provided in the next sentence, entitle Tenant
         to any



                                       24
<PAGE>   25



         abatement of Tenant's obligations hereunder unless such unavailability
         is caused by Landlord's gross negligence or intentional misconduct.
         However, if because of the unavailability of any such service Tenant is
         prevented from making reasonable use of a material portion of the
         Leased Premises for more than five (5) consecutive business days, then
         Tenant's obligation to pay Base Rent and Additional Rent in respect of
         the portion of the Leased Premises rendered untenantable thereby shall
         be abated for each consecutive day after such five (5) business day
         period that Tenant is so prevented from making reasonable use of such
         portion of the Leased Premises. If any such unavailability or
         interruption of services occurs (other than because of a taking or
         Casualty [defined below] as to which Article VIII and Section 7.03
         shall control), and Landlord fails to restore such services to the
         Leased Premises within fifteen (15) days following delivery of written
         notice from Tenant to Landlord, Tenant may commence to restore such
         services unless Landlord is diligently performing the work that may be
         necessary to restore such services. All actual third-party costs
         incurred by Tenant in connection with restoring such services shall be
         paid by Landlord to Tenant within thirty (30) days following written
         demand therefor to Landlord (accompanied by invoices substantiating
         such claim) plus interest at the Interest Rate from the date of payment
         of such cost by Tenant until paid by Landlord. Tenant's right to
         perform work under this Section 4.03(b) is subject to the following
         conditions:

                  (1) all such work shall be performed in a good and workmanlike
                  manner and in accordance with law;

                  (2) except in an emergency or in the event of work which
                  consists solely of the repair and/or replacement of existing
                  facilities, all such work shall be performed in accordance
                  with plans and specifications approved by Landlord (which
                  approval shall not be unreasonably withheld), whose approval
                  shall be deemed given if Landlord fails to disapprove any
                  submitted plans and specifications within three business days
                  after Tenant delivers such plans to Landlord;

                  (3) all such work shall be performed by contractors reasonably
                  acceptable to Landlord which maintain commercial liability
                  insurance in an amount not less than $1,000,000 per occurrence
                  naming Landlord as an additional insured; Landlord's approval
                  shall be deemed given if Landlord fails to disapprove any
                  contractor within three business days after Tenant delivers to
                  Landlord a request for its consent thereto; and

                  (4) except in an emergency or in the event of work which
                  consists solely of the repair and/or replacement of existing
                  facilities, Tenant delivers to Landlord "as-built" plans of
                  the work performed by Tenant.

Section 4.04 Modification

         Landlord reserves the right from time to time to make reasonable and
         nondiscriminatory modifications to the above standards for utilities
         and services by giving written notice to Tenant.



                                       25
<PAGE>   26



                          ARTICLE V - USE AND OCCUPANCY

Section 5.01 Use and Occupancy

         (a) The Leased Premises may be used and occupied for the Permitted Use
         specified in the Basic Lease Provisions and for any other uses allowed
         under Applicable Laws (hereinafter defined). Tenant shall use and
         maintain the Leased Premises in an operable, attractive condition
         (ordinary wear and tear and damage by casualty and condemnation
         excepted) and shall comply with all laws, ordinances, orders, rules,
         regulations and requirements of any kind imposed by any governmental
         authority (state, federal, county and municipal) applicable to or
         having jurisdiction over the use, occupancy, operation, and maintenance
         of the Leased Premises, including without limitation, all applicable
         environmental laws and the Americans With Disabilities Act of 1990
         (ADA) (those laws, ordinances, orders, rules, decisions, and
         regulations hereafter referred to as "Applicable Law" or "Applicable
         Laws"). Landlord shall construct the Building and the Leased Premises
         in accordance with all Applicable Laws; shall operate and maintain the
         Building in compliance with all Applicable Laws; and shall otherwise
         comply with all Applicable Laws relating to access to the Building and
         the Leased Premises.

         (b) Tenant may not deface or injure the Leased Premises or the Building
         or any part thereof or overload the floors of the Leased Premises
         (beyond the capacities for which such floors are required to be
         designed under the terms and provisions of this Lease). Tenant may not
         commit waste or permit waste to be committed or cause or permit any
         nuisance on or in the Leased Premises or the Building. Tenant shall pay
         Landlord on demand as Rent for any damages to the Leased Premises or to
         any other part of the Building which is not covered by insurance which
         Landlord is required to carry under the terms of this Lease and which
         is caused by any negligence or willful act or any misuse or abuse
         (whether or not the misuse or abuse results from negligence or willful
         acts) by Tenant or notwithstanding any provision herein to the
         contrary, Tenant shall have no liability to Landlord for any damage or
         liability which is or should be covered by the insurance which Landlord
         is required to maintain under the terms and provisions of this Lease.

         (c) Tenant's agents, employees, licensees, invitees or contractors
         (hereafter referred to as "Tenant Party" or "Tenant Parties") shall not
         erect, place, or allow to be placed any sign, symbol, advertising
         matter, stand, booth, or showcase in or upon the doorsteps, vestibules,
         halls, corridors, doors, walls, windows, or pavement of the Building
         visible outside the Leased Premises (except for lettering on the door
         or doors to the Leased Premises as allowed by the Rules and Regulations
         attached hereto as Exhibit D) without the prior consent of Landlord
         which will not be unreasonably withheld.

         (d) Tenant may not use or allow or permit the Leased Premises to be
         used in any way or for any purpose that:

                  (1) is extra-hazardous on account of the possibility of fire
                  or other casualty;

                  (2) renders the Building uninsurable at normal rates by
                  responsible insurance carriers authorized to do business in
                  the State of Texas or renders void or voidable any insurance
                  on the Building.



                                       26
<PAGE>   27



         If insurance premiums are increased because of Tenant's use of the
         Leased Premises, then, in addition to any other remedies Landlord may
         have, Tenant shall pay the amount of the increase to Landlord as Rent
         within five (5) days after demand.

Section 5.02 Rules and Regulations

         Tenant and each Tenant Party shall comply with the rules and
         regulations attached as Exhibit D (the "Rules and Regulations"). Tenant
         is responsible for the compliance with the Rules and Regulations by
         each Tenant Party.

Section 5.03 Quiet Enjoyment

         If Tenant pays the Rent when due and timely performs all other
         obligations of Tenant under this Lease, then Tenant may peaceably and
         quietly enjoy the Leased Premises during the Lease Term without any
         disturbance from Landlord or from any other person claiming by,
         through, or under Landlord, subject to the terms of this Lease and of
         the deeds of trust, mortgages, ordinances, utility easements,
         agreements and other matters to which this Lease may be subordinate.

                ARTICLE VI - REPAIRS, MAINTENANCE AND ALTERATIONS

Section 6.01 Repair and Maintenance by Tenant

         (a) Tenant shall keep the Leased Premises and all fixtures installed by
         or on behalf of Tenant in good and tenantable condition (ordinary wear
         and tear and damage by casualty and condemnation excepted). Tenant
         shall promptly make all necessary non-structural repairs and
         replacements thereto at Tenant's expense. All repairs and replacements
         must be at least equal in quality to the original work, and all
         contractors and subcontractors performing such repairs and replacements
         must comply with the conditions specified in Section 6.02(a)
         hereinbelow. Without diminishing this obligation of Tenant, if Tenant
         fails to commence to make any repairs and replacements which are
         required of Tenant hereunder within fifteen (15) days after notice from
         Landlord and thereafter diligently pursue such repairs or replacements,
         Landlord may at its option make the repairs and replacements and Tenant
         shall pay Landlord on demand as Rent the costs incurred by Landlord
         plus an administrative fee equal to ten (10%) percent of the costs plus
         interest at the Interest Rate from the date of payment of such cost by
         Landlord until paid by Tenant.

         (b) Tenant shall pay the cost of repairs and replacements due to damage
         or injury to the Building or any part thereof caused by any Tenant
         Party or by any malfunction or misuse of any equipment installed by or
         on behalf of Tenant. This amount is payable by Tenant to Landlord on
         demand as Rent plus interest at the Interest Rate from the date of
         payment by Landlord until paid by Tenant. Notwithstanding any provision
         herein to the contrary, however, Tenant shall not be required to pay
         any cost or expense related to any damage or injury which is or should
         be covered by insurance which Landlord is required to maintain under
         the terms and provisions of this Lease. If Tenant requests Landlord to
         perform any maintenance or repairs to the Leased Premises, over and
         above the services required to be performed by Landlord pursuant to
         Article IV, Tenant shall pay the actual



                                       27
<PAGE>   28



         cost thereof, plus a reasonable administrative fee not to exceed ten
         (10%) percent of the actual cost thereof, to Landlord as Rent within
         ten (10) business days after demand.

Section 6.02 Alterations and Additions by Tenant

         (a) Tenant may not make or permit any alterations, improvements or
         additions in or to the Leased Premises or the Building without
         Landlord's prior written consent, such consent not to be unreasonably
         withheld; provided however, that: (i) Tenant shall not be required to
         obtain Landlord's approval for alterations which cost less than $30,000
         each and do not materially affect the structure of the Building or its
         HVAC, electrical or plumbing systems; and (ii) nothing in this Lease
         will require Tenant to obtain Landlord's consent for interior painting,
         carpeting and similar decorative modifications to the Leased Premises,
         regardless of the costs thereof. All alterations, additions and
         improvements made to, or fixtures or other improvements placed in or
         upon, the Leased Premises, whether temporary or permanent in character,
         by either party (except only Tenant's fixtures, and all of Tenant's
         office furniture, equipment and other movable items of personal
         property) are a part of the Building and are the property of Landlord
         when they are placed in the Leased Premises unless otherwise agreed by
         Landlord and Tenant. Except for alterations, improvements and additions
         which Tenant is allowed to make without necessity of obtaining
         Landlord's approval, all alterations, improvements and additions in and
         to the Leased Premises requested by Tenant must be made in accordance
         with plans and specifications approved in advance in writing by
         Landlord. All work must be performed at Tenant's expense either by
         Landlord or by contractors and subcontractors approved in advance by
         Landlord. If the work is not performed by Landlord, then all work
         performed by Tenant's contractors and subcontractors is subject to the
         following conditions:

                  (1) Each contractor and subcontractor must deliver evidence
                  satisfactory to Landlord that the insurance specified in
                  Exhibit E is in force prior to commencing work.

                  (2) Tenant shall use good faith efforts to insure that all
                  workers are cooperative with Building personnel and comply
                  with all Building Rules and Regulations.

                  (3) Tenant must deliver to Landlord evidence that Tenant has
                  obtained all necessary governmental permits and approvals for
                  the improvements or alterations prior to starting any work.

                  (4) All construction must be done in a good and workmanlike
                  manner and is subject to approval by Landlord during and after
                  construction, in its reasonable discretion.

                  (5) Lien releases from each contractor (subject to final
                  retainage payments) must be submitted to Landlord within ten
                  (10) business days after completion of the work performed by
                  the contractor.



                                       28
<PAGE>   29



                  (6) Within thirty (30) days after completion of any
                  improvements or alterations, Tenant, at its cost, shall
                  deliver to Landlord, on CAD disks, copies of "as-built" plans
                  and specifications (1/8" scale) for each floor where material
                  alterations or improvements were made.

         (b) All alterations and improvements must comply with all Applicable
         Laws. Neither Landlord's approval of Tenant's plans and specifications
         for the alterations or improvements, nor Landlord's acceptance of
         Tenant's as-built plans is a confirmation or agreement by Landlord that
         the improvements and alterations comply with Applicable Laws.

Section 6.03 Mechanics' Liens - Tenant's Obligations

         If any mechanic's or materialman's lien is placed upon Landlord's
         interest in the Building or the Leased Premises or any part thereof or
         against Landlord's interest under this Lease by any architect,
         contractor, subcontractor, laborer, or materialman performing any labor
         or furnishing any materials to Tenant for any improvement, alteration,
         or repair of or to the Leased Premises, the Building, or any part
         thereof, Tenant shall either: (i) cause the same to be discharged of
         record within twenty (20) days after filing; or (ii) post a bond or
         other security reasonably acceptable to Landlord to cover the full
         amount of the claim. If Tenant does not satisfy one or the other of the
         foregoing requirements, then Landlord may, but is not obligated to,
         discharge the lien by paying the amount claimed to be due or by
         procuring the discharge of the lien by deposit in court or bonding. Any
         amount paid by Landlord relating to any lien not caused by Landlord,
         and all reasonable legal and other expenses of Landlord, including
         reasonable attorneys' fees, in defending any action or in procuring the
         discharge of any lien, with interest thereon at the Interest Rate from
         date of payment by Landlord until paid by Tenant, is payable by Tenant
         to Landlord on demand as Rent.

Section 6.04 Maintenance and Repair by Landlord

         Landlord shall maintain the Building in first-class condition and
         repair and shall operate the Building as a first-class office building,
         similar to other Class A buildings in Austin, Texas. Landlord shall not
         permit or allow to remain any waste or damage to any portion of the
         Building. Without limitation on the generality of the foregoing,
         Landlord represents and warrants to Tenant that the Building's
         structure and operational systems will be in good condition and
         suitable for Tenant's Permitted Use from and after the Commencement
         Date. Subject to reimbursement of the Operating Expenses, Landlord will
         maintain in good repair and condition all (i) service areas; (ii)
         roofs, ceilings, foundations, floorslabs, parking areas, pavement,
         exterior windows and load bearing items; (iii) exterior surfaces of
         walls; (iv) plumbing, pipes and conduits located in the service areas;
         (v) central heating, ventilation and air conditioning, electrical,
         mechanical and plumbing systems, including, but not limited to, those
         servicing the Leased Premises (other than excess electrical equipment
         and other supplemental equipment installed by or for Tenant); (vi)
         structural and mechanical elements, including without limitation, those
         related to the Leased Premises necessary to provide the services
         described in Article IV; (vii) parking garages; (viii) elevators; (ix)
         surface parking lots, driveways, sidewalks, landscaping and other
         improvements or additions to the Land; and (x) Building security



                                       29
<PAGE>   30



         and life safety systems. Landlord will at all times maintain the
         Building in accordance with standards as customarily followed in the
         operation and maintenance of Class A office buildings in Austin, Texas.

                   ARTICLE VII - INSURANCE, FIRE AND CASUALTY

Section 7.01 Tenant's Insurance

         (a) Tenant shall, at its expense, maintain at all times a policy or
         policies of insurance insuring Tenant against all liability for injury
         to or death of a person or persons and for damage to or destruction of
         property occasioned by or arising out of or in connection with the use
         or occupancy of the Leased Premises or by the condition of the Leased
         Premises (including Tenant's contractual liability to indemnify and
         defend Landlord) with a combined single limit of $2,000,000 for bodily
         injury and property damages, or with increased limits as may be
         reasonably required from time to time by Landlord by giving notice to
         Tenant not to exceed a combined single limit in excess of $5,000,000.
         Tenant's policies must be written by an insurance company or companies
         reasonably satisfactory to Landlord and licensed to do business in the
         State of Texas with Landlord and Landlord's manager named as additional
         insureds. Tenant shall obtain a written obligation on the part of each
         insurance company to notify Landlord at least fifteen (15) days prior
         to cancellation of the insurance.

         (b) Tenant shall deliver duly executed certificates of insurance to
         Landlord prior to occupying any part of the Leased Premises. Tenant
         shall deliver satisfactory evidence of renewals of the insurance
         policies to Landlord within ten (10) days of the expiration of the
         respective policies. If Tenant fails to comply with these insurance
         requirements, Landlord may obtain the insurance and Tenant shall pay to
         Landlord on demand as additional Rent the premium cost thereof plus
         interest at the Interest Rate from the date of payment by Landlord
         until paid by Tenant.

         (c) Tenant shall insure that all contractors, subcontractors, moving
         companies and others performing work of any type for Tenant in the
         Building shall comply with the insurance requirements set out on
         Exhibit E attached hereto and incorporated herein by reference, as such
         insurance requirements may be reasonably revised from time to time by
         Landlord (acting reasonably and in accordance with practices which are
         comparable to practices utilized at other Class A buildings in Austin,
         Texas). Landlord shall inform Tenant in writing of all revisions to the
         insurance requirements.

Section 7.02 Landlord's Insurance

         Landlord shall, at all times during the Lease Term, maintain insurance
         insuring the Building at its full replacement cost, and also insuring
         any loss of rents by Landlord due to any loss or damage by fire,
         explosion or other hazards or contingencies. Such insurance will be
         provided through a policy or policies with deductible amounts which are
         approved in writing by Tenant and otherwise with terms, coverages and
         conditions as are normally carried by reasonably prudent owners of
         properties similar to the Building. The company or companies writing
         any insurance which Landlord is required to maintain under this Lease
         must be licensed to do business in the State of Texas and must have an
         A.M. Best



                                       30
<PAGE>   31



         rating of AVI or better. Tenant agrees that all personal property upon
         the Leased Premises shall be at the risk of Tenant only and that
         Landlord shall not be liable for any damage thereto or theft thereof.
         If by reason of any act or conduct of business of Tenant there shall be
         any increase in the rate of insurance on the Building or contents
         created by Tenant's acts or conduct of business, Tenant agrees to pay
         Landlord the amount of such increase on demand.

Section 7.03 Fire or Other Casualty

         (a) If the Leased Premises or any part thereof are damaged by fire or
         other casualty (a "Casualty"), Tenant shall give prompt notice thereof
         to Landlord. If the Leased Premises or the Building is damaged by a
         Casualty, Landlord shall, within thirty (30) days after such Casualty
         deliver to Tenant a good faith estimate (the "Damage Notice") of the
         date on which the repair of the damage caused by such Casualty will be
         substantially completed (such date is herein called the "Estimated
         Restoration Completion Date"). Base Rent and Additional Rent shall
         abate to a fair and equitable extent as of the date of the Casualty
         with respect to the portion of the Leased Premises and/or the Building
         affected by the Casualty until substantial completion of repairs to the
         Leased Premises and elevator access and other services are available to
         the Leased Premises for conduct of Tenant's business.

         (b) If the Leased Premises or the Building is damaged by Casualty such
         that Tenant is prevented from conducting its business in a material
         portion of the Leased Premises in a manner reasonably comparable to
         that conducted immediately before such Casualty, then:

                  (i) if the Estimated Restoration Completion Date is later than
                  one hundred eighty (180) days after the date of the Casualty,
                  Tenant may terminate this Lease by delivering written notice
                  to Landlord of its election to terminate within thirty (30)
                  days after the Damage Notice has been delivered to Tenant or,
                  if no such notice is delivered by Landlord, within ninety (90)
                  days after the Casualty; and

                  (ii) if Tenant does not, or does not have the right to,
                  terminate this Lease pursuant to this Section 7.03(b) and such
                  damage is not repaired by the Casualty Restoration Termination
                  Date (defined below), Tenant may terminate this Lease by
                  delivering written notice to Landlord of its election to
                  terminate before the earlier of (A) thirty (30) days after the
                  Casualty Restoration Termination Date (defined below) or (B)
                  the completion of such repairs.

         Any termination right of Tenant not timely exercised shall be deemed
         waived, time being of the essence with respect thereto. In case of any
         termination under Section 7.03(b)(i) above, Base Rent and Additional
         Rent shall abate in full as of the date of the Casualty. In case of any
         termination under Section 7.03(b)(ii) above, the portion of the Base
         Rent for the portion of the Leased Premises affected thereby not
         theretofore abated shall abate as of the date of termination. Unless
         Landlord and Tenant agree in writing otherwise, the "Casualty
         Restoration Termination Date" shall be thirty (30) days after the later
         of (1) one hundred eighty (180) days after the Casualty, or (2) the
         Estimated Restoration Completion Date.

         (c) If Tenant does not elect to terminate this Lease following a
         Casualty, then Landlord shall, within a reasonable time after such
         Casualty, subject to approval from



                                       31
<PAGE>   32



         Landlord's Mortgagee, commence to repair the Building and the Leased
         Premises and shall proceed with reasonable diligence to restore the
         Building and Leased Premises to substantially the same condition as
         they existed immediately before such Casualty; however, Landlord shall
         not be required to repair or replace any part of the furniture,
         equipment, fixtures, and other improvements which may have been placed
         by, or at the request of, Tenant or other occupants in the Building or
         the Leased Premises.

         (d) If the damages are caused by the willful misconduct of Tenant or
         any Tenant Party, Tenant shall pay to Landlord on demand as Additional
         Rent any damages in excess of the amount paid by insurance proceeds
         received by Landlord which are not covered by the insurance which
         Landlord is required to carry under the terms and provisions of this
         Lease. Any insurance carried by Landlord or Tenant against loss or
         damage to the Building or to the Leased Premises is for the sole
         benefit of the party carrying the insurance and under its sole control.

         (e) If Tenant does not elect to terminate the Lease pursuant to Section
         7.03(b) above and Landlord's Mortgagee requires that the insurance
         proceeds due Landlord for the Casualty are to be applied to the
         Building Mortgage, then in such event, Landlord will use reasonable
         efforts to acquire replacement financing in order to restore the
         Building. Landlord and Tenant acknowledge that in such event it is not
         possible to predict market conditions in advance. In such event,
         Landlord hereby grants Tenant a Right of First Offer (the "Tenant's
         First Offer Right") as hereafter described:

                  (i)      If Landlord is able to acquire replacement financing
                           to rebuild the Building, then in such event, Landlord
                           shall, prior to offering the Building for lease or
                           sale to a third party, give Tenant not less than
                           thirty (30) days within which to accept a proposal
                           for the sale or lease of the Building.

                  (ii)     If Landlord is not able to acquire replacement
                           financing and determines to sell the Land, then in
                           such event, Landlord shall, prior to offering the
                           Land for sale to a third party, give Tenant a
                           proposal for Tenant to purchase the Land and Tenant
                           shall have thirty (30) days within which to accept
                           the proposal for the purchase of the Land.

         Landlord and Tenant agree if Landlord shall offer the Tenant's First
         Offer Right, Landlord and Tenant will meet, if required, to reach a
         market rate rent or purchase price. If an agreement cannot be reached
         after good faith discussions between Landlord and Tenant within said
         thirty (30) day period, neither party shall have any further obligation
         hereunder.

Section 7.04 Waiver of Subrogation

         Each party waives all claims that arise or may arise in its favor
         against the other party, or anyone claiming through or under them, by
         way of subrogation or otherwise, during the Lease Term or any extension
         or renewal thereof, for any injury to or death of any person or persons
         or the theft, destruction, loss of, or damage to, any of its property
         (a "Loss") caused by casualty, theft, fire, third parties, or any other
         matter, to the extent the same is insured against by it under any
         insurance policy that covers the Building, the Leased



                                       32
<PAGE>   33



         Premises, Landlord's or Tenant's fixtures, personal property, leasehold
         improvements, or business, or is required to be insured against by it
         under the terms hereof (whether or not the loss or damage is caused by
         the fault or negligence of the other party or anyone for whom the other
         party is responsible). These waivers are in addition to, and not in
         limitation of, any other waiver or release in this Lease with respect
         to any Loss. Since these mutual waivers preclude the assignment of any
         claim by way of subrogation (or otherwise) to an insurance company (or
         any other person), each party shall immediately give each insurance
         company issuing to it policies of fire and extended coverage insurance
         written notice of the terms of these mutual waivers, and have the
         insurance policies properly endorsed, if necessary, to prevent the
         invalidation of the insurance coverages by reason of these waivers.

                           ARTICLE VIII - CONDEMNATION

         (a) If all or substantially all of the Building is taken for any public
         or quasi-public use under any governmental law, ordinance or regulation
         or by right of eminent domain or is sold to the condemning authority in
         lieu of condemnation, then this Lease will terminate as of the date
         when physical possession of the portion of the Building is taken by the
         condemning authority. If less than all or substantially all of the
         Building is taken or sold, and if such taking or sale prevents Tenant
         from conducting its business in the Leased Premises in a manner
         reasonably comparable to that conducted immediately before such taking,
         then Tenant may terminate this Lease as of the date of such taking or
         sale by giving Landlord written notice within sixty (60) days after the
         taking, and Rent shall be apportioned as of the date of such taking.

         (b) If this Lease is not terminated by Tenant upon any taking or sale
         of less than all or substantially all of the Building and Tenant does
         not terminate this Lease as provided below:

                  (1) The Rent will be reduced by a fair and equitable amount
                  representing that part of the Rent properly allocable to the
                  portion of the Leased Premises or the Building which is taken
                  or sold, if any; and

                  (2) Landlord shall, at Landlord's sole expense, restore the
                  Building to substantially its former condition to the extent
                  reasonably deemed feasible by Landlord, but:

                           (A) Landlord's restoration obligation does not exceed
                           the scope of the work done by Landlord in originally
                           constructing the Building and installing Tenant
                           Finish Work in the Leased Premises; and

                           (B) Landlord is not required to spend for the work an
                           amount in excess of the amount received by Landlord
                           as compensation or damages (over and above amounts
                           going to the mortgagee of the property taken) for the
                           part of the Building so taken.

         (c) Tenant shall be entitled to receive, out of the compensation
         awarded upon a taking of any part of the Building, an amount equal to
         any unamortized Tenant expenditures for



                                       33
<PAGE>   34



         build-out costs incurred by Tenant in excess of the Allowance. In this
         regard, all amortizations of Tenant expenditures will be done on a
         straight line basis over the Lease Term. In addition, Tenant shall be
         entitled to separately pursue claims against the condemner for the
         value of Tenant's personal property, moving costs, loss of business and
         other reasonable claims it may have. Except as provided above, Landlord
         will be entitled to receive all of the compensation awarded upon a
         taking of all or any part of the Building, including any award for the
         value of the unexpired Lease Term.

                    ARTICLE IX - INDEMNIFICATIONS AND WAIVERS

Section 9.01 Limitations on Liability of Landlord and Waivers

         Landlord is not liable to any Tenant or any Tenant Party or any other
         person, and Tenant waives any liability of Landlord, for:

                  (1) any injury or damage to person or property due to the
                      condition or design of, or any defect in the Building that
                      exists now or occurs in the future, except for Landlord's
                      or any of Landlord's agents or contractors' gross
                      negligence or willful misconduct;

                  (2) any injury or damage to person or property due to the
                      Building or related improvements or appurtenances being
                      out of repair, or defects in or failure of pipes or
                      wiring, or backing up of drains, or the bursting or
                      leaking of pipes, faucets and plumbing mixtures, or gas,
                      water, stream, electricity, or oil leaking, escaping, or
                      flowing into the Leased Premises unless caused by
                      Landlord's willful misconduct or gross negligence;

                  (3) any loss or damage caused by the acts or omissions of
                      other tenants in the Building or of any other persons,
                      excepting only the willful misconduct or gross negligence
                      of Landlord; or

                  (4) any loss or damage to property or person occasioned by
                      theft, fire, act of God, public enemy, injunction, riot,
                      insurrection, war, court order, requisition, order of
                      government authority, and any other cause beyond the
                      control of Landlord.

Section 9.02 No Implied Waiver

         The failure of either party to insist at any time upon the strict
         performance of any of the terms of this Lease or to exercise any
         option, right, power or remedy contained in this Lease is not a waiver
         of the right or remedy for the future. The waiver of any breach of this
         Lease or violation of the Rules and Regulations attached hereto does
         not prevent a subsequent act, which would have originally constituted a
         breach or violation, from having all the force and effect of an
         original breach or violation. No express waiver affects any terms other
         than the ones specified in the waiver and those only for the time and
         in the manner specifically stated. Acceptance by Landlord of any Rent
         after the breach of any of the terms of this Lease or violation of any
         Rule or Regulation is not a waiver of the breach or violation or the
         right to collect applicable late charges and interest, and no waiver by



                                       34
<PAGE>   35



         either party of any of the terms of this Lease is effective unless
         expressed in writing and signed by such party.

Section 9.03 Waiver by Tenant

         Tenant waives and surrenders for itself and all persons or entities
         claiming by, through, and under it, including creditors of all kinds:
         (A) any right and privilege which it or any of them has under any
         present or future constitution, statute, or rule of law to redeem the
         Leased Premises or to have a continuance of this Lease for the Lease
         Term after termination of Tenant's right of occupancy by order or
         judgment of any court or by any legal process or writ, or under the
         terms of this Lease, (B) the benefits of any present or future
         constitution, statute, or rule of law that exempts property from
         liability for debt or for distress for Rent, (C) any provision of law
         relating to notice or delay in levy of execution in case of eviction of
         a Tenant for nonpayment of Rent, and (D) any rights, privileges, and
         liens set out under Section 91.004 and 93.003 of the Texas Property
         Code (as amended), and Tenant exempts Landlord from any liability or
         duty thereunder.

Section 9.04 Hazardous Substances

         (a) Tenant has no liability or responsibility with respect to Hazardous
         Substances, if any, which were placed or located within the Leased
         Premises or the Building prior to the Commencement Date, but Tenant may
         not, except as provided for herein:

                  (1) cause or permit the escape, disposal, or release in the
                  Leased Premises or the Building of any biologically active,
                  chemically active, or hazardous substances or materials
                  (hereafter referred to as "Hazardous Substances"); or

                  (2) bring or permit or allow any Tenant Party to bring, any
                  Hazardous Substances into the Leased Premises or the Building
                  except for Hazardous Substances which are used by Tenant in
                  conjunction with Tenant's business and which are maintained
                  and utilized by Tenant in accordance with Applicable Laws.

         The term Hazardous Substances includes, but is not limited to, those
         described in the Comprehensive Environmental Response Compensation and
         Liability Act of 1980, as amended, 42 U.S.C. Section 9601 et seq., the
         Resource Conservation and Recovery Act, as amended, 42 U.S.C. Section
         6901 et seq., the Texas Water Code, the Texas Solid Waste Disposal Act,
         and other applicable state or local environmental laws and the
         regulations adopted under those acts.

         Landlord consents to Tenant operating laboratories in the Leased
         Premises which will be used for research and development which may
         require the presence of the following: compressed air, vacuum, bottled
         carbon dioxide, liquid nitrogen, and Hazardous Substances which will be
         maintained and disposed of by Tenant in accordance with Applicable
         Laws.



                                       35
<PAGE>   36



         (b) If any lender or governmental agency requires testing to ascertain
         whether or not a release of Hazardous Substances has occurred in or on
         the Leased Premises or the Building based on probable cause that a
         release occurred and was caused by any Tenant or Tenant Party, then
         Tenant shall reimburse the reasonable costs of the testing to Landlord
         on demand as Rent if a release by Tenant or a Tenant Party actually
         occurred.

         (c) Each party shall execute affidavits, representations, and the like
         from time to time reasonably requested by the other party and in form
         and substance reasonably acceptable to the other party concerning such
         party's actual knowledge and belief regarding the presence of Hazardous
         Substances in the Leased Premises and the Building.

         (d) Tenant shall indemnify Landlord against any and all costs and
         expenses incurred by Landlord arising from any release of Hazardous
         Substances in or on the Leased Premises or the Building caused by any
         Tenant or Tenant Party.

         (e) Landlord shall be responsible for all Hazardous Substances, if any,
         which were placed or located within the Leased Premises and/or the
         Building prior to the Commencement Date. Landlord will indemnify and
         save and hold Tenant harmless from and against all claims, liabilities
         or obligations of any kind or nature arising in connection with: (i)
         any Hazardous Substances which were placed or located within the Leased
         Premises or the Building prior to the Commencement Date; and/or (ii)
         any release of Hazardous Substances in or on the Leased Premises or the
         Building caused by Landlord or by any person or entity operating by,
         through or under Landlord.

         (f) The provisions of this Section 9.04 survive the expiration or
         earlier termination of this Lease.

                      ARTICLE X - ASSIGNMENT AND SUBLETTING

Section 10.01 No Assignment or Subletting Without Consent.

         (a) Except as hereinafter provided, Tenant may not, without Landlord's
         prior written consent: (1) assign or transfer this Lease or any
         interest therein; (2) permit any assignment of this Lease or any
         interest therein by operation of law; (3) sublet the Leased Premises or
         any part thereof, (4) grant any license, concession, or other right of
         occupancy of any portion of the Leased Premises; (5) mortgage, pledge,
         or otherwise encumber its interest in this Lease; or (6) permit the use
         of the Leased Premises by any parties other than Tenant and its
         employees.

         (b) In the event Tenant desires the consent of Landlord to an
         assignment or subletting, Tenant shall submit to Landlord not less than
         fifteen (15) days prior to the effective date of the assignment or
         subletting a written notice of such fact which shall include copies of
         the final form of the documentation of the assignment or sublease and
         sufficient information to permit Landlord to determine the identity,
         character and financial condition of the proposed assignee or
         subtenant. Landlord shall either approve or reject Tenant's request
         within fifteen (15) days of receipt of Tenant's written notice.



                                       36
<PAGE>   37



Section 10.02 Landlord's Consent

         (a) Landlord's consent hereunder shall not be unreasonably withheld;
         provided, however, in granting or withholding its consent Landlord
         shall be entitled to take into consideration all relevant factors
         including without limitation, the creditworthiness, nature of the
         business and business reputation of the proposed subtenant or assignee
         and the parking requirements of the proposed subtenant or assignee to
         the extent and only to the extent such parking requirements exceed the
         parking requirements of Tenant. Landlord may, if it so elects, withhold
         its consent if the proposed subtenant or assignee is a government
         entity. Landlord may withhold or condition its consent subject to
         execution and delivery of an appropriate sublease or assignment which
         includes provisions for notice to Landlord, prohibition on further
         assignment or subleasing without Landlord's consent, except pursuant to
         the terms of this Lease and indemnification of Landlord by the
         subtenant or assignee. Landlord may withhold its consent to any
         proposed assignment or sublease if an Event of Default has occurred and
         is continuing, or an event has occurred which, with the giving of
         notice, or the passage of time, or both, could constitute any Event of
         Default. Landlord's consent to any assignment or subletting, is not a
         waiver of Landlord's right to approve or disapprove any subsequent
         assignment or subletting.

         (b) For any approved sublease or assignment, in the event the Base Rent
         paid by any assignee or subtenant exceeds the Base Rent due to Landlord
         from Tenant, Landlord shall be entitled to receive one-half ( 1/2) of
         such excess above the Base Rent after Tenant has received full
         reimbursement out of such excess of all reasonable sublease or
         assignment expenses, including but not limited to architectural fees,
         contractor fees, cost of leasehold improvements, rental abatement and
         legal and brokerage fees.

         (c) The provisions of Section 10.02(b) to the contrary notwithstanding,
         should Tenant request consent to enter into one or more subleases or
         assignments, which in the aggregate, cover more than (i) twenty-five
         percent (25%) of the Leased Premises and are for a period of time which
         extended into the final twenty-four (24) months of the Lease Term, or
         (ii) thirty-five percent (35%) or more of the Leased Premises, in
         either event, Landlord shall be entitled to recapture the portion of
         the Leased Premises under consideration for sublease or assignment by
         providing Tenant with written notice within ten (10) days of the date
         of the requested consent. In either event, Landlord and Tenant shall
         promptly enter into an amendment to this Lease reflecting such
         recapture of a portion of the Leased Premises as well as such other
         provisions which are required to reflect the conversion of the Building
         to a multi-tenant building, including but not limited to Building Rules
         and Regulations and parking regulations. Notwithstanding the above: (i)
         if Tenant exercises its renewal option with respect to any sublease
         space concurrently with the subleasing, then Landlord will have no
         right to recapture such space under the provisions of (i) the
         immediately preceding sentence; and (ii) Landlord's right of recapture
         will not apply to any subleases or assignments made pursuant to Section
         10.03 hereof and such subleases and assignments will not be included or
         considered under the provisions set forth hereinabove for the purpose
         of calculating the percentage of the Leased Premises which has been
         leased.

         (d) Notwithstanding the consent by Landlord to any assignment or
         subletting, Tenant shall remain liable for the payment of Rent and
         performance of all other obligations under this Lease.



                                       37
<PAGE>   38



         (e) Tenant shall have the right to erect partitions and demising walls
         to accommodate any sublease which is entered into by Tenant under the
         terms and provisions of this Lease.

Section 10.03 Permitted Transfers

         Notwithstanding anything to the contrary in this Lease, (a) an
         assignment or sublease to a subsidiary of Tenant or to an entity under
         joint ownership or control with Tenant, (b) the merger or transfer of
         all of the stock in Tenant; or (c) an assignment of the Lease in
         conjunction with the sale of all or substantially all of the assets of
         Tenant, shall be considered transfers permitted under this Lease
         provided in each such case the resulting entity's financial condition
         is equal to or better than Tenant's (a "Permitted Transfer").

                              ARTICLE XI - DEFAULT

Section 11.01 Default

         (a)      Each of the following shall constitute an "Event of Default"
                  by Tenant:

                  (1)      The Tenant abandons all or any part of the Leased
                           Premises and fails to pay one or more installments of
                           Base Rent or Additional Rent when the same is due; or

                  (2)      The filing of a petition by Tenant or by a third
                           party which is not contested by Tenant to declare
                           Tenant is bankrupt or to delay, reduce or modify
                           Tenant's debts or obligations, or for the appointment
                           of a receiver or trustee of Tenant or its property or
                           for the winding up or liquidation of its affairs; or
                           if Tenant makes an assignment of the benefits of
                           Tenant's creditors or admits in writing Tenant's
                           inability to pay the debts due; or

                  (3)      The failure of Tenant to pay when due any installment
                           of Base Rent, or Additional Rent, or any other money
                           payments due hereunder, or any part thereof, and such
                           failure shall continue for a period of five (5)
                           business days after Landlord has delivered to Tenant
                           written notice of such failure (provided, however,
                           that if Tenant fails to pay installments of Rent
                           hereunder on a timely basis on two (2) or more
                           occasions during any calendar year, then Landlord
                           will thereafter have no obligation to deliver any
                           notice of default to Tenant under the terms hereof
                           during the remainder of such calendar year and an
                           "Event of Default" will be deemed to have occurred
                           immediately upon the failure of Tenant to pay when
                           due any installment of Rent which comes due during
                           the remainder of such calendar year, without any
                           grace period and without necessity of Landlord
                           delivering any notice of default to Tenant); or

                  (4)      The failure of Tenant to fulfill or perform in whole
                           or in part, any agreement or provision of this Lease
                           which is an obligation upon Tenant, other than the
                           payment of Rent or any other money amounts due
                           hereunder, and such failure or nonperformance shall
                           continue for a period



                                       38
<PAGE>   39



                           of thirty (30) days after written notice thereof has
                           been given by Landlord to Tenant, or such longer
                           period as may be reasonably required to cure such
                           failure or nonperformance, provided that Tenant
                           commences curative action within such thirty (30) day
                           period and diligently pursues such curative action to
                           completion.

         (b)      Upon the occurrence of any Event of Default, Landlord shall
                  have the option to do any one or more of the following after
                  providing notices as set forth hereinbelow, but otherwise
                  without any notice or demand, in addition to and in limitation
                  of any other remedy permitted by law or by this lease:

                  (1)      Draw all or part of the Letter of Credit (after
                           compliance with Section 3.05 of the Lease and subject
                           to the limitations set out therein) and apply the
                           proceeds thereof to the payment of any amounts due to
                           Landlord hereunder and under the Tri-Party Agreement
                           (including the payment of any of Landlord's
                           Development Costs).

                  (2)      Apply all or part of the Cash Security Deposit to the
                           payment of amounts due to Landlord hereunder and
                           under the Tri-Party Agreement (including the payment
                           of any of Landlord's Development Costs after
                           compliance with Section 3.05 of the Lease and subject
                           to the limitations set out therein).

                  (3)      Terminate this Lease and forthwith repossess the
                           Leased Premises, and Landlord will be entitled to
                           recover forthwith as damages a sum of money equal to
                           the total of (i) the reasonable cost of recovering
                           the Leased Premises (including attorneys' fees and
                           costs of suit); (ii) the unpaid Rent earned at the
                           time of termination, plus interest thereon at the
                           Interest Rate; (iii) an amount equal to the total
                           Base Rent payable during the remainder of the Lease
                           Term discounted to present value at a per annum rate
                           equal to the "Discount Rate" as published on the date
                           this Lease is terminated by the Wall Street Journal,
                           Southwest Edition, in its listing of "Money Rates",
                           less the present value (discounted at the same rate)
                           of the fair market rental value of the Leased
                           Premises for said period; and (iv) Landlord's
                           Development Costs and any other sum of money and
                           damages owed by Tenant to Landlord; provided,
                           however, that in determining the actual damages due
                           to Landlord, proper credit shall be given for any
                           portion of the Security previously applied by
                           Landlord to the payment of such damages or available
                           to Landlord for such payment, as provided in Section
                           3.05(d) hereof.

                  (4)      Terminate Tenant's right to possession of the Leased
                           Premises without terminating this Lease by giving
                           written notice thereof to Tenant, in which event
                           Tenant shall pay to Landlord (i) all Rent and other
                           amounts accrued hereunder (including the Landlord's
                           Development Costs) to the date of termination of
                           possession, (ii) the reasonable cost of recovering
                           the Leased Premises (including reasonable attorneys'
                           fees and costs of suit), and (iii) all Rent and other
                           sums required hereunder to be paid by Tenant during
                           the



                                       39
<PAGE>   40



                           remainder of the Lease Term, diminished by any net
                           sums thereafter received by Landlord through
                           reletting the Leased Premises during such period;
                           provided, however, that in determining the actual
                           damages due to Landlord, proper credit shall be given
                           for any portion of the Security previously applied by
                           Landlord to the payment of such damages or available
                           to Landlord for such payment, as provided in Section
                           3.05(d) hereof. Landlord shall use reasonable efforts
                           to relet the Leased Premises on such terms and
                           conditions as Landlord in its reasonable discretion
                           may determine (including the terms and conditions
                           specified in Section 11.03). Subject to the
                           provisions of Section 11.03, Landlord shall not be
                           liable for, nor shall Tenant's obligations hereunder
                           be diminished because of, Landlord's failure to relet
                           the Leased Premises or to collect rent due for such
                           reletting. Tenant shall not be entitled to the excess
                           of any consideration obtained by reletting over the
                           Rent due hereunder. Reentry by Landlord in the Leased
                           Premises shall not affect Tenant's obligations
                           hereunder for the unexpired Lease Term; rather,
                           Landlord may, from time to time, bring action against
                           Tenant to collect amounts due by Tenant, without the
                           necessity of Landlord's waiting until the expiration
                           of the Lease Term. Unless Landlord delivers written
                           notice to Tenant expressly stating that it has
                           elected to terminate this Lease, all actions taken by
                           Landlord to exclude or dispossess Tenant of the
                           Leased Premises shall be deemed to be taken under
                           this Section 11.01(b)(4). If Landlord elects to
                           proceed under this Section 11.01(b)(4), it may at any
                           time elect to terminate this Lease under Section
                           11.01(b)(3).

                  (5)      Landlord may make such payments and/or take such
                           actions (including, without limitation, entering upon
                           or within the Leased Premises) and do whatever Tenant
                           is obligated to do under the terms of this Lease, and
                           Tenant covenants and agrees to reimburse Landlord on
                           demand for any expenses which Landlord may incur in
                           effecting compliance with Tenant's obligations under
                           this Lease, together with interest thereon at the
                           Interest Rate from the date paid by Landlord.

                  (6)      After terminating this Lease or Tenant's right to
                           possession of the Leased Premises, Landlord may
                           deliver to Tenant written notice that Landlord
                           intends to remove Tenant's personal property from the
                           Leased Premises, and if Tenant fails to remove
                           Tenant's personal property from the Leased Premises
                           within ten (10) days after Tenant's receipt of such
                           notice, then Landlord may remove any and all personal
                           property located in the Leased Premises and either
                           dispose of or store such personal property at
                           Tenant's expense.

                  (7)      In addition to the other remedies provided in this
                           Lease, Landlord shall be entitled, to the extent
                           permitted by applicable law, to injunctive relief in
                           case of the violation or attempted or threatened
                           violation, of any of the provisions of this Lease, or
                           to a decree compelling performance of any other
                           provisions of this Lease, or to any other remedy
                           allowed at law or in equity.



                                       40
<PAGE>   41



         Tenant and Landlord intend that this Lease evidence the obligations of
         Landlord, as developer, regarding the development of the Land and the
         construction of the Building, as well as, the obligations of Landlord
         and Tenant, as lessor and lessee. Tenant and Landlord acknowledge and
         agree that, due to the peculiar nature of this transaction and the
         particular development obligations to be assumed by Landlord to perform
         its duties hereunder, the recovery by Landlord of damages adequate to
         cover up to $9,000,000 of Landlord's Development Costs shall not be
         limited by the foregoing provisions regarding the calculation and
         acceleration of Rent. Instead, Landlord's right to recover damages
         adequate to cover Landlord's Development Costs addressed in Section
         3.05 hereinabove and Landlord's rights in that regard are limited by
         and subject to the terms and provisions which are set out in Section
         3.05 hereinabove. In addition, Landlord is subject to the reimbursement
         obligations set out in Section 3.05 hereinabove if Landlord collects or
         receives any Excess Funds.

         Notwithstanding any other remedy or provision set forth in this Lease:
         (i) this Lease may be terminated by Landlord only by written notice of
         such termination from Landlord to Tenant given in accordance with the
         notice provisions of this Lease; (ii) this Lease may be terminated by
         Tenant only by written notice of such termination from Tenant to
         Landlord given in accordance with the notice provisions of this Lease
         and no other act or omission of Tenant shall be construed as a
         termination of this Lease; (iii) all rights and remedies of Landlord
         and Tenant herein or existing at law or in equity are cumulative and
         the exercise of one or more rights or remedies shall not be taken to
         exclude or waive the right to the exercise of any other; (iv) Tenant
         agrees that acceptance of full or partial payments by Landlord after
         notice of termination or forfeiture will not constitute a waiver of the
         default, termination, or forfeiture unless Landlord agrees to a waiver
         in writing, nor affect any legal proceedings taken or to be taken by
         Landlord except to reduce Tenant's obligation to Landlord by the amount
         of such payment; (v) waiver by either party of any defaults or breaches
         by the other party of any provisions of this Lease shall not bar the
         non-defaulting party thereafter from requiring prompt performance by
         the defaulting party of the obligations of this Lease, nor shall the
         non-defaulting party be barred thereafter from immediate exercise of
         any of the non-defaulting party's rights or remedies in case of
         continuing or subsequent default or violation by the defaulting party;
         and (vi) Landlord acknowledges that should it be determined that
         Landlord's actual damages resulting from the Event(s) of Default by
         Tenant are less than the portion of the Security applied by Landlord to
         the payment of its damages hereunder, Landlord will return such excess
         to Tenant within ten (10) business days after Landlord's actual damages
         are determined.

Section 11.02 Landlord's Lien

     All statutory and contractual liens for rent are hereby waived by Landlord.

Section 11.03 Mitigation of Damages

     (a) Both Landlord and Tenant shall each use commercially reasonably efforts
         to mitigate any damages resulting from a default of the other party
         under this Lease.

     (b) Landlord and Tenant agree to the following criteria in connection with
         Landlord's obligation to mitigate damages after a default by Tenant
         under this Lease:



                                       41
<PAGE>   42



                  (1)      Landlord will have no obligation to solicit or
                           entertain negotiations with any other prospective
                           tenants of the Leased Premises until and unless
                           Landlord obtains full and complete possession of the
                           Leased Premises, including without limitation, the
                           final and unappealable legal right to relet the
                           Leased Premises free of any claim of Tenant.

                  (2)      Landlord will not be obligated to offer the Leased
                           Premises to a prospective tenant when other premises
                           suitable for that prospective tenant's use are (or
                           soon will be) in buildings owned by affiliates of
                           Landlord in the Terrace P.U.D. For all purposes under
                           this Lease, affiliates of Landlord shall mean and
                           include (i) any person or entity owning or holding
                           (directly or indirectly) any interest in Landlord;
                           and (ii) any entity in which Landlord or any person
                           or entity owning or holding any interest (directly or
                           indirectly) in Landlord, owns or holds any interest
                           (directly or indirectly).

                  (3)      Landlord will not have any obligation to lease the
                           Leased Premises for any rental less than the current
                           rate then prevailing for similar space in comparable
                           buildings in the same market area as the Building nor
                           shall Landlord be obligated to enter into a new lease
                           under any terms or conditions that are unacceptable
                           to Landlord under Landlord's then current leasing
                           policies for space which is comparable to the
                           Building.

                  (4)      Landlord will not be obligated to enter into any
                           lease with any prospective tenant whose presence or
                           operations in the Building would: (i) violate any
                           restriction, covenant or requirement contained in the
                           lease of another tenant in the Building; (ii)
                           materially adversely affect the reputation of the
                           Building; or (iii) be materially incompatible with
                           the operation of the Building as a first class office
                           building.

                  (5)      Landlord will not be obligated to enter into a lease
                           with any prospective tenant which does not have, in
                           Landlord's reasonable judgment and opinion,
                           sufficient financial resources and operating
                           experience to operate the Leased Premises in a first
                           class manner and meet its financial obligations.


                  (6)      Landlord will not be required to expand any amount of
                           money to alter, remodel or otherwise make the Leased
                           Premises suitable for use by any prospective tenant.

                  (7)      Landlord will have no obligation to advertise or
                           expend any sums of money to market the Leased
                           Premises.

         If Landlord makes the Leased Premises available for reletting under the
         criteria set forth hereinabove, Landlord will be deemed to have fully
         satisfied Landlord's obligation to mitigate damages under this Lease
         and under any law or judicial ruling in effect on the date of this
         Lease or at the time of Tenant's default, and Tenant hereby waives and



                                       42
<PAGE>   43



         releases, to the fullest extent legally permissible, any right to
         assert in any action by Landlord to enforce the terms of this Lease,
         any defense, counterclaim, or rights of set-off or recoupment
         respecting the mitigation of damages by Landlord (or alleged failure by
         Landlord to adequately mitigate its damages), unless and to the extent
         Landlord maliciously or in bad faith fails to act in accordance with
         the requirements of this Section 11.03.

     (c) Tenant's right to seek mitigation as a result of a default by Landlord
         under this Section 11.03 shall be conditioned on Tenant taking such
         action as is reasonably required, under the circumstances, to minimize
         any loss or damage to Tenant's property or business, or to any of
         Tenant's officers, employees, agents, invitees, or other third parties
         that may be caused by any such default of Landlord.

                      ARTICLE XII- MISCELLANEOUS PROVISIONS

Section 12.01 Rights Reserved by Landlord

         Landlord reserves the following rights, which may be exercised by
         Landlord at any time and from time to time without notice and without
         liability to Tenant or Tenant Party for damage or injury to property,
         persons, or business. Tenant agrees that the exercise by Landlord of
         any of the following rights will not create or give rise to any
         eviction, constructive or actual, or disturbance of Tenant's use or
         possession or giving rise to any claim for set-off or abatement of
         Rent, provided the exercise of such rights do not unreasonably
         interfere with Tenant's occupancy of the Leased Premises or breach the
         provisions of this Lease. The rights reserved by Landlord hereunder are
         as follows:

         (a)  Subject to Section 13.02, to install, affix, and maintain
              directional or informational signage on the exterior and interior
              of the Building similar to other buildings in the Terrace P.U.D.
              (but as long as Tenant is the sole tenant of the Building,
              Landlord will not have the right to place any other tenant
              identification signs on the Building).

         (b)  To approve, prior to installation, all types of window shades,
              blinds, drapes, awnings, window ventilators, and similar equipment
              and to control all internal lighting that is visible from the
              exterior of the Building; provided, however, that Landlord's
              approval will not be unreasonably withheld and Landlord's control
              will not be unreasonably exercised.

         (c)  Subject to the terms and provisions of Section 13.09 of this
              Lease, to enter upon the Leased Premises at reasonable business
              hours to inspect, clean, or make repairs or alterations to the
              Leased Premises (but without any obligation to do so, except as
              expressly specified in this Lease), to make repairs or alterations
              to any part of the Building or the Building systems (including
              adjacent premises), to show the Leased Premises to prospective
              lenders, purchasers, and, during the last nine (9) months of the
              Lease Term, to show the Leased Premises to prospective tenants
              during reasonable business hours and, if the Leased Premises are
              vacant, to prepare them for re-occupancy.



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<PAGE>   44



         (d)  To retain at all times, and to use in appropriate instances,
              master keys to all doors within and into the Leased Premises.
              Tenant may change and re-key locks from time to time, and at any
              time, so long as Landlord is provided with master keys. Landlord
              will strictly control access to all master keys and Landlord will
              provide to Tenant in writing a list of all persons who are
              provided with access to the master keys other than the names of
              cleaning staff.

         (e)  To decorate and make reasonable repairs, alterations, additions,
              changes, or improvements, whether structural or otherwise, in and
              about the Building and for those purposes to enter upon the Leased
              Premises (after giving Tenant reasonable notice thereof, which may
              be oral notice, except in cases of real or apparent emergency, in
              which case no notice will be required) and, during the continuance
              of the work, temporarily close doors, entryways, public space, and
              corridors in the Building, to interrupt or temporarily suspend
              Building services and facilities, and to change the arrangement
              and location of entrances or passageways, doors and doorways,
              corridors, elevators, stairs, toilets, or other public parts of
              the Building, all without abatement or set off of Rent or
              affecting any of Tenant's obligations under this Lease, so long as
              the Leased Premises are reasonable accessible. Landlord will use
              reasonable efforts not to disrupt Tenant's normal business
              routine.

         (f)  To have and retain a paramount title to the Leased Premises and
              the Building free and clear of any act of Tenant purporting to
              burden or encumber the Leased Premises or the Building, except as
              permitted under this Lease.

         (g)  To approve the weight, size, and location of safes, heavy
              equipment, file cabinets, book shelves, and other heavy items in
              and about the Leased Premises and the Building.

         (h)  To require all those items and all furniture to be moved into and
              out of the Building and the Leased Premises only at times and in a
              manner reasonably specified by Landlord after advance notice has
              been given by Tenant to Landlord. Movements of Tenant's property
              into or out of the Building and within the Building are entirely
              at the risk and responsibility of Tenant.

         (i)  To have access for Landlord and other tenants in the building to
              any mail chutes or other depositories located on the Leased
              Premises according to the rules of the United States Postal
              Service.

         (j)  To take reasonable measures as Landlord deems advisable for the
              security of the Building and its occupants (including, in
              emergency situations only, the search of all persons entering or
              leaving the Building), the evacuation of the Building for cause,
              suspected cause, or for drill purposes, and the temporary denial
              of access to the Building in emergency situations only.

         (k)  After the completion of the construction of the Building, to
              transfer, assign or convey, in whole or in part, the Building and
              Landlord's rights under this Lease to any party who acquires title
              to the Building. If Landlord transfers, assigns, or conveys its
              rights under this Lease, Landlord is released from any further
              obligations under this Lease



                                       44
<PAGE>   45

              provided such transferee assumes such obligations in a written
              agreement which is delivered to Tenant and which provides for the
              assumption by the transferee of all of the obligations to Tenant
              under this Lease, and thereafter, and Tenant shall look solely to
              the successor in interest of Landlord for performance of the
              obligations of "Landlord" under this Lease. Landlord agrees to
              keep the terms and conditions of any sale of the Building
              confidential and to require any purchaser of the Building to also
              keep such terms and conditions confidential; provided, however,
              that Landlord and such purchaser may disclose such terms and
              conditions to their employees and consultants who have a need to
              know and to their respective lenders and financial partners.

Section 12.02 Taxes on Tenant's Property

         Tenant shall pay, and indemnify, defend, and hold Landlord harmless
         against, all taxes levied or assessed against personal property,
         furniture, fixtures, or other improvements placed by or for Tenant in
         the Leased Premises. If any taxes for which Tenant is liable are levied
         or assessed against Landlord or Landlord's property and if Landlord is
         required to pay the taxes or if the assessed value of Landlord's
         property is increased by inclusion of personal property, furniture,
         fixtures, or other improvements placed by or for Tenant in the Leased
         Premises and Landlord elects to pay the increased taxes, Tenant shall
         pay to Landlord on demand as additional Rent that part of the taxes for
         which Tenant is liable under this Section.

Section 12.03 Attorneys' Fees and Legal Expenses

         If either party files litigation concerning the interpretation or
         enforcement of this Lease, the prevailing party is entitled to recover
         from the losing party the prevailing party's reasonable attorneys'
         fees, court costs, and expenses, both at the trial level and at the
         appellate level.

 Section 12.04 Subordination

         (a) This Lease and all rights of Tenant under this Lease are subject
         and subordinate to:

                  (1) any mortgage or deed of trust secured by a lien against
                      the Building and/or the Land (a "Mortgage"), or any ground
                      lease or master lease (a "Primary Lease") that now or
                      hereafter covers all or any part of the Leased Premises
                      (the mortgagee under any Mortgage or the lessor under any
                      Primary Lease is referred to herein as "Landlord's
                      Mortgagee"); and

                  (2) all increases, renewals, modifications, consolidations,
                      replacements, and extensions of any Mortgage or Primary
                      Lease;

         Landlord warrants and represents on the Effective Date that the Leased
         Premises is free and clear of liens and encumbrances, except for liens
         and encumbrances held by Bank One, Texas, N.A. Within ten (10) days of
         the execution hereof, Tenant and Landlord's Mortgagee shall enter into
         a subordination, non-disturbance and attornment agreement,
         substantially in the form of Exhibit G attached hereto ("SNDA"). The
         subordination of this Lease to any future mortgagee shall be
         conditioned upon the future mortgagee



                                       45
<PAGE>   46



         entering into (and delivering to Tenant) a SNDA substantially in the
         same form as that executed contemporaneously with the execution hereof
         or another form reasonably acceptable to Tenant and the future
         mortgagee. Tenant shall, upon demand at any time or times, execute,
         acknowledge, and deliver to Landlord, or to Landlord's Mortgagee, any
         instruments that may be reasonably requested by Landlord or any
         Landlord's Mortgagee to more effectively effect or evidence this
         subordination to any Mortgage or Primary Lease.

         (b) If any Mortgage against the Building is foreclosed, and if the
         mortgagee thereunder has executed and delivered to Tenant an SNDA in
         substantially the same form as that attached hereto as Exhibit G,
         Tenant shall, upon request by the purchaser at the foreclosure sale:

                  (1) attorn to the purchaser and recognize the purchaser as
                      "Landlord" under this Lease; and

                  (2) execute, acknowledge, and delivery to the purchaser an
                      agreement confirming such attornment as such purchaser may
                      reasonably request.

         (c) Tenant waives the provisions of any statute or rule of law, now or
         hereafter in effect, that may give or purport to give Tenant any right
         or election to terminate or otherwise adversely affect this Lease and
         the obligations of Tenant under this Lease if any foreclosure sale
         occurs. This Lease is not affected in any way whatsoever by any
         foreclosure sale unless the holder(s) of the indebtedness or other
         obligations secured by the Mortgage declare otherwise pursuant to the
         terms of the SNDA with such holder(s).

Section 12.05 Estoppel Certificates

         Tenant shall, from time to time within twenty (20) days after receipt
         of a request for same, execute, acknowledge, and deliver to Landlord an
         estoppel certificate in substantially the form attached as Exhibit F,
         with such changes as may be necessary to conform such estoppel
         certificate to the facts which exist at the time. Landlord shall, from
         time to time, within twenty (20) days after receipt of a request for
         same, execute, acknowledge and deliver to Tenant estoppel certificates
         in such form as may be reasonably requested by Tenant. Tenant
         specifically agrees to execute an estoppel to Landlord's Mortgagee at
         the time Landlord's Mortgagee is obligated to close the construction
         loan for the construction of the Building.

Section 12.06 Financial Statements

         Tenant will, from time to time, within twenty (20) days after receipt
         of a written request for same, but not more than twice in any one
         twelve (12) month period, furnish to Landlord copies of the most recent
         public annual or quarterly SEC report of Tenant.

Section 12.07 Notices

         All notices, requests, approvals, and other communications required or
         permitted to be delivered under this Lease must be in writing and are
         effective:



                                       46
<PAGE>   47



         (a) on the same business day sent, if sent by telecopier prior to 5:00
         P.M., Austin, Texas time and the sending telecopier generates a written
         confirmation of sending (provided, however, that an additional copy of
         the notice, request, approval, or other communication must be delivered
         by United States mail, certified, return receipt requested, and postage
         prepaid;

         (b) the next business day after delivery on a business day to a
         nationally recognized overnight courier service for prepaid overnight
         delivery;

         (c) if orderly delivery of the mail is not then disrupted or
         threatened, in which event some method of delivery other than the mail
         must be used, 3 business days after being deposited in the United
         States mail, certified, return receipt requested, postage prepaid; or

         (d) upon receipt if delivered personally or by any method other than by
         telecopier (with written confirmation),
         nationally-recognized-overnight-courier service, or mail;

         in each instance addressed to Landlord or Tenant, as the case may be,
         at the address or the addresses (if more than one) specified for such
         party in the Basic Lease Provisions, or to any other address or
         addresses either party may designate by ten (10) days' prior notice to
         the other party.


Section 12.08 Business Purpose

         Tenant represents that this Lease is executed by Tenant, and all
         obligations of Tenant arising out of this Lease are, primarily for
         business or commercial purposes and not for personal, family, or
         household purposes.

Section 12.09 Severability

         Each of the terms of this Lease is, and must be construed to be,
         separate and independent. If any of the terms of this Lease or its
         application to any person or circumstances is to any extent invalid and
         unenforceable, the remainder of this Lease, or the application of that
         term to persons or circumstances other than those as to which it is
         invalid or unenforceable, are not affected thereby.

Section 12.10 No Merger

         The fact that the same person may acquire or hold, directly or
         indirectly, this Lease or the leasehold estate hereby created or any
         interest in this Lease or in the leasehold estate as well as the fee
         estate in the Leased Premises or any interest in the fee estate does
         not cause a merger of this Lease or of the leasehold estate hereby
         created with the fee estate in the Leased Premises.

Section 12.11 Force Majeure

         When this Lease prescribes a period of time for action to be taken by
         Landlord or Tenant (except for the payment of money), neither Landlord
         nor Tenant will be liable or



                                       47
<PAGE>   48



         responsible for, and there is excluded from the computation for the
         period of time, any delays due to strikes, acts of God, shortages of
         labor or materials, war, governmental laws, regulations, restrictions,
         or any other cause of any kind that is beyond the control of such
         party.

Section 12.12 Gender

         Words of any gender used in this Lease include any other gender and
         words in the singular number include the plural, unless the context
         otherwise requires.

Section 12.13 Joint and Several Liability

         If there is more than one Tenant, the obligations imposed upon Tenant
         under this Lease are joint and several.

Section 12.14 No Representations

         Landlord and Landlord's agents made no representations or promises with
         respect to the Leased Premises or the Building except as expressly set
         forth in this Lease. No rights, easements, or licenses are acquired by
         Tenant by implication or otherwise except as expressly set forth in
         this Lease.

Section 12.15 Entire Agreement; Amendments

         This Lease is the entire agreement between the parties and supersedes
         all negotiations, considerations, representations, and understandings
         between Landlord and Tenant prior to the date hereof. No act or
         omission of any employee or agent of Landlord or of Landlord's Broker
         may alter, change, or modify any of the terms of this Lease. Similarly,
         no act or omission of any employee or agent of Tenant or of Tenant's
         broker may alter, change or modify any of the terms of this Lease. No
         amendment or modification of this Lease is binding unless expressed in
         a written instrument executed for that purpose by Landlord and Tenant.

Section 12.16 Section Headings

         The section headings in this Lease are for convenience only and in no
         way enlarge or limit the scope or meaning of the paragraphs in this
         Lease.

Section 12.17 Binding Effect

         All terms of this Lease are binding upon the respective heirs, personal
         representatives, successors, and, to the extent assignment is
         permitted, assigns of Landlord and Tenant.

Section 12.18 Counterparts

         This Lease may be executed in two or more counterparts, each of which
         is deemed an original and all of which together constitute one and the
         same instrument.



                                       48
<PAGE>   49



Section 12.19 Rental Tax

         Tenant shall pay as Rent all licenses, charges, and other fees of every
         kind and nature as and when they become due arising out of or in
         connection with Tenant's use and occupancy of the Leased Premises and
         the Building (including the Garage), including but not limited to
         license fees, business license taxes, and privilege, sales, excise, or
         other taxes (other than income taxes, franchise taxes and other similar
         taxes) imposed upon Rent or upon services provided by Landlord or upon
         Landlord in an amount measured by Rent received by Landlord.

Section 12.20 Authority to Sign Lease

         If either Landlord or Tenant is a corporation or a partnership (general
         or limited), Landlord and Tenant, as applicable, represent each to the
         other that the person(s) signing this Lease as an officer or partner of
         each party hereto represents to the other that such person(s) is
         authorized to execute this Lease without the necessity of obtaining any
         other signature of any other officer or partner, that the execution of
         this Lease has been authorized by the board of directors of the
         corporation or by the partners of the partnership, as the case may be,
         and that this Lease is fully binding on Landlord or Tenant, as
         applicable. Landlord or Tenant each reserve the right to request
         evidence of the approval of this Lease and authorization of other
         party's signatories to bind such party, which evidence shall be
         satisfactory in form and content to Landlord and Tenant, as applicable,
         and their respective counsel.

Section 12.21 Execution and Approval of Lease

         Employees and agents of Landlord, Landlord's broker, Tenant and
         Tenant's broker have no authority to make or agree to make a lease or
         any other agreement or undertaking in connection herewith. The
         submission of this Lease for examination and negotiation is not an
         offer to lease, agreement to reserve, or option to lease the Leased
         Premises. This Lease is effective and binding on Landlord only upon the
         execution and delivery of this Lease by Landlord and Tenant.

Section 12.22 Time of the Essence

         Time is of the essence in connection with each provision of this Lease.

Section 12.23 No Personal Liability of Landlord or Guarantor

         Except as provided hereinbelow, with respect to the "Guaranteed
         Obligations" (i) if Landlord shall fail to perform any covenant, term
         or condition of this Lease and if, as a consequence of such failure,
         Tenant shall recover a money judgment against Landlord, such judgment
         shall be satisfied only out of the proceeds received at a judicial sale
         upon execution and levy against the right, title and interest of
         Landlord in the Building and in the rents, income or other proceeds
         from the Building receivable by Landlord; and (ii) neither Landlord nor
         Landlord's affiliate companies nor their respective owners, partners,
         venturers, shareholders, directors or officers shall have any personal,
         corporate or other liability hereunder.



                                       49
<PAGE>   50



         Tenant covenants and agrees not to bring suit against: (i) the owners,
         partners, venturers, shareholders, directors or officers of Landlord
         and/or any affiliate of Landlord; or (ii) any affiliate of Landlord.
         Notwithstanding any provisions herein to the contrary, Landlord shall
         have personal liability with respect to the Guaranteed Obligations. W&G
         Partnership, Ltd. shall guarantee the performance of the Guaranteed
         Obligations and shall have personal liability therefor (but none of the
         owners, partners, venturers, shareholders, directors or officers of
         Landlord shall have any personal liability therefor) for so long as
         Desta Five Partnership, Ltd. or any other affiliate of W&G Partnership,
         Ltd. is the owner of the Building. Notwithstanding the provisions of
         the first sentence of this paragraph, Tenant will have the right to
         bring suit against W&G Partnership, Ltd. with respect to the Guaranteed
         Obligations. For purposes hereof the "Guaranteed Obligations" mean and
         refer to all liabilities and/or obligations which may arise out of or
         as a result of: (i) Landlord's failure to apply insurance proceeds or
         condemnation awards in accordance with the terms of this Lease; (ii)
         the misappropriation of escrowed Operating Expenses; or (iii) damages
         caused by a breach of Landlord's covenant of quiet enjoyment.

                      ARTICLE XIII - ADDITIONAL AGREEMENTS

Section 13.01 Parking


(a)  During the initial Lease Term and at no cost to Tenant, Landlord shall
     provide to Tenant all of the parking spaces (which shall be a minimum of
     768 spaces) in the Garage and all of the surface parking spaces on the
     Land. Landlord and Tenant will work together during the design and
     operation of the Garage regarding parking space sizes, percentages, and
     number of reserved spaces. Thereafter, Tenant will have the right from time
     to time to restripe the Garage with such parking configurations as may be
     desired by Tenant from time to time. Additionally, Tenant may, from time to
     time, designate certain parking spaces in the Garage as reserved spaces.

(b)  All Tenant Parties must comply with all traffic, security, safety, and
     other rules and regulations reasonably promulgated from time to time with
     respect to the Garage.

(c)  Landlord shall provide in the Garage bicycle racks which are adequate for
     Tenant's employees.

(d)  Landlord shall not be responsible for money, jewelry, automobiles or other
     personal property lost in or stolen from the Garage regardless of whether
     such loss or theft occurs when the Garage or other areas therein are locked
     or otherwise secured against entry. Except as caused by the gross
     negligence or willful misconduct of Landlord, Landlord shall not be liable
     for any loss, injury or damage to persons using the Garage or automobiles
     or other property therein, it being agreed that, to the fullest extent
     permitted by law, the use of the Garage and the spaces shall be at the sole
     risk of Tenant and its employees.

(e)  Landlord shall have the right from time to time to promulgate reasonable
     rules and regulations regarding the Garage, the spaces and the use thereof,
     including, but not limited to, rules and regulations controlling the flow
     of traffic to and from various parking areas, the angle and direction of
     parking, and the like. Tenant shall comply with and cause its employees to



                                       50
<PAGE>   51



     comply with all such rules and regulations as well as all reasonable
     additions and amendments thereto.

(f)  Except for emergency repairs, Tenant and its employees shall not perform
     any work on any automobiles while located in the Garage or the Leased
     Premises.

(g)  Landlord shall have the right to temporarily close the Garage or certain
     areas therein in order to perform necessary repairs, maintenance and
     improvements to the Garage; provided, however, that all such closures will
     be limited in duration and scope to the extent possible and, except in
     emergency situations, such closings will not occur during normal business
     hours.

(h)  Tenant shall not assign or sublease any of the spaces without the consent
     of Landlord except, however, that Tenant may assign or sublease parking
     spaces without Landlord's consent in conjunction with any assignment or
     sublease which is permitted or consented to under Article X of this Lease.

(i)  At Tenant's option and election, Landlord, at Tenant's sole cost and
     expense, will install in the Garage a card-key access security system
     designed to specifications approved by Tenant and designed to be compatible
     with Tenant's security system in the Leased Premises.

Section 13.02 Signage

     (a) Landlord agrees that Tenant has the exclusive right to install
         illuminated signage with Tenant's name and logo (if any) near the top
         of the Building (and on the sides of the Building facing Loop 1 and/or
         Via Fortuna) and at the entrance to the Building as well as on the
         monument sign on the Land. In addition, Tenant has the non-exclusive
         right to have its name included on the monument sign at one of the
         entrances to the Terrace P.U.D. when such sign is constructed. All
         signs shall conform to the design and aesthetics of other signage
         within the Terrace P.U.D. and must be approved by the Architectural
         Committee of the Terrace P.U.D. Association, which approval shall not
         be unreasonably withheld. The monument signs will be placed at
         locations to be determined by Tenant and Landlord, and subject to the
         Terrace P.U.D. and City of Austin signage guidelines and ordinances.
         Landlord shall be responsible for all sign maintenance.

     (b) Landlord agrees that the initial costs for the signage located on the
         exterior of the Building, if any, may be paid for out of the Allowance
         described in the Tenant Work Letter. Maintenance of the signs will be
         an Operating Expense.

Section 13.03 Tenant's Ability to Perform Landlord's Unperformed Obligations

         Notwithstanding anything to the contrary contained in this Lease, if
         Landlord shall fail to perform any of the terms, provisions, covenants
         or conditions to be performed or complied with by Landlord under
         Section 6.04 of this Lease with respect only to the Leased Premises
         (such terms, provisions, covenants or conditions are referred to
         herein, collectively as "Landlord Repair Obligations") or Section 7.02
         of this Lease (the "Landlord Insurance Obligations") after expiration
         of a twenty (20) day notice and cure period for Landlord and Landlord's
         Mortgagee, then Tenant may, at Tenant's option and risk, but without
         any obligation to do so, after delivery of an additional twenty (20)
         day



                                       51
<PAGE>   52



         prior written notice to Landlord and Landlord's Mortgagee, perform such
         Landlord Repair Obligations or Landlord Insurance Obligations on
         Landlord's behalf. If Tenant so performs any of such Landlord Repair
         Obligations hereunder, then Tenant will perform such Landlord Repair
         Obligations (1) in compliance with all Applicable Laws, regulations and
         requirements to which Landlord would be subject under this Lease (if
         Landlord were performing such Landlord Repair Obligations), (2) using
         materials of a quality and grade at least equal to that in place as of
         the date of delivery of the Leased Premises to Tenant, if applicable,
         (3) without interfering with the rights of other tenants of the
         Building, and (4) in compliance with all applicable warranties or
         guarantees in effect with respect to the Building. Tenant will promptly
         assign to Landlord any warranties or guaranties in respect of any
         Landlord Repair Obligations. If Tenant so performs any of the Landlord
         Repair Obligations or Landlord Insurance Obligations hereunder, the
         full amount of the fair and reasonable costs and expenses incurred by
         Tenant shall be owing by Landlord to Tenant, and Landlord shall pay to
         Tenant the full undisputed amount thereof plus interest at the Interest
         Rate from the date of payment of such obligations by Tenant until paid
         by Landlord, within ten (10) business days of Landlord's receipt of
         Tenant's written demand therefor (together with reasonable evidence
         verifying the amount of such costs and expenses).

Section 13.04 Real Estate Brokers

         Landlord represents to Tenant that it has not dealt with any real
         estate broker with respect to this Lease except for Colliers Oxford
         Commercial, Inc. ("COCI"). Tenant represents to Landlord that it has
         not dealt with any real estate broker with respect to this Lease except
         for NAI/Commercial Industrial Properties Company ("CIP") and CIP's
         affiliate, NAI/BT Commercial in Palo Alto, California ("NAI/BT").
         Landlord agrees to pay to COCI and CIP brokerage commissions in
         connection with this Lease pursuant to separate written agreements with
         COCI and CIP. CIP will be responsible for any sums payable to NAI/BT.
         Landlord and Tenant will indemnify and defend the other against any
         claims by any other broker or third party claiming through Landlord or
         Tenant, as applicable, for any real estate payment of any kind in
         connection with this Lease.

Section 13.05 Conditions Precedent

         Notwithstanding any provision in this Lease to the contrary, Tenant's
         obligations under this Lease are expressly subject to and conditioned
         upon the satisfaction of the following conditions precedent:

                  (a) Landlord's delivery to Tenant of Landlord's proposed
                  subdivision plat (which must provide for the subdivision of
                  the Land into a separate legal lot) and Landlord's proposed
                  application for a site development permit (which is to be
                  reviewed and approved by Tenant prior to filing with the City
                  of Austin and will not be materially changed without further
                  review and approval by Tenant) within sixty (60) days of the
                  Effective Date, (such subdivision plat and site development
                  permit referred to herein collectively as the "Governmental
                  Permits");

                  (b) the delivery by Landlord to Tenant of written confirmation
                  in a form reasonably acceptable to Tenant that all of the
                  Governmental Permits have been



                                       52
<PAGE>   53



                  finally approved by all applicable governmental authorities
                  and are in final form and condition, not subject to any
                  further appeals or conditions on or before June 1, 2001;

                  (c) the delivery by Landlord to Tenant of written confirmation
                  from the City of Austin in form reasonably acceptable to
                  Tenant verifying that the Building may be utilized for the
                  Permitted Use and specifically confirming that Tenant may
                  utilize up to ten percent (10%) of the Leased Premises for
                  research services as an accessory use in conjunction with the
                  research and development activities of Tenant within the
                  Leased Premises.

Section 13.06 Title, Survey and Environmental Report

         (a) Title Commitment. Within ten (10) days after the Effective Date of
         this Lease, Landlord shall furnish to Tenant a title commitment
         ("Commitment") issued by Heritage Title Company showing Landlord as the
         record fee title owner of the Land, by the terms of which the Title
         Company agrees to issue to Tenant a leasehold policy of title insurance
         ("Title Policy") on the standard form promulgated by the Department of
         Insurance of the State of Texas, insuring Tenant's leasehold estate to
         be good and indefeasible subject to the terms of such policy and the
         Schedule B exceptions, together with legible copies of all documents
         and plats, if any ("Title Review Documents") which will be shown as
         Schedule B Exceptions on the Title Policy upon issuance. Tenant may, at
         Tenant's option and expense, purchase the Title Policy.

         (b) Survey. Landlord shall, within ten (10) days after the Effective
         Date of this Lease, cause to be furnished to Tenant an on-the-ground
         survey ("Survey") of the Land, prepared by a registered surveyor
         reasonably acceptable to Tenant.

         (c) Environmental Report. Landlord shall, within ten (10) days after
         the Effective Date of this Lease, cause to be furnished to Tenant Phase
         I environmental site assessment of the Land which is dated not earlier
         than thirty (30) days prior to the Effective Date of this Lease, which
         is specifically addressed to Tenant and which is in form reasonably
         acceptable to Tenant (the "Environmental Report").

         (d) Objections. On or before five (5) business days after the date on
         which the Commitment, the Title Review Documents, the Survey and the
         Environmental Report have all been delivered to Tenant, Tenant shall
         provide Landlord with written notice of any objection to the Land. If
         Tenant has objections to the Land, Tenant shall have the right to
         terminate this Lease in such notice of objection.

Section 13.07 Covenants of Landlord

         Landlord covenants and agrees that, during the Lease Term:

         (a) Neither Landlord nor any entity which is affiliated with Landlord
         or which has any substantial commonality of ownership with Landlord
         will lease space within any building in the Terrace P.U.D. which is
         occupied 50% or more by Tenant, to any competitor of Tenant. As used
         herein the term "competitor" shall mean any business which is engaged



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         in the design, manufacture and/or sale of semi-conductors and any
         business which provides semi-conductor services, such as electronic
         design automation software.

         (b) Landlord will not enter into or grant any liens on the Land, except
         in connection with any financing or refinancing of the Building
         pursuant to which an SNDA is provided to Tenant under the terms and
         provisions of Section 12.04 of this Lease.

         (c) Landlord will not enter into any leases, contracts or agreement of
         any kind or nature which would be binding upon Tenant or which would
         affect Tenant's rights under this Lease without the prior written
         approval of Tenant.

         (d) Landlord will immediately upon obtaining notice of same, notify
         Tenant of any foreclosure proceeding instituted or proposed with
         respect to the Building or any portion thereof.

         (e) Landlord agrees, upon Tenant's request, to execute and deliver to
         Tenant a memorandum of this Lease which Tenant may record at its
         expense in any real property records or other public records. The
         provisions of this Lease shall control, however, in regard to any
         omissions from the memorandum of lease or any provisions hereof which
         may be in conflict with the memorandum of lease.

         (f) Landlord will not grant any easements, rights of way or other
         encumbrances on the Land which will materially interfere with Tenant's
         use of the Building or Land, other than a Joint Use Agreement in form
         approved by Landlord and Tenant which relates to ingress and egress to
         the land upon which Building VI may be constructed, as described on
         Attachment 1 to Exhibit I ("Building VI"), and easements for utilities
         which service the Building and/or Building VI, provided the location of
         such easements and the form of all easement documents are approved by
         Landlord and Tenant. Landlord and Tenant each agrees not to
         unreasonably withhold or delay approval of such easements, rights of
         way or encumbrances.

Section 13.08 Entry by Landlord

         Due to the confidential nature of the work being performed within the
         Leased Premises, Tenant may control access of third parties to the
         Leased Premises. Notwithstanding any provision in this Lease to the
         contrary, it is expressly agreed and understood that, except in the
         event of an emergency or in connection with janitorial services, access
         to the Leased Premises by Landlord or by any person operating by,
         through or under Landlord will be allowed only upon reasonable prior
         written notice to Tenant and only if each person who enters the Leased
         Premises on behalf of Landlord or on behalf of any entity operating by,
         through or under Landlord is accompanied by a representative of the
         Tenant.

Section 13.09 Tenant's Purchase Option

         Provided no uncured Event of Default on the part of Tenant exists at
         the time of Tenant's exercise of the purchase option hereunder, and
         provided that Tenant has leased all of the Building, Tenant shall have
         the right and option to purchase the Building by providing written
         notice of Tenant's exercise of such option to Landlord at any time
         within twelve (12) months following the Commencement Date. The closing
         of the sale and purchase



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<PAGE>   55




         shall occur within one hundred twenty (120) days after Tenant's
         delivery of notice of exercise of the purchase option to Landlord. At
         the closing: (i) there shall be no uncured Event of Default by Landlord
         under this Lease, and Landlord shall deliver to Tenant a special
         warranty deed conveying the Building to Tenant free and clear of all
         liens and encumbrances, subject only to title exceptions approved by
         Tenant, which are not related to liens or encumbrances; (ii) Tenant
         will pay to Landlord, in readily available funds, a purchase price
         determined by dividing the annual amount of Base Rent under this Lease
         by .095 (for example, if the annual Base Rent under this Lease is
         $4,753,920.00, then the purchase price will be $50,041,263.00); (iii)
         Landlord will pay for an owner's policy of title insurance to be
         delivered to Tenant in the amount of the purchase price, subject only
         to the permitted exceptions approved by Tenant; (iv) this Lease will be
         terminated insofar as it relates to the Building and the Security will
         be returned to Tenant, but all expansion options, rights of first
         refusal and other matters under this Lease not relating to the Building
         shall remain in full force and effect, and Landlord and Tenant will
         enter into an amendment to this Lease to document such matters; (v)
         Landlord will assign and deliver to Tenant all construction plans and
         specifications, engineering reports, environmental reports, technical
         reports, drawings, surveys, utility studies, market studies, appraisals
         and/or other reports or data covering or relating to the Building which
         are in Landlord's possession or which may be obtained by Landlord
         without additional expense; all of Landlord's right, title and interest
         in and to all warranties, guaranties and indemnities relating to the
         Building and all claims thereunder; all of Landlord's right, title and
         interest in and to all approvals, permits, licenses and/or applications
         of any kind or nature which have been issued by or which are on file
         with any governmental agencies, departments or authorities with respect
         to the Building, including without limitation, all zoning approvals,
         subdivision approvals, special permit approvals, site development
         permits, building permits and/or certificates of occupancy and an
         allocation of peak hour trips (relating to vehicle traffic capacity),
         wastewater capacity and impervious cover adequate to accommodate the
         needs of the Building; all water, wastewater, electric, gas, cable
         television, telephone and other utility service rights, permits and/or
         applications relating to or benefitting the Building, including,
         without limitation, all utility taps, utility commitments and/or
         utility meters; all of Landlord's right, title and interest in and to
         all off-site water lines, wastewater lines and other lines, facilities
         or improvements of any kind or nature which provide water, wastewater,
         electric, natural gas, cable television, telephone and other services
         to the Building and all rights of reimbursement for expended costs or
         costs to be incurred in the future arising from or relating to any such
         improvements; all of Landlord's right, title and interest in and to any
         and all off-site street and drainage improvements of any kind or nature
         which provide roadway access or drainage service to the Building; and
         all intangible property of any kind or nature owned or held by Landlord
         in connection with the Building, including without limitation, all
         indemnities or claims which Landlord may have with respect to the
         Building; (vi) all expenses relating to the Building will be prorated
         between Landlord and Tenant and any sums which have been previously
         delivered by Tenant to Landlord to pay for or establish reserves for
         the payment of anticipated ad valorem taxes and/or any other
         anticipated expenses which are not yet due or payable will be refunded
         by Landlord to Tenant; and (vii) Landlord and Tenant shall execute a
         property management agreement in a form reasonably acceptable to both
         Landlord and Tenant, pursuant to which Landlord will provide property
         management services for a period of not less than five (5) years from
         the date of closing for compensation equivalent to the management fee
         referenced in subpart (xii) of Section 3.02(a) hereinabove. Tenant may



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<PAGE>   56
         assign its purchase option under this Lease to a third party without
         the prior written consent of Landlord provided Tenant (or an entity
         which is an affiliate or related to Tenant) remains as an occupant of
         the Building.

13.10 Joint Approval of Press Releases

         Landlord and Tenant acknowledge there will be requests and other
         opportunities to announce Landlord and Tenant entering into this Lease.
         Landlord and Tenant agree to either jointly issue a press release, or
         prior to individually issuing any press release, to provide the other
         party a draft of such release with a reasonable time in which to
         comment. Landlord and Tenant agree to each use reasonable efforts to
         accommodate the requests and comments of the other party in regard to
         the press releases.

                     ARTICLE XIV - EXHIBITS AND ATTACHMENTS

         The following exhibits and attachments are attached to and made a part
         of this Lease: Exhibit A [Land], Exhibit B [Leased Premises], Exhibit C
         [Base Building Design Criteria], Exhibit D [Building Rules and
         Regulations], Exhibit E [Insurance Requirements], Exhibit F [Estoppel
         Certificate], Exhibit G [Subordination, Attornment and Non-Disturbance
         Agreement], Exhibit H [Option to Extend Lease Term], Exhibit I
         [Expansion in Building VI], Exhibit J [Option for Expansion in Building
         VII], Exhibit K [Option for Expansion in Building II], Exhibit L
         [Tri-Party Agreement], and Exhibit M [Tenant Work Letter] and Exhibit N
         [Letter of Credit]. All of the terms and provisions in the attached
         exhibits and attachments are hereby incorporated into this Lease as if
         the same were set forth herein verbatim.

         This Lease is executed in multiple originals as of the Effective Date.




LANDLORD:                                   DESTA FIVE PARTNERSHIP, LTD.,
                                            a Texas limited partnership

                                      By: DESTA FIVE DEVELOPMENT CORP., a
                                          Texas corporation, its general partner



                                             By:
                                                  L. Paul Latham, President



TENANT:                                      CIRRUS LOGIC, INC.



                                             By:


                                             Name:
                                                   -----------------------------

                                             Title:



                                       56
<PAGE>   57


GUARANTOR:                                  W&G PARTNERSHIP, LTD.,
(Pursuant to the provisions of Section      a Texas limited partnership
12.23 only)

                                       By:  ClayDesta, L.P., a Texas limited
                                            partnership, its general partner


                                       By:  CLAYDESTA OPERATING, L.L.C., a Texas
                                            limited liability company, its
                                            general partner



                                            By:
                                                 L. Paul Latham, President







EXHIBITS AND ATTACHMENTS:

Exhibit A:   Land
Exhibit B:   Leased Premises
Exhibit C:   Base Building Design Criteria
Exhibit D:   Building Rules and Regulations
Exhibit E:   Insurance Requirements
Exhibit F:   Estoppel Certificate
Exhibit G:   Subordination, Attornment and Non-Disturbance Agreement
Exhibit H:   Option to Extend Lease Term
Exhibit I:   Expansion in Building VI
Exhibit J:   Option for Expansion in Building VII
Exhibit K:   Option for Expansion in Building II
Exhibit L:   Tri-Party Agreement
Exhibit M:   Tenant Work Letter
Exhibit N:   Letter of Credit



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