<PAGE>

                                                                   Exhibit 10.18

                    * * * * * * * * * * * * * * * * * * * *


                                LEASE AGREEMENT


                                    BETWEEN


                Prentiss Properties Acquisition Partners, L.P.
                        a Delaware limited partnership

                                  (Landlord)


                                      AND


                             Vignette Corporation,
                            a Delaware corporation


                                   (Tenant)


                               Two Barton Skyway
                         1601 South Mo-Pac Expressway
                                 Austin, Texas


                             Dated: March 3, 2000


                    * * * * * * * * * * * * * * * * * * * *
<PAGE>

                      TABLE OF CONTENTS - LEASE AGREEMENT

<TABLE>
<CAPTION>
                                                                             PAGE
<S>                                                                          <C>
ARTICLE 1   BASIC LEASE INFORMATION AND CERTAIN DEFINITIONS...................  1

ARTICLE 2   PREMISES AND QUIET ENJOYMENT......................................  2

ARTICLE 3   TERM; COMMENCEMENT DATE; DELIVERY; ACCEPTANCE OF PREMISES.........  2

ARTICLE 4   RENT..............................................................  3

ARTICLE 5   OPERATING COSTS...................................................  3

ARTICLE 6   PARKING...........................................................  6

ARTICLE 7   SERVICES OF LANDLORD..............................................  6

ARTICLE 8   ASSIGNMENT AND SUBLETTING.........................................  7

ARTICLE 9   REPAIRS...........................................................  8

ARTICLE 10  ALTERATIONS.......................................................  9

ARTICLE 11  LIENS............................................................. 10

ARTICLE 12  USE AND COMPLIANCE WITH LAWS...................................... 10

ARTICLE 13  DEFAULT AND REMEDIES.............................................. 10

ARTICLE 14  INSURANCE......................................................... 11

ARTICLE 15  DAMAGE BY FIRE OR OTHER CAUSE..................................... 12

ARTICLE 16  CONDEMNATION...................................................... 12

ARTICLE 17  INDEMNIFICATION................................................... 13

ARTICLE 18  SUBORDINATION AND ESTOPPEL CERTIFICATES........................... 13

ARTICLE 19  SURRENDER OF THE PREMISES......................................... 14

ARTICLE 20  LANDLORD'S RIGHT TO INSPECT....................................... 14

ARTICLE 21  SECURITY DEPOSIT.................................................. 15

ARTICLE 22  BROKERAGE......................................................... 15

ARTICLE 23  OBSERVANCE OF RULES AND REGULATIONS............................... 15

ARTICLE 24  NOTICES........................................................... 15

ARTICLE 25  MISCELLANEOUS..................................................... 16

ARTICLE 26  INTENTIONALLY DELETED............................................. 17

ARTICLE 27  OTHER DEFINITIONS................................................. 17
</TABLE>

                                       I
<PAGE>

                              EXHIBITS AND RIDERS

     The following Exhibits and Riders are attached hereto and by this reference
made a part of this Lease:

EXHIBIT A      -     FLOOR PLAN OF THE PREMISES

EXHIBIT B      -     THE LAND

EXHIBIT C      -     LEASEHOLD IMPROVEMENTS

EXHIBIT D      -     FORM OF COMMENCEMENT NOTICE

RIDER NO. 1    -     RULES AND REGULATIONS

RIDER NO 2           EXTENSION OPTION

                                      II
<PAGE>

                            INDEX OF DEFINED TERMS

     Definitions of certain terms used in this Lease are found in the following
sections:

<TABLE>
<CAPTION>
TERM                                                            LOCATION OF DEFINITION
<S>                                                             <C>
Additional Rent                                                          Section 1.01N
Bankruptcy Code                                                           Section 8.06
Base Premises Condition                                                      Exhibit C
Base Rent                                                                Section 1.01M
Base Year Operating Costs                                                Section 1.01O
Basic Lease Information and Certain Definitions                              Article 1
Branch                                                                       Exhibit C
Broker                                                                   Section 1.01W
Building                                                                 Section 1.01B
Building Standard                                                            Exhibit C
Business Days                                                               Article 27
Central                                                                      Exhibit C
Commencement Date                                                        Section 1.01F
Common Areas                                                                Article 27
days                                                                        Article 27
Events of Default                                                        Section 13.01
Expiration Date                                                          Section 1.01G
herein, hereof, hereby, hereunder and words
  of similar import                                                         Article 27
include and including                                                       Article 27
Interest Rate                                                             Section 4.02
Land                                                                     Section 1.01C
Landlord                                                                      Preamble
Landlord's Address for Notice                                            Section 1.01T
Landlord's Address for Payment                                           Section 1.01U
Landlord's Operating Costs Estimate                                       Section 5.01
Leasehold Improvements                                                       Exhibit C
Net Rentable Area                                                           Article 27
Net Rentable Area of the Building                                        Section 1.01J
Net Rentable Area of the Premises                                        Section 1.01I
Non-Building Standard                                                        Exhibit C
Parking Facilities                                                       Section 1.01D
Parking Permits                                                          Section 1.01P
Permit Fees                                                              Section 1.01P
Project                                                                  Section 1.01E
Premises                                                                 Section 1.01A
Reference to Landlord as having "no liability
  to Tenant" or being" without liability to
  Tenant" or words of like import                                           Article 27
Rent                                                                     Section 1.01L
repair                                                                      Article 27
Security Deposit                                                         Section 1.01R
Successor Landlord                                                       Section 18.02
Taxes                                                                     Section 5.02
Tenant                                                           Preamble & Article 27
Tenant Delay                                                                 Exhibit C
Tenant's Address for Notice                                              Section 1.01V
Tenant's Allowance                                                           Exhibit C
Tenant's Permitted Uses                                                  Section 1.01Q
Tenant's Property                                                    Section 14.01A(a)
Tenant's Share                                                           Section 1.01K
Tenant's Work                                                                Exhibit C
Term                                                                     Section 1.01H
termination of this Lease and words of like import                          Article 27
terms of this Lease                                                         Article 27
this Lease                                                                    Preamble
year                                                                        Article 27
</TABLE>

                                       i
<PAGE>

                                LEASE AGREEMENT

     THIS LEASE AGREEMENT ("this Lease") is made and entered into by and between
Prentiss Properties Acquisition Partners, L.P., a Delaware limited partnership
("Landlord") and Vignette Corporation, a Delaware corporation ("Tenant"), upon
all the terms set forth in this Lease and in all Exhibits and Riders hereto, to
each and all of which terms Landlord and Tenant hereby mutually agree, and in
consideration of One Dollar ($1.00) and other valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, and of the rents,
agreements and benefits flowing between the parties hereto, as follows:

                                   ARTICLE 1

                BASIC LEASE INFORMATION AND CERTAIN DEFINITIONS

     1.01.  Each reference in this Lease to information and definitions
contained in the Basic Lease Information and Certain Definitions and each use of
the terms capitalized and defined in this Section 1.01 shall be deemed to refer
to, and shall have the respective meaning set forth in, this Section 1.01.

     A.     Premises:                   The portion of the first and second
                                        floors of the Building, as said space is
                                        identified by diagonal lines on the
                                        floor plans attached hereto as Exhibit
                                                                       -------
                                        A.
                                        -

     B.     Building:                   The four (4) story office building owned
                                        by Landlord on the Land generally
                                        located at 1601 South Mo-Pac Expressway,
                                        Austin, Texas.

     C.     Land:                       That certain parcel of land described
                                        under the caption "Land" in Exhibit B
                                                                    ---------
                                        hereof.

     D.     Parking Facilities:         The parking garage which is located
                                        adjacent to the Building, together with
                                        all surface parking areas located or to
                                        be located on the Land.

     E.     Project:                    The Land and all improvements thereon,
                                        including the Building, the Parking
                                        Facilities, and all Common Areas.

     F.     Commencement Date:          That certain date on which the Term
                                        shall commence, as determined pursuant
                                        to the provisions of Article 3 hereof.

     G.     Expiration Date:            The last day of the calendar month in
                                        which the fifth (5th) anniversary of the
                                        Commencement Date occurs.

     H.     Term:                       Approximately five (5) years, beginning
                                        on the Commencement Date and ending at
                                        11:59 p.m. on the Expiration Date,
                                        unless this Lease is sooner terminated
                                        as provided herein.

     I.     Net Rentable Area of the
            Premises:                   48,386 square feet.

     J.     Net Rentable Area of the
            Building:                   Approximately 195,821 square feet.

     K.     Tenant's Share:             24.71%, representing a fraction, the
                                        numerator of which is the Net Rentable
                                        Area of the Premises and the denominator
                                        of which is the Net Rentable Area of the
                                        Building, subject to future adjustment
                                        pursuant to the provisions of Section
                                        5.04 hereof.

     L.     Rent:                       The Base Rent and the Additional Rent.

     M.     Base Rent:                  The Base Rent shall be $919,334.00 per
                                        annum ($19.00 per square foot per annum
                                        of Net Rentable Area of the Premises).

     N.     Additional Rent:            The Additional Rent shall be Tenant's
                                        Operating Costs Payment and all other
                                        sums due and payable by Tenant under the
                                        Lease.

     O.     Landlord's Operating
            Costs Estimate:             The estimate for the calendar year 2000
                                        of the Term is $476,602.10 per annum
                                        ($9.85 per square foot of Net Rentable
                                        Area of the Premises).

     P.     Parking Spaces:             Tenant shall be entitled to take 188
                                        unassigned Parking Spaces and 5 reserved
                                        Parking Spaces in the garage, at no
                                        charge during the initial Term.

                                       1
<PAGE>

     Q.     Tenant's Permitted Uses:    Tenant may use the Premises for
                                        executive and administrative offices for
                                        the conduct of Tenant's business and for
                                        no other purpose.

     R.     Security Deposit:           [To be determined].

     S.     Broker:                     Colliers Oxford Commercial Inc./Colliers
                                        Cauble & Company

     T.     Landlord's Address for
            Notice:                     Prentiss Properties Acquisition
                                        Partners, L.P.
                                        3890 West Northwest
                                        Highway, Suite 400
                                        Dallas, Texas 75220
                                        Attention: Michael V. Prentiss
                                        Telecopy No.: (214) 350-2408

            with copies to:             Prentiss Properties Acquisition
                                        Partners, L.P.
                                        3860 West Northwest Highway, Suite 400
                                        Dallas, Texas 75220
                                        Attention: Dennis J. DuBois
                                        Telecopy No.: (214) 358-7122

     U.     Landlord's Address for
            Payment:                    Prentiss Properties Acquisition
                                        Partners, L.P.
                                        3890 West Northwest Highway, Suite 400
                                        Dallas, Texas 75220

     V.     Tenant's Address for
            Notice:                     901 South MoPac, Building III
                                        Austin, Texas 78746
                                        Telecopy No.: (512) 306-4500

                                   ARTICLE 2

                         PREMISES AND QUIET ENJOYMENT

     2.01.  Landlord hereby leases the Premises to Tenant, and Tenant hereby
rents and leases the Premises from Landlord, for the Term. During the Term,
Tenant shall have the right to use, in common with others and in accordance with
the Rules and Regulations, the Common Areas.

     2.02.  Provided that Tenant fully and timely performs all the terms of this
Lease on Tenant's part to be performed, including payment by Tenant of all Rent,
Tenant shall have, hold and enjoy the Premises during the Term without hindrance
or disturbance from or by Landlord; subject, however, to all of the terms,
conditions and provisions of any and all ground leases, deeds to secure debt,
mortgages, governmental laws, easements, protective covenants, and other
encumbrances now or hereafter affecting the Premises, or the Project.

                                   ARTICLE 3

                           TERM; COMMENCEMENT DATE;
                       DELIVERY; ACCEPTANCE OF PREMISES

     3.01.  The Commencement Date shall be the earliest of (a) sixty (60) days
following the delivery of the Premises in Base Premises Condition (as defined in
Exhibit C to the Lease), (b) the date the Premises are deemed available for
---------
occupancy pursuant to Section 3.02 hereof or (c) the date Tenant, or anyone
claiming by, through or under Tenant, occupies any portion of the Premises for
the purpose of the conduct of Tenant's (or such other person's) business
therein.

     3.02.  A. The Premises shall be deemed available for occupancy as soon as
the following conditions have been met: (a) the Leasehold Improvements (as
defined in Exhibit C to the Lease) have been substantially completed as
           ---------
determined by Landlord's architect or space planner (except for the punch list
items described in Section 3.05(c) hereof), or (b) either a certificate or
certificates of occupancy (temporary or final) has been issued for the Premises
by the appropriate governmental authority.

     B.     Notwithstanding anything to the contrary contained herein, if there
is a delay in the availability for occupancy of the Premises due to Tenant Delay
(as defined in Exhibit C to the Lease) then the Premises shall be deemed
               ---------
available for occupancy on the date on which the Premises would have been
available for occupancy but for such Tenant Delay, even though a certificate of
occupancy or other certificate permitting the lawful occupancy of the Premises
has not been issued or the Leasehold Improvements have not been commenced or
completed.

     C.     Subject to events of force majeure (as described in Section 25.06 of
this Lease), Landlord shall cause the Premises to be made available to Tenant in
Base Premises Condition by September 1, 2000 (such date, as it may be extended
as a result of events of force majeure, being herein called the "Base Premises
Condition Completion Date"). In the event Landlord fails to cause the Premises
to be made available to Tenant in Base Premises Condition by the Base Premises
Condition Completion Date, Tenant shall so notify Landlord in writing (the "Base
Premises Condition Default Notice"), and, if Landlord fails to cause the
Premises to be made available to Tenant in Base Premises Condition within thirty
(30) days following Landlord's receipt of the Base Premises Condition Default
Notice (such date being herein called the "Required Base Condition Cure Date"),
then the

                                       2
<PAGE>

commencement of the payment of Base Rent and Additional Rent shall be delayed
for one (1) day for each day following the Required Base Condition Cure Date
until the date Landlord actually causes the Premises to be made available to
Tenant in Base Premises Condition. The certification by Landlord's architect of
the occurrence of Base Premises Condition shall be binding on the Landlord and
Tenant.

     3.03.  The Net Rentable Area of the Premises and the Building are
approximately as stated in Sections 1.01I and J, respectively. By written
instrument substantially in the form of Exhibit D attached hereto, Landlord
                                        ---------
shall notify Tenant of the Commencement Date, the Net Rentable Area of the
Premises and all other matters stated therein. The Commencement Notice shall be
conclusive and binding on Tenant as to all matters set forth therein, unless
within five (5) days following delivery of such Commencement Notice, Tenant
contests any of the matters contained therein by notifying Landlord in writing
of Tenant's objections. The foregoing notwithstanding, Landlord's failure to
deliver any Commencement Notice to Tenant shall not affect Landlord's
determination of the Commencement Date.

     3.04.  Tenant may not enter or occupy the Premises prior to the
Commencement Date without Landlord's express written consent and any entry by
Tenant shall be subject to all of the terms of this Lease; provided however,
that no such early entry shall change the Commencement Date or the Expiration
Date. Prior to the Commencement Date, Tenant, its agents and contractors may
enter the Premises strictly for purposes of placing and securing Tenant's
"built-in" furniture and installing Tenant's computer equipment, telephone
equipment and other office equipment in the Premises so long as Tenant does not
unreasonably interfere with the activities of the contractors installing the
Leasehold Improvements.

     3.05.  Occupancy of the Premises or any portion thereof by Tenant or anyone
claiming through or under Tenant for the conduct of Tenant's, or such other
person's business therein shall be conclusive evidence that Tenant and all
parties claiming through or under Tenant (a) have accepted the Premises as
suitable for the purposes for which the Premises are leased hereunder, (b) have
accepted the Common Areas as being in a good and satisfactory condition and (c)
with the exception of punchlist items that Landlord's Manager (as defined in
Exhibit C) will use reasonable efforts to cause Tenant's Contractor (as defined
---------
in Exhibit C) to remedy as soon as reasonably practicable, have waived any
   ---------
defects in the Premises and the Project. Except as otherwise expressly provided
herein, Landlord shall have no liability, except for gross negligence or willful
misconduct, to Tenant or any of Tenant's agents, employees, licensees, servants
or invitees for any injury or damage to any person or property due to the
condition or design of, or any defect in, the Premises or the Project, including
any electrical, plumbing or mechanical systems and equipment of the Premises or
the Project and the condition of or any defect in the Land; and Tenant, for
itself and its agents, employees, licensees, servants and invitees, expressly
assumes all risks of injury or damage to person or property, either proximate or
remote, resulting from the condition of the Premises or the Project.

                                   ARTICLE 4

                                     RENT

     4.01.  Tenant shall pay to Landlord, without notice, demand, offset or
deduction, in lawful money of the United States of America, at Landlord's
Address for Payment, or at such other place as Landlord shall designate in
writing from time to time: (a) the Base Rent in equal monthly installments, in
advance, on the first day of each calendar month during the Term, and (b) the
Additional Rent, at the respective times required hereunder. The first monthly
installment of Base Rent and Tenant's Operating Costs Payment payable under
Article 5 hereof shall be paid in advance on the date of Tenant's execution of
this Lease and applied to the first installments of Base Rent and Tenant's
Operating Costs Payment coming due under this Lease. Payment of Rent shall begin
on the Commencement Date; provided, however, that, if either the Commencement
Date or the Expiration Date falls on a date other than the first day of a
calendar month, the Rent due for such fractional month shall be prorated on a
per diem basis between Landlord and Tenant so as to charge Tenant only for the
portion of such fractional month falling within the Term.

     4.02.  All installments of Rent not paid within five (5) days of the date
when due shall bear interest from the date when due until paid at a rate per
annum (the "Interest Rate") equal to the greater of fifteen percent (15%) or
four percent (4%) above the prime rate of interest from time to time publicly
announced by Bank One, Texas, N.A., or any successor thereof; provided, in no
event shall such interest rate exceed the maximum rate permitted under federal
law or under the laws of the State of Texas, whichever law permits the greater
rate.

                                   ARTICLE 5

                                OPERATING COSTS

     5.01.  Tenant shall pay to Landlord, as Additional Rent, for each year or
fractional year during the Term an amount ("Tenant's Operating Costs Payment")
of money equal to Tenant's Share of Operating Costs, as hereinafter defined, for
such year, such amount to be calculated and paid as follows:

            (a)  On the first day of January of each year during the Term (or,
with respect to the year in which the Commencement Date occurs, prior to the
Commencement Date), or as soon there-after as is practicable, Landlord shall
furnish Tenant with a statement ("Landlord's Operating Costs Estimate") setting
forth Landlord's reasonable estimate of Operating Costs for the forth-coming
year (or the fractional year in which the Commencement Date occurs, as the case
may be). On the first day of each calendar month during such year, Tenant shall
pay to Landlord one-twelfth of Tenant's Operating Costs Payment as estimated on
Landlord's Operating Costs Estimate. If for any reason Landlord has not provided
Tenant with Landlord's Operating Costs Estimate on the first

                                       3
<PAGE>

day of January of any year during the Term (or by the Commencement Date, as the
case may be), then, (i) until the first day of the calendar month following the
month in which Tenant is given Landlord's Estimate of Operating Costs, Tenant
shall continue to pay to Landlord on the first day of each calendar month the
monthly sum, if any, payable by Tenant under this Section 5.01 for the month of
December of the preceding year, and (ii) promptly after Landlord's Operating
Costs Estimate is furnished to Tenant or together therewith, Landlord shall give
notice to Tenant stating whether the installments of Tenant's Operating Costs
Payments previously made for such year were greater or less than the
installments of Tenant's Operating Costs Payments to be made for such year in
accordance with Landlord's Operating Costs Estimate, and (A) if there shall be a
deficiency, Tenant shall pay the amount thereof to Landlord within fifteen (15)
days after the giving of Landlord's Operating Costs Estimate, or (B) if there
shall have been an overpayment, Landlord shall apply such overpayment as a
credit against the next accruing installment(s) of Additional Rent due from
Tenant under this Section 5.01 until fully credited to Tenant, and (C) on the
first day of the first calendar month following the month in which Tenant is
given Landlord's Estimate of Operating Costs and on the first day of each
calendar month thereafter during the Term throughout the remainder of such year,
Tenant shall pay to Landlord an amount equal to one-twelfth (1/12th) of Tenant's
Operating Costs Payment. The foregoing notwithstanding, Landlord shall have the
right from time to time during any year to notify Tenant in writing of any
change in Landlord's Operating Costs Estimate, in which event such Tenant's
Operating Costs Payment, as previously estimated, shall be adjusted to reflect
the amount shown in such notice and shall be effective, and due from Tenant, on
the first day of each month during the year for which given following Landlord's
giving of such notice.

            (b)  On the first day of March of each year during the Term
(beginning on the first day of March of the year following the year in which the
Commencement Date occurs), or as soon thereafter as is practicable, Landlord
shall furnish Tenant with a statement of the actual Operating Costs for the
preceding year. Within thirty (30) days after Landlord's delivery of such
statement, Tenant shall make a lump sum payment to Landlord in the amount, if
any, by which Tenants' Operating Costs Payment for such preceding year as shown
on such Landlord's statement, exceeds the aggregate of the monthly installments
of Tenant's Operating Costs Payments paid during such preceding year. If
Tenant's Operating Costs Payment, as shown on such Landlord's statement, is less
than the aggregate of the monthly installments of Tenant's Operating Costs
Payment actually paid by Tenant during such preceding year, then Landlord shall
apply such amount to the next accruing installment(s) of Additional Rent due
from Tenant under this Section 5.01 until fully credited to Tenant.

            (c)  If the Commencement Date occurs on a date other than the first
day of January, or if the Term ends on a date other than the last day of
December, the actual Operating Costs for the year in which the Commencement Date
or the Expiration Date occurs, as the case may be, shall be prorated so that
Tenant shall pay that portion of Tenant's Share of Operating Costs for such year
represented by a fraction, the numerator of which shall be the number of days
during such fractional year falling within the Term, and the denominator of
which is 365 (or 366, in the case of a leap year). The provisions of this
Section 5.01 shall survive the Expiration Date or any sooner termination
provided for in this Lease.

     5.02.  For purposes of this Lease, the term "Operating Costs" shall mean
any and all expenses, costs and disbursements of every kind which Landlord pays,
incurs or becomes obligated to pay in connection with the operation, management,
repair and maintenance of all portions of the Project. All Operating Costs shall
be determined according to generally accepted accounting principles which shall
be consistently applied. Operating Costs include, but are not limited to, the
following:

            (a)  Wages, salaries, and fees (including, but not limited to, all
reasonable educational, travel and professional fees) of all personnel or
entities (exclusive of Landlord's executive personnel) engaged in the operation,
repair, maintenance, or security of the Project, including taxes, insurance, and
benefits relating thereto and the costs of all supplies and materials (including
work clothes and uniforms) used in the operation, repair, and maintenance or
security of the Project.

            (b)  Cost of performance by Landlord's personnel of, or of all
service agreements for, maintenance, janitorial services, access control, alarm
service, window cleaning, elevator maintenance and landscaping for the Project.
The foregoing project shall include rental of personal property used by
Landlord's personnel in the maintenance and repair of the Project.

            (c)  All utilities for the Project, including water, sewer, power,
electricity, gas, fuel, lighting and all other utilities; and all air-
conditioning, heating and ventilating costs for the Project.

            (d)  Cost of all insurance, including casualty and liability
insurance applicable to the Project and to Landlord's equipment, fixtures and
personal property used in connection therewith, business interruption or rent
insurance against such perils as are commonly insured against by prudent
landlords, such other insurance as may be required by any lessor or mortgagee of
Landlord and such other insurance which Landlord considers reasonably necessary
in the operation of the Project, together with all appraisal and consultants'
fees in connection with such insurance.

            (e)  All Taxes. For purposes hereof, the term "Taxes" shall mean (i)
all taxes, assessments, and other governmental charges, applicable to or
assessed against the Project or any portion thereof, or applicable to or
assessed against Landlord's personal property used in connection therewith,
whether federal, state, county, or municipal and whether assessed by taxing
districts or authorities presently taxing the Project or the operation thereof
or by other taxing authorities subsequently created, or otherwise, and any other
taxes and assessments attributable to or assessed against all or any part of the
Project or its operation, and (ii) any reasonable expenses, including fees and
disbursements of attorneys, tax consultants, arbitrators, appraisers, experts
and other witnesses, incurred by Landlord in contesting any taxes or the
assessed valuation of all or any part of the Project. If at any time during the

                                       4
<PAGE>

Term there shall be levied, assessed, or imposed on Landlord or all or any part
of the Project by any governmental entity any general or special ad valorem or
other charge or tax directly upon rents received under leases, or if any fee,
tax, assessment, or other charge is imposed which is measured by or based, in
whole or in part, upon such rents, or if any charge or tax is made based
directly or indirectly upon the transactions represented by leases or the
occupancy or use of the Project or any portion thereof, such taxes, fees,
assessments or other charges shall be deemed to be Taxes; provided, however,
that any (i) franchise, corporation, income or net profits tax, unless
substituted for real estate taxes or imposed as additional charges in connection
with the ownership of the Project, which may be assessed against Landlord or the
Project or both, (ii) transfer taxes assessed against Landlord or the Project or
both, (iii) penalties or interest on any late payments of Landlord, and (iv)
personal property taxes of Tenant or other tenants in the Project shall be
excluded from Taxes. If any or all of the Taxes paid hereunder are by law
permitted to be paid in installments, notwithstanding how Landlord pays the
same, then, for purposes of calculating Operating Costs, such Taxes shall be
deemed to have been divided and paid in the maximum number of installments
permitted by law, and there shall be included in Operating Costs for each year
only such installments as are required by law to be paid within such year,
together with interest thereon and on future such installments as provided by
law.

            (f)  Legal and accounting costs incurred by Landlord or paid by
Landlord to third parties (exclusive of legal fees with respect to disputes with
individual tenants, negotiations of tenant leases, or with respect to the
ownership rather than the operation of the Project), appraisal fees, consulting
fees, all other professional fees and disbursements and all association dues.

            (g)  Cost of non-capitalized repairs and general maintenance of the
Project (excluding repairs and general maintenance paid by proceeds of insurance
or by Tenant, other tenants of the Project or other third parties).

            (h)  Amortization of the cost of improvements or equipment which are
capital in nature and which (i) are for the purpose of reducing Operating Costs
of the Project, up to the amount saved as a result of the installation thereof,
as reasonably estimated by Landlord, or (ii) enhance the Project for the general
benefit of tenants or occupants thereof, or (iii) are required by any
governmental authority, or (iv) replace any building equipment needed to operate
the Project at the same quality levels as prior to the replacement. All such
costs, including interest, shall be amortized on a straight-line basis over the
useful life of the capital investment items, as reasonably determined by
Landlord, but in no event beyond the reasonable useful life of the Project as a
first class office project.

            (i)  Project management office rent or rental value.

            (j)  A management fee (whether or not Landlord engages a manager for
the Project) and all items reimbursable to the Project manager, if any, pursuant
to any management contract for the Project Landlord currently pays a management
fee equal to three percent (3%) of the gross receipts from the Project and all
items reimbursable to the Project manager pursuant to its management contract.
Landlord agrees that any future increase in the management fee payable by
Landlord shall not exceed management fees customarily paid at the time by other
landlords of first class office buildings in the Austin suburban area.

            (k)  Amounts payable pursuant to the restrictive covenants affecting
the Project, if any, as amended from time to time.

            "Operating Costs" shall not include (i) specific costs for any
capital repairs, replacements or improvements, except as provided above; (ii)
expenses for which Landlord is reimbursed or indemnified (either by an insurer,
condemnor, tenant, warrantor or otherwise) to the extent of funds received by
Landlord; (iii) expenses incurred in leasing or procuring tenants (including
lease commissions, advertising expenses and expenses of renovating space for
tenants); (iv) payments for rented equipment, the cost of which would constitute
a capital expenditure not permitted pursuant to the foregoing if the equipment
were purchased; (v) interest or amortization payments on any mortgages; (vi) net
basic rents under ground leases; (vii) costs representing an amount paid to an
affiliate of Landlord which is in excess of the amount which would have been
paid in the absence of such relationship; (viii) wages, salaries or other
compensation paid for clerks or attendants in concessions or news stands
operated in the Project; (ix) the cost of installing, maintaining and operating
any specialty service such as an observatory, broadcasting facility, luncheon
club or an athletic or recreational club; or (x) costs specially billed to and
paid by specific tenants. There shall be no duplication of costs or
reimbursement.

     5.03.  If the Building is not 95% occupied (meaning ninety-five percent
(95%) of the Net Rentable Area of the Building) during any full or fractional
year of the Term, the actual Operating Costs shall be adjusted for such year to
an amount which Landlord estimates would have been incurred in Landlord's
reasonable judgment had the Building been 95% occupied.

     5.04.  If during the Term any change occurs in either the number of square
feet of the Net Rentable Area of the Premises or of the Net Rentable Area of the
Building, Tenant's Share of Operating Costs shall be adjusted, effective as of
the date of any such change. On and after the date of any such change, Tenant's
Operating Costs Payment pursuant to Section 5.01A shall be adjusted effective as
of the date of such change.

                                       5
<PAGE>

                                   ARTICLE 6

                                    PARKING

     6.01.  Landlord hereby grants to Tenant a license to use in common with
other tenants and with the public, parking spaces in the Parking Facilities.
Each such Tenant shall be entitled to the number of parking spaces in the
Parking Facilities as set forth in Section 1.01. The number of Parking Permits
to be issued to Tenant and the initial monthly Permit Fee for each Parking
Permit is set forth in Section 1.01P. Landlord shall not be obligated to provide
Tenant with any additional Parking Permits. If Tenant fails to observe the Rules
and Regulations with respect to the Parking Facilities, then Landlord, at its
option, shall have the right to terminate Tenant's Parking Permits, without
legal process, and to remove Tenant, Tenant's vehicles and those of its
employees, licensees or invitees and all of Tenant's personal property from the
Parking Facilities.

                                   ARTICLE 7

                             SERVICES OF LANDLORD

     7.01.  A. During the Term, Landlord shall furnish Tenant with the following
services: (a) hot and cold water in Building Standard bathrooms and chilled
water in Building Standard drinking fountains; (b) electrical power sufficient
for lighting the Premises and for the operation therein of typewriters,
voicewriters, calculating machines, word processing equipment, photographic
reproduction equipment, copying machines, personal computers, and similar items
of business equipment which consume, in the aggregate, less than six (6) watts
per square foot of Net Rentable Area of the Premises and require a voltage of
120 volts single phase or less, (c) heating, ventilating or air-conditioning, as
appropriate, during Business Hours; (d) electric lighting for the Common Areas
of the Project; (e) passenger elevator service, in common with others, for
access to and from the Premises twenty-four (24) hours per day, seven (7) day
per week; provided, however, that Landlord shall have the right to limit the
number of (but not cease to operate all) elevators to be operated for repairs
and after Business Hours and on Saturdays, Sundays and Holidays; (f) janitorial
cleaning services; (g) facilities for Tenant's loading, unloading, delivery and
pick-up activities, including access thereto during Business Hours, subject to
the Rules and Regulations; and (h) replacement, as necessary, of all Building
Standard lamps and ballasts in Building Standard light fixtures within the
Premises. All services referred to in this Section 7.01A shall be provided by
Landlord and paid for by Tenant as part of Rent.

            B.   If Tenant requires air-conditioning, heating or other services,
including cleaning services, for hours or days in addition to the hours and days
specified in Section 7.01A, Landlord shall provide such additional service after
reasonable prior written request therefor from Tenant, and Tenant shall
reimburse Landlord for the cost of such additional service. Landlord shall have
no obligation to provide any additional service to Tenant at any time Tenant is
in default under this Lease unless Tenant pays to Landlord, in advance, the cost
of such additional service.

            C.   Tenant shall not install any machinery or equipment which
generates abnormal heat or otherwise creates unusual demands on the air-
conditioning or heating system serving the Premises. Tenant shall not install
any electrical equipment requiring special wiring unless approved in advance by
Landlord. At no time shall use of electricity in the Premises exceed the
capacity of existing feeders and risers to or wiring in the Premises.

            D.   If Tenant's requirements for or consumption of electricity
exceed the capacities specified in Section 7.01A(b) hereof, Landlord shall, at
Tenant's sole cost and expense, bill Tenant periodically for such additional
service. The degree of such additional consumption by Tenant shall be determined
at Landlord's election, by either or both (a) a survey of standard or average
tenant usage of electricity in the Building performed by a reputable consultant
selected by Landlord and paid for by Tenant, and (b) a separate meter in the
Premises to be installed, maintained, and read by Landlord, all at Tenant's sole
cost and expense.

            E.   Landlord shall provide Tenant, in a location in the Project
mutually acceptable to Landlord and Tenant, space for Tenant to install an
emergency generator, at Tenant's sole cost and expense. Tenant shall indemnify
Landlord for any lien, damage, loss, cost, expense and liability incurred as a
result of Tenant's use and operation of such emergency generator.

     7.02.  Landlord's obligation to furnish electrical and other utility
services shall be subject to the rules and regulations of the supplier of such
electricity of other utility services and the rules and regulations of any
municipal or other governmental authority regulating the business of providing
electricity and other utility services.

     7.03.  No failure to furnish, or any stoppage of, the services referred to
in this Article 7 resulting from any cause shall make Landlord liable in any
respect for damages to any person, property or business, or be construed as an
eviction of Tenant, or entitle Tenant to any abatement of Rent or other relief
from any of Tenant's obligations under this Lease. Should any malfunction of any
systems or facilities occur within the Project or should maintenance or
alterations of such systems or facilities become necessary, Landlord shall
repair the same promptly and with reasonable diligence, and Tenant shall have no
claim for rebate, abatement of Rent, or damages because of malfunctions or any
such interruptions in service.

     7.04.  A. Landlord grants to Tenant, at an annual cost of $36,000.00
($18,000.00 per communications antennae or satellite dish), payable in monthly
installments of $3,000.00 each, in addition to and on the same dates as
installments of Base Rent are payable pursuant to Section 4.01 hereof, a
nonexclusive right to install upon the roof of the Building and operate during
the Term up to two (2) communications antennae or satellite dishes and
appurtenant communications equipment (the "Roof Installation").

                                       6
<PAGE>

         B.    The Roof Installation shall not extend above the height of the
roof's parapet wall and shall not affect the appearance of the Building. Prior
to Tenant's installation of any Roof Installation, the specifications of the
Roof Installation then to be installed and the location of their installation on
the roof of the Building shall be approved in writing by Landlord.

         C.    The costs and expenses of acquiring, installing, maintaining and
operating the Roof Installation shall be borne exclusively by Tenant. Tenant
shall indemnify Landlord for any lien, damage, loss, cost, expense and liability
incurred as a result of the Roof Installation (and any related wiring or
conduit) and the operation thereof, and no costs or expenses shall be incurred
by Landlord in connection with Tenant's installation or use of the Roof
Installation.

         D.    The Roof Installation shall be Tenant's sole and exclusive
property, and shall be considered Tenant's movable trade fixtures under Section
10.03 of this Lease.

         E.    Tenant agrees to cause the Roof Installation to comply with all
applicable laws, regulations, and ordinances. Tenant further agrees that its
rights under this Section 7.04 are subject to the rights of Landlord and other
tenants of the Building to install similar equipment, and the obligation of
Landlord to maintain the general appearance of the Project, including the roof-
top of the Building.

         F.    Landlord grants to Tenant during the term of this Lease, at no
additional cost other than as set forth in Section 7.04A above, nonexclusive
rights of access, ingress and egress to, over, across and upon the roof of the
Building and other non-public areas of the Building (excluding space leased or
customarily available for lease to other tenants) to facilitate Tenant's
installation, maintenance, and operation of the Roof Installation. Further,
Landlord grants to Tenant during the Term of this Lease, at no additional cost
other than as set forth in Section 7.04A above, a nonexclusive license to use
shaft and other space in the core service areas of the Building for the
installation and maintenance of cables, wiring and related conduit appurtenant
to the Roof Installation as may be reasonably necessary to facilitate Tenant's
installation, maintenance and operation of the Roof Installation, so long as
such use of shaft and other space in the core service areas of the Building does
not interfere with the operations and maintenance of the Building.

         G.    Tenant agrees to abide by such rules and regulations of Landlord
relating to the Roof Installation and appurtenant rights granted herein as the
Landlord may from time to time prescribe.

         H.    At the request of Landlord at any time during the Term of this
Lease, Landlord and Tenant agree to enter into a separate agreement more fully
delineating the rights and obligations of Landlord and Tenant herein granted
with respect to the Roof Installation.

         7.05. Landlord shall cause to be installed, at Landlord's expense, two
(2) four-inch conduits containing fiber optics cabling to a location in the
Building to be identified by Landlord. Landlord shall provide Tenant access to
riser space in a location designated by Landlord within a telephone or
mechanical room of the Building, to enable Tenant to install two (2) four-inch
diverse conduits from the conduit lines servicing the Building to the Premises,
which installation shall be at Tenant's expense.


                                   ARTICLE 8

                           ASSIGNMENT AND SUBLETTING

         8.01. Neither Tenant nor its legal representatives or successors in
interest shall, by operation of law or otherwise, assign, mortgage, pledge,
encumber or otherwise transfer this Lease or any part hereof, or the interest of
Tenant under this Lease, or in any sublease or the rent thereunder. The Premises
or any part thereof shall not be sublet, occupied or used for any purpose by
anyone other than Tenant, without Tenant's obtaining in each instance the prior
written consent of Landlord in the manner hereinafter provided. Tenant shall not
modify, extend, or amend a sublease previously consented to by Landlord without
obtaining Landlord's prior written consent thereto. Provided that no Event of
Default has occurred and is outstanding, Landlord agrees not to unreasonably
withhold its consent to any request by Tenant to assign this Lease or to
sublease the Premises, provided that Landlord may consider any reasonable factor
in determining whether to grant its consent to any such request to assign or
sublease. Landlord and Tenant specifically agree, without limitation, that
Landlord may reasonably refuse to consent to an assignment or subletting if the
proposed assignee or subtenant is (i) not financially capable of satisfying its
obligations under this Lease or its sublease, as the case may be, (ii) either a
governmental authority or agency, an organization or person enjoying sovereign
or diplomatic immunity, a medical or dental practice or other user which will
attract a volume, frequency or type of visitor or employee to the Building which
is not consistent with the standards of a high quality office building or which
will impose an excessive demand on or use of the facilities or services of the
Building, or (iii) not in keeping with the tenant mix of the Building or not of
the type of tenant which Landlord would reasonably consider as a tenant in the
Building.

         8.02. An assignment of this Lease shall be deemed to have occurred (a)
if in a single transaction or in a series of transactions more than 50% in
interest in Tenant, any guarantor of this Lease, or any subtenant (whether
stock, partnership, interest or otherwise) is transferred, diluted, reduced, or
otherwise affected with the result that the present holder or owners of Tenant,
such guarantor, or such subtenant have less than a 50% interest in Tenant, such
guarantor or such subtenant, or (b) if Tenant's obligations under this Lease are
taken over or assumed in consideration of Tenant leasing space in another office
building. The transfer of the outstanding capital stock of any corporate Tenant,
guarantor or subtenant through the "over-the-counter" market or any recognized
national securities exchange (other than by persons owning 5% or more of the
voting calculation of such 50% interest of clause 8.02(a) above) shall not be
included in the calculation of such 50% interest in clause(a) above.

                                       7
<PAGE>

          8.03.  Notwithstanding anything to the contrary in Section 8.01,
Tenant shall have the right, upon ten (10) days' prior written notice to
Landlord, to (a) sublet all or part of the Premises to any related corporation
or other entity which controls Tenant, is controlled by Tenant or is under
common control with Tenant; or (b) assign this Lease to a successor corporation
into which or with which Tenant is merged or consolidated or which acquired
substantially all of Tenant's assets and property; provided that (i) such
successor corporation assumes substantially all of the obligations and
liabilities of Tenant and shall have assets, capitalization and net worth at
least equal to the assets, capitalization and net worth of Tenant as of the date
of this Lease as determined by generally accepted accounting principles, and
(ii) Tenant shall provide in its notice to Landlord the information required in
Section 8.04. For the purpose hereof "control" shall mean ownership of not less
than 50% of all the voting stock or legal and equitable interest in such
corporation or entity.

          8.04.  If Tenant should desire to assign this Lease or sublet the
Premises (or any part thereof), Tenant shall give Landlord written notice no
later than thirty (30) days in advance of the proposed effective date of any
other proposed assignment or sublease, specifying (a) the name, current address,
and business of the proposed assignee or sublessee, (b) the amount and location
of the space within the Premises proposed to be so subleased, (c) the proposed
effective date and duration of the assignment or subletting, (d) the proposed
rent or consideration to be paid to Tenant by such assignee or sublessee, and
(e) financial statements and other information as Landlord may reasonably
request to evaluate the proposed assignment or sublease. For assignments and
sublettings other than those permitted by Section 8.03, Landlord shall have
fifteen (15) days following receipt of such notice and other information
requested by Landlord within which to notify Tenant in writing that Landlord
elects: (i) to terminate this Lease as to the space so affected as of the
proposed effective date set forth in Tenant's notice, in which event Tenant
shall be relieved of all further obligations hereunder as to such space, except
for obligations under Articles 17 and 22 and all other provisions of this Lease
which expressly survive the termination hereof; or (ii) to permit Tenant to
assign or sublet such space; provided, however, that, if the rent rate agreed
upon between Tenant and its proposed subtenant is greater than the rent rate
that Tenant must pay Landlord hereunder for that portion of the Premises, or if
any consideration shall be promised to or received by Tenant in connection with
such proposed assignment or sublease (in addition to rent), then fifty percent
(50%) of such excess rent and other consideration shall be considered Additional
Rent owed by Tenant to Landlord (less brokerage commissions, tenant improvement
costs, design fees, attorneys' fees and other disbursements reasonably incurred
by Tenant in connection with such assignment and subletting); or (iii) to refuse
to consent to Tenant's assignment or subleasing of such space and to continue
this Lease in full force and effect; provided, so long as no Event of Default
has occurred and is outstanding, Landlord agrees not to unreasonably withhold
its consent to a proposed assignment or subletting taking into consideration the
factors described in Section 8.01 above. Tenant agrees to reimburse Landlord for
legal fees and any other reasonable costs incurred by Landlord in connection
with any permitted assignment or subletting. Tenant shall deliver to Landlord
copies of all documents executed in connection with any permitted assignment or
subletting, which documents shall be in form and substance reasonably
satisfactory to Landlord and which shall require any assignee to assume
performance of all terms of this Lease to be performed by Tenant or any
subtenant to comply with all the terms of this Lease to be performed by Tenant.
No acceptance by Landlord of any Rent or any other sum of money from any
assignee, sublessee or other category of transferee shall be deemed to
constitute Landlord's consent to any assignment, sublease, or transfer. Tenant
shall not be allowed to subdivide the Premises in connection with any permitted
subletting without Landlord's consent.

          8.05.  Any attempted assignment or sublease by Tenant in violation of
the terms and provisions of this Article 8 shall be void and shall constitute a
material breach of this Lease. In no event, shall any assignment, subletting or
transfer, whether or not with Landlord's consent, relieve Tenant of its primary
liability under this Lease for the entire Term, and Tenant shall in no way be
released from the full and complete performance of all the terms hereof. If
Landlord takes possession of the Premises before the expiration of the Term of
this Lease, Landlord shall have the right, at its option, to terminate all
subleases, or to take over any sublease of the Premises or any portion thereof
and such subtenant shall attorn to Landlord, as its landlord, under all the
terms and obligations of such sublease occurring from and after such date, but
excluding previous acts, omissions, negligence or defaults of Tenant and any
repair or obligation in excess of available net insurance proceeds or
condemnation award.

          8.06.  The term "Landlord," as used in this Lease, so far as covenants
or obligations on the part of Landlord are concerned, shall be limited to mean
and include only the owner or owners, at the time in question, of the fee title
to, or a lessee's interest in a ground lease of, the Land or the Building. In
the event of any transfer, assignment or other conveyance or transfers of any
such title or interest, Landlord herein named, and in case of any subsequent
transfers, the then grantor shall be automatically freed and relieved from and
after the date of such transfer, assignment or conveyance of all liability as
respects the performance of any covenants or obligations on the part of Landlord
contained in this Lease thereafter to be performed and, without further
agreement, the transferee of such title or interest shall be deemed to have
assumed and agreed to observe and perform any and all obligations of Landlord
hereunder, during its ownership of the Project. Landlord may transfer its
interest in the Project without the consent of Tenant and such transfer or
subsequent transfer shall not be deemed a violation on Landlord's part of any of
the terms of this Lease.

                                   ARTICLE 9

                                    REPAIRS

          9.01.  Except for ordinary wear and tear and except as otherwise
provided in Section 9.02, Landlord shall perform all maintenance and make all
repairs and replacements to the Premises (including the Leasehold Improvements).
Tenant shall pay to Landlord the actual cost (including a fee equal to fifteen
percent (15%) of actual costs to cover a fee for Landlord's agent or manager)
for (a) all maintenance, repairs and replacements within the Premises (including
the Leasehold Improvements), other than maintenance, repairs and replacements to
any Building system or component within the Building core serving the tenants in
the Building ("Central Systems")

                                       8
<PAGE>

located within the Premises; or (b) all repairs and replacements necessitated by
damage to the Project (including the Building structure and the Central Systems)
caused by the negligence or willful misconduct of Tenant or its agents,
contractors, invitees and licensees. Amounts payable by Tenant pursuant to this
Section 9.01 shall be payable on demand after receipt of an invoice therefor
from Landlord. Landlord has no obligation and has made no promise to maintain,
alter, remodel, improve, repair, decorate, or paint the Premises or any part
thereof, except as specifically set forth in this Lease. In no event shall
Landlord have any obligation to maintain, repair or replace any furniture,
furnishings, fixtures or personal property of Tenant.

          9.02.  Tenant shall keep the Premises (including the Leasehold
Improvements) in good order and in a safe, neat and clean condition. No
representations respecting the condition of the Premises or the Building or the
other portions of the Project have been made by Landlord to Tenant except as
specifically set forth in this Lease. Except as provided in Section 10.01 or
specifically consented to by Landlord, Tenant shall not perform any maintenance
or repair work or make any replacement in or to the Premises (including the
Leasehold Improvements), and any branch of a Central System serving the Premises
("Branch System"), but rather shall promptly notify Landlord of the need for
such maintenance, repair or replacement so that Landlord may proceed to perform
the same. In the event Landlord specifically consents to the performance of any
maintenance or the making of any repairs or replacements by Tenant and Tenant
fails to promptly commence and diligently pursue the performance of such
maintenance or the making of such repairs or replacements, then Landlord, at its
option, may perform such maintenance or make such repairs and Tenant shall
reimburse Landlord, on demand after Tenant receives an invoice therefor, the
cost thereof plus fifteen percent (15%) of the actual costs to cover a fee for
Landlord's agent or manager.

          9.03.  All repairs made by Tenant pursuant to Section 9.02 shall be
performed in a good and workmanlike manner by contractors or other repair
personnel selected by Tenant and approved by Landlord; provided, however, that
neither Tenant nor its contractors or repair personnel shall be permitted to do
any work affecting the Central Systems of the Building.

          9.04.  Subject to the other provisions of this Lease imposing
obligations regarding repair upon Tenant, Landlord shall repair all machinery
and equipment necessary to provide the services of Landlord described in Article
7 and for repair of all portions of the Project which do not comprise a part of
the Premises and are not leased to others.

                                  ARTICLE 10

                                  ALTERATIONS

          10.01. Tenant shall not at any time during the Term make any
alterations to the Premises without first obtaining Landlord's written consent
thereto, which consent Landlord shall not unreasonably withhold or delay but
which consent may be conditioned upon Tenant's agreement to remove the
alterations at the end of the Term; provided, however, Tenant may make, upon the
delivery of notice to Landlord (but without the consent of Landlord), cosmetic
non-structural changes to the Premises costing less than $5,000.00 that do not
affect the Central Systems of the Building or the structural integrity of the
Building, so long as Tenant otherwise complies with the provisions of this
Article 10. Should Tenant desire to make any alterations to the Premises, Tenant
shall submit all plans and specifications for such proposed alterations to
Landlord for Landlord's review and approval before Tenant allows any such work
to commence. Tenant shall select and use only contractors approved by Landlord.
Upon Tenant's receipt of written approval from Landlord and upon Tenant's
payment of any third party review costs reasonably incurred by Landlord, Tenant
shall have the right to proceed with the construction of all approved
alterations, in strict compliance with the approved plans and specifications.
All alterations shall be made at Tenant's sole cost and expense, either by
Tenant's contractors or, at Tenant's option, by Landlord's contractor on terms
reasonably satisfactory to Tenant, including a fee of ten percent (10%) of the
actual costs of such work to cover a fee for Landlord's agent or manager in
supervising and coordinating such work. In no event, however, shall anyone other
than Landlord or Landlord's employees or representatives perform work to be done
which affects the Central Systems of the Building.

          10.02. All construction, alterations and repair work done by or for
Tenant shall (a) be performed in such a manner as to maintain harmonious labor
relations; (b) not adversely affect the safety of the Project, the Building or
the Premises or the systems thereof and not affect the Central systems of the
Building; (c) comply with all building, safety, fire, plumbing, electrical, and
other codes and governmental and insurance requirements; (d) not result in any
usage in excess of Building Standard of water, electricity, gas, or other
utilities or of heating, ventilating or air-conditioning (either during or after
such work); (e) be completed promptly and in a good and workmanlike manner and
in compliance with, and subject to, all of the provisions of the Lease; and (f)
not disturb Landlord or other tenants in the Building. After completion of any
alterations to the Premises, Tenant will deliver to Landlord a copy of "as
built" plans and specifications depicting and describing such alterations.

          10.03. All leasehold improvements, alterations and other physical
additions made to or installed by or for Tenant in the Premises shall be and
remain Landlord's property (except for Tenant's furniture, personal property and
movable trade fixtures). Tenant agrees to remove, at its sole cost and expense,
all of Tenant's furniture, personal property and movable trade fixtures from the
Premises, on or before the Expiration Date or any earlier date of termination of
this Lease. Tenant shall repair, or promptly reimburse Landlord for the cost of
repairing, all damage done to the Premises or the Building by such removal. If
Tenant fails to remove any of Tenant's furniture, personal property or movable
trade fixtures by the Expiration Date or any sooner date of termination of the
Lease or, if Tenant fails to remove any leasehold improvements, alterations and
other physical additions made by Tenant to the Premises which Landlord advised
Tenant at the time of installation were to be removed at the end of the Term,
Landlord shall have the right, on the fifth (5th) day after Landlord's delivery
of written notice to Tenant, to deem

                                       9
<PAGE>

such property abandoned by Tenant and to remove, store, sell, discard or
otherwise deal with or dispose of such abandoned property in a commercially
reasonable manner. Tenant shall be liable for all costs of such disposition of
Tenant's abandoned property, and Landlord shall have no liability to Tenant in
any respect regarding such property of Tenant. The provisions of this Section
10.03 shall survive the expiration or any earlier termination of this Lease.


                                  ARTICLE 11

                                     LIENS

          11.01. Tenant shall keep the Project, the Building and the Premises
and Landlord's interest therein from any liens arising from any work performed,
materials furnished, or obligations incurred by, or on behalf of Tenant. Notice
is hereby given that neither Landlord nor any mortgagee or lessor of Landlord
shall be liable for any labor or materials furnished to Tenant, except as
furnished to Tenant by Landlord pursuant to Exhibit C. If any lien is filed for
                                            ---------
such work or materials, such lien shall encumber only Tenant's interest in
leasehold improvements on the Premises. Within thirty (30) days after Tenant
learns of the filing of any such lien, Tenant shall either discharge and cancel
such lien of record or post a bond sufficient under the laws of the State of
Texas to cover the amount of the lien claim plus any penalties, interest,
attorneys' fees, court costs, and other legal expenses in connection with such
lien. If Tenant fails to so discharge or bond such lien within thirty (30)
calendar days after written demand from Landlord, Landlord shall have the right,
at Landlord's option, to pay the full amount of such lien without inquiry into
the validity thereof, and Landlord shall be promptly reimbursed by Tenant, as
Additional Rent, for all amounts so paid by Landlord, including expenses,
interest, and attorneys' fees.

                                  ARTICLE 12

                         USE AND COMPLIANCE WITH LAWS

          12.01. The Premises shall be used only for executive and
administrative offices for the conduct of Tenant's business and for general
office use, and is expressly limited to the uses specifically set forth in
Section 1.01Q and for no other purposes whatsoever. Tenant shall use and
maintain the Premises in a clean, careful, safe, lawful and proper manner and
shall not allow within the Premises, any offensive noise, odor, conduct or
private or public nuisance or permit Tenant's employees, agents, licensees or
invitees to create a public or private nuisance or act in a disorderly manner
within the Building or in the Project. Landlord represents that any certificate
of occupancy issued with respect to the Premises shall allow use for executive
and administrative offices.

          12.02. Tenant shall, at Tenant's sole expense, (a) comply with all
laws, orders, ordinances, and regulations of federal, state, county, and
municipal authorities having jurisdiction over the Premises, (b) comply with any
directive, order or citation made pursuant to law by any public officer
requiring abatement of any nuisance or which imposes upon Landlord or Tenant any
duty or obligation arising from Tenant's occupancy or use of the Premises or
from conditions which have been created by or at the request or insistence of
Tenant, or required by reason of a breach of any of Tenant's obligations
hereunder or by or through other fault of Tenant, (c) comply with all insurance
requirements applicable to the Premises and (d) indemnify and hold Landlord
harmless from any loss, cost, claim or expense which Landlord incurs or suffers
by reason of Tenant's failure to comply with its obligations under clauses (a),
(b) or (c) above. If Tenant receives notice of any such directive, order
citation or of any violation of any law, order, ordinance, regulation or any
insurance requirement, Tenant shall promptly notify Landlord in writing of such
alleged violation and furnish Landlord with a copy of such notice.

                                  ARTICLE 13

                             DEFAULT AND REMEDIES

          13.01. The occurrence of any one or more of the following events shall
constitute an Event of Default (herein so called) of Tenant under this Lease:
(a) if Tenant fails to pay any Rent hereunder as and when such Rent becomes due
and such failure shall continue for more than five (5) days after Landlord gives
Tenant written notice of past due Rent; (b) if Tenant fails to pay Rent on time
more than twice in any period of twelve (12) months; (c) if the Premises become
vacant, deserted, or abandoned for more than thirty (30) consecutive days and
Tenant fails to pay timely Rent or any other sum due under this Lease; (d) if
Tenant dissolves its business; (e) if any petition is filed by or against Tenant
or any guarantor of this Lease under any present or future section or chapter of
the Bankruptcy Code, or under any similar law or statute of the United States or
any state thereof (which, in the case of an involuntary proceeding, is not
permanently discharged, dismissed, stayed, or vacated, as the case may be,
within sixty (60) days of commencement), or if any order for relief shall be
entered against Tenant or any guarantor of this Lease in any such proceedings;
(f) if Tenant or any guarantor of this Lease becomes insolvent or makes a
transfer in fraud of creditors or makes an assignment for the benefit of
creditors; (g) if a receiver, custodian, or trustee is appointed for the
Premises or for all or substantially all of the assets of Tenant or of any
guarantor of this Lease, which appointment is not vacated within sixty (60) days
following the date of such appointment; or (h) if Tenant fails to perform or
observe any other terms of this Lease and such failure shall continue for more
than thirty (30) days after Landlord gives Tenant notice of such failure, or, if
such failure cannot be corrected within such thirty (30) day period, if Tenant
does not commence to correct such default within said thirty (30) day period and
thereafter diligently prosecute the correction of same to completion within a
reasonable time.

          13.02. Upon the occurrence of any Event of Default, Landlord shall
have the right, at Landlord's option, to elect to do any one or more of the
following without further notice or demand to Tenant:

                 (a)  terminate this Lease, in which event Tenant shall
immediately surrender the Premises to Landlord, and, if Tenant fails to so
surrender, Landlord shall have the right to enter upon and take possession of
the

                                      10
<PAGE>

Premises and to expel or remove Tenant and its effects without being liable for
prosecution or any claim for damages therefor; and Tenant shall, and hereby
agrees to, indemnify Landlord for all loss and damage which Landlord suffers by
reason of such termination, including damages in an amount equal to the total of
(1) the costs of recovering the Premises and all other expenses incurred by
Landlord in connection with Tenant's default; (2) the unpaid Rent earned as of
the date of termination, plus interest at the Interest Rate; (3) the total Rent
which Landlord would have received under this Lease for the remainder of the
Term, but discounted to the then present value at a rate of eight percent (8%)
per annum, minus the fair market rental value for the balance of the Term,
determined as of the time of such default, discounted to the then present value
at a rate of eight percent (8%) per annum; and (4) all other sums of money and
damages owing by Tenant to Landlord; or

               (b)  enter upon and take possession of the Premises without
terminating this Lease and without being liable to prosecution or any claim for
damages therefor, and, if Landlord elects, relet the Premises on such terms as
Landlord deems advisable, in which event Tenant shall pay to Landlord on demand
the cost of repossession, renovating, repairing and altering the Premises for a
new tenant or tenants and any deficiency between the Rent payable hereunder and
the rent paid under such reletting; provided, however, that Tenant shall not be
entitled to any excess payments received by Landlord from such reletting.
Landlord's failure to relet the Premises shall not release or affect Tenant's
liability for Rent or for damages; or

               (c)  enter the Premises without terminating this Lease and
without being liable for prosecution or any claim for damages therefor and
maintain the Premises and repair or replace any damage thereto or do anything
for which Tenant is responsible hereunder. Tenant shall reimburse Landlord
immediately upon demand for any expenses which Landlord incurs in thus effecting
Tenant's compliance under this Lease, and Landlord shall not be liable to Tenant
for any damages with respect thereto.

        13.03. No agreement to accept a surrender of the Premises and no act or
omission by Landlord or Landlord's agents during the Term shall constitute an
acceptance or surrender of the Premises unless made in writing and signed by
Landlord. No re-entry or taking possession of the Premises by Landlord shall
constitute an election by Landlord to terminate this Lease unless a written
notice of such intention is given to Tenant. No provision of this Lease shall be
construed as an obligation upon Landlord to mitigate Landlord's damages under
the Lease.

        13.04. No provision of this Lease shall be deemed to have been waived by
Landlord unless such waiver is in writing and signed by Landlord. Landlord's
acceptance of Rent following an Event of Default hereunder shall not be
construed as a waiver of such Event of Default. No custom or practice which may
grow up between the parties in connection with the terms of this Lease shall be
construed to waive or lessen Landlord's right to insist upon strict performance
of the terms of this Lease, without a written notice thereof to Tenant from
Landlord.

        13.05. The rights granted to Landlord in this Article 13 shall be
cumulative of every other right or remedy provided in this Lease or which
Landlord may otherwise have at law or in equity or by statute, and the exercise
of one or more rights or remedies shall not prejudice or impair the concurrent
or subsequent exercise of other rights or remedies or constitute a forfeiture or
waiver of Rent or damages accruing to Landlord by reason of any Event of Default
under this Lease.

                                  ARTICLE 14

                                   INSURANCE

        14.01. A. Tenant, at its sole expense, shall obtain and keep in force
during the Term the following insurance: (a) "All Risk" insurance insuring all
property located in the Premises, including furniture, equipment, fittings,
installations, fixtures, supplies and any other personal property ("Tenant's
Property"), in an amount equal to the full replacement value; (b) Comprehensive
general public liability insurance including personal injury, bodily injury,
broad form property damage, operations hazard, owner's protective coverage,
contractual liability, with a cross liability clause and a severability of
interests clause to cover Tenant's indemnities set forth herein, and products
and completed operations liability, in limits not less than $1,000,000.00
inclusive per occurrence; (c) Worker's Compensation and Employer's Liability
insurance, with a waiver of subrogation endorsement, in form and amount as
required by applicable law; and (d) In the event Tenant performs any repairs or
alterations in the Premises, Builder's Risk insurance on an "All Risk" basis
(including collapse) on a completed value (non-reporting) form for full
replacement value covering all work incorporated in the Building and all
materials and equipment in or about the Premises; and (e) Improvements and
betterments.

        B.     Tenant shall have the right to include the insurance required by
Section 14.01A under Tenant's policies of "blanket insurance". All certificates
of insurance evidencing such coverage shall name Tenant as named insured
thereunder and shall name Landlord and all mortgagees and lessors of Landlord of
which Tenant has been notified, additional insureds, all as their respective
interest may appear. All such certificates shall be issued by insurers
acceptable to Landlord and in form satisfactory to Landlord. Tenant shall
deliver to Landlord certificates by the Commencement Date and, with respect to
renewals of such policies, not later than fifteen (15) days prior to the end of
the expiring term of coverage. All policies of insurance shall be primary and
non-contributing. All such policies and certificates shall contain an agreement
by the insurers to notify Landlord and any mortgagee or lessor of Landlord in
writing, by Registered U.S. mail, return receipt requested, not less than thirty
(30) days before any material change, reduction in coverage, cancellation,
including cancellation for nonpayment of premium.

        14.02. Landlord shall insure the Building against damage with casualty
and comprehensive general public liability insurance, all in such amounts and
with such deductible as Landlord reasonably deems appropriate. Notwithstanding
any contribution by Tenant to the cost of insurance premiums, as provided
hereinabove, Landlord

                                      11
<PAGE>

shall not be required to carry insurance of any kind on Tenant's Property, and
Tenant hereby agrees that Tenant shall have no right to receive any proceeds
from any insurance policies carried by Landlord.

          14.03. Tenant shall not knowingly conduct or permit to be conducted in
the Premises any activity, or place any equipment in or about the Premises or
the Building, which will invalidate the insurance coverage in effect or increase
the rate of fire insurance or other insurance on the Premises or the Building,
and Tenant shall comply with all requirements and regulations of Landlord's
casualty and liability insurer. In no event shall Tenant introduce or permit to
be kept on the Premises or brought into the Building any dangerous, noxious,
radioactive or explosive substance.

          14.04. Landlord and Tenant each hereby waive any right of subrogation
and right of recovery or cause of action for injury or loss to the extent that
such injury or loss is covered by fire, extended coverage, "All Risk" or similar
policies covering real property or personal property (or which would have been
covered if Tenant or Landlord, as the case may be, was carrying the insurance
required by this Lease). Said waivers shall be in addition to, and not in
limitation or derogation or, any other waiver or release contained in this
Lease.

                                  ARTICLE 15

                         DAMAGE BY FIRE OR OTHER CAUSE

          15.01. If the Building or any portion thereof is damaged or destroyed
by any casualty to the extent that, in Landlord's reasonable judgment, (a)
repair of such damage or destruction would not be economically feasible, or (b)
the damage or destruction to the Building cannot be repaired within three
hundred sixty (360) days after the date of such damage or destruction, or if the
proceeds from Landlord's insurance remaining after any required payment to any
mortgagee or lessor of Landlord are insufficient to repair such damage or
destruction, Landlord shall have the right, at Landlord's option, to terminate
this Lease by giving Tenant notice of such termination, within sixty (60) days
after the date of such damage or destruction.

          15.02. If the Premises or any portion thereof is damaged or destroyed
by any casualty, and if, in Landlord's reasonable opinion, the Premises cannot
be rebuilt or made fit for Tenant's purposes within one hundred eighty days
(180) after the date of such damage or destruction, or if the proceeds from
Landlord's insurance remaining after any required payment to any mortgagee or
lessor of Landlord are insufficient to repair such damage or destruction, then
either Landlord or Tenant shall have the right, at the option of either party,
to terminate this Lease by giving the other written notice, within sixty (60)
days after such damage or destruction.

          15.03. In the event of partial destruction or damage to the Building
or the Premises which is not subject to Section 15.01 or 15.02, but which
renders the Premises partially but not wholly untenantable, this Lease shall not
terminate and Rent shall be abated in proportion to the area of the Premises
which, in Landlord's reasonable opinion, cannot be used or occupied by Tenant as
a result of such casualty. Landlord shall in such event, within a reasonable
time after the date of such destruction or damage, subject to force majeure (as
defined in Section 25.06) or to Tenant Delay and to the extent and availability
of insurance proceeds, restore the Premises to as near the same condition as
existed prior to such partial damage or destruction. In no event shall Rent
abate or shall any termination occur if damage to or destruction of the Premises
is the result of the negligence or willful misconduct of Tenant, or Tenant's
agents, employees, representatives, contractors, successors, assigns, licensees
or invitees.

          15.04. If the Building or the Premises or any portion thereof is
destroyed by fire or other causes at any time during the last year of the Term,
then either Landlord or Tenant shall have the right, at the option of either
party, to terminate this Lease by giving written notice to the other within
sixty (60) days after the date of such destruction.

          15.05. Landlord shall have no liability to Tenant for inconvenience,
loss of business, or annoyance arising from any repair of any portion of the
Premises or the Building, unless such damage is caused solely by Landlord's
gross negligence. If Landlord is required by this Lease or by any mortgagee or
lessor of Landlord to repair, or if Landlord undertakes to repair, Landlord
shall use reasonable efforts to have such repairs made promptly and in a manner
which will not unnecessarily interfere with Tenant's occupancy.

          15.06. In the event of termination of this Lease pursuant to Sections
15.01, 15.02, or 15.04, then all Rent shall be apportioned and paid to the date
on which possession is relinquished or the date of such damage, whichever last
occurs, and Tenant shall immediately vacate the Premises according to such
notice of termination; provided, however, that those provisions of this Lease
which are designated to cover matters of termination and the period thereafter
shall survive the termination hereof.

                                  ARTICLE 16

                                 CONDEMNATION

          16.01. In the event any portion of the Building, the Premises or the
Project are taken or condemned by eminent domain or by any conveyance in lieu
thereof (such taking, condemnation or conveyance in lieu thereof being
hereinafter referred to as "condemnation"), which taking, in Landlord's
judgment, is such that the Building or the Premises cannot be restored in an
economically feasible manner for use substantially as originally designed, then
Landlord shall have the right, at Landlord's option, to terminate this Lease,
effective as of the date specified by Landlord in a written notice of
termination from Landlord to Tenant and Rent shall be apportioned as of the date
of such termination.

                                      12
<PAGE>

          16.02. In the event any portion of the Parking Facilities shall be
taken by condemnation, which taking in Landlord's judgment is such that the
Parking Facilities cannot be restored in an economically feasible manner for use
substantially as originally designed, including in such consideration the
possible use of additional parking facilities in the vicinity of the Building,
then Landlord shall have the right, at Landlord's option, to terminate this
Lease, effective as of the date specified by Landlord in a written notice of
termination from Landlord to Tenant.

          16.03. In the event that a portion of the Premises shall be taken by
condemnation, and this Lease is not terminated pursuant to Section 16.01, then
this Lease shall be terminated as of the date of such condemnation as to the
portion of the Premises so taken, and this Lease shall remain in full force and
effect as to the remainder of the Premises.

          16.04. All compensation awarded or paid upon a condemnation of any
portion of the Project shall belong to and be the property of Landlord without
participation by Tenant. Nothing herein shall be construed, however, to preclude
Tenant from prosecuting any claim directly against the condemning authority for
loss of business, loss of good will, moving expenses, damage to, and cost of
removal of, trade fixtures, furniture and other personal property belonging to
Tenant; provided, however, that Tenant shall make no claim which shall diminish
or adversely affect any award claimed or received by Landlord.

          16.05. If any portion of the Project other than the Building or the
Parking Facilities is taken by condemnation, or if the temporary use or
occupancy of all or any part of the Premises shall be taken by condemnation
during the Term, this Lease shall be and remain unaffected by such condemnation,
and Tenant shall continue to pay in full the Rent payable hereunder.

                                  ARTICLE 17

                                INDEMNIFICATION

          17.01. Except as expressly provided in Section 17.02 below, Tenant and
its agents employees, representatives, contractors, licensees and invitees,
hereby waive all claims against, and agree to indemnify and hold harmless,
Landlord for damage to any property or injury to, or death of, any agent,
employee, contractor, or invitee of Tenant in, upon, or about the Project,
including the Premises, arising at any time and from any cause other than solely
by reason of the gross negligence or willful misconduct of Landlord, its agents,
employees, representatives, or contractors. Without limiting the generality of
the foregoing, Landlord shall not be liable for any injury or damage to persons
or property resulting from the condition or design of, or any defective,
Building or its mechanical systems or equipment which may exist or occur or from
any fire, explosion, falling plaster, steam, gas, electricity, water, rain,
flood, snow, or leaks from any part of the Premises or from the pipes,
appliances, plumbing works, roof, or subsurface of any floor or ceiling, or from
the street or any other place, or by dampness or by any other similar cause
unless the same is caused solely by the gross negligence or willful misconduct
of Landlord, its agents, employees, representatives or contractors. Landlord
shall not be liable for any such damage caused by other tenants or persons in
the Building or by occupants of adjacent property thereto, or by the public, or
caused by construction (unless caused solely by the gross negligence or willful
misconduct of Landlord) or by any private, public or quasi-public work. Tenant,
for itself and its agents, employees, representatives, contractors, successors,
assigns, invitees and licensees, expressly assumes all risks of injury or damage
to person or property, within proximate or remote, resulting from the condition
of the Project or any part thereof. Tenant's foregoing indemnity shall include
attorneys' fees, investigation costs, and all other reasonable costs and
expenses incurred by Landlord in any connection therewith. The provisions of
this Article 17 shall survive the expiration or termination of this Lease with
respect to any damage, injury, or death occurring before such expiration or
termination.

          17.02. Landlord shall, and hereby agrees to, indemnify and hold Tenant
harmless from any damages in connection with loss of life, bodily or personal
injury or property damage arising from any occurrence in the Common Areas of the
Project when not solely the result of the gross negligence or willful misconduct
of Tenant, and its agents, employees, representatives, contractors, licensees,
and invitees.

                                  ARTICLE 18

                    SUBORDINATION AND ESTOPPEL CERTIFICATES

          18.01. This Lease and all rights of Tenant hereunder are subject and
subordinate to all underlying leases now or hereafter in existence, and to any
supplements, amendments, modifications, and extensions of such leases heretofore
or hereafter made and to any deeds to secure debt, mortgages, or other security
instruments which now or hereafter cover all or any portion of the Project or
any interest of Landlord therein, and to any advances made on the security
thereof, and to any increases, renewals, modifications, consolidations,
replacements, and extensions of any of such mortgages. This provision is
declared by Landlord and Tenant to be self-operative and no further instrument
shall be required to effect such subordination of this Lease. Upon demand,
Tenant shall execute, acknowledge, and deliver to Landlord any further
instruments and certificates evidencing such subordination as Landlord, and any
mortgagee or lessor of Landlord shall reasonably require; provided, Landlord
shall use reasonable efforts to cause its mortgagee to include in any such
subordination agreement non-disturbance provisions, reasonably satisfactory to
Tenant and such mortgagee, whereby Landlord's mortgagee shall agree to accept
attornment from Tenant under this Lease, in conformity with the terms hereof, in
the event a Successor Landlord (hereinafter defined) shall succeed to the
interests of Landlord hereunder. Tenant shall not unreasonably withhold, delay,
or defer its written consent reasonable modifications in this Lease which are a
condition of any financing for the Project or any reciprocal easement agreement
with facilities in the vicinity of the Building, provided that such
modifications do not increase the obligations of Tenant hereunder or materially
and adversely affect Tenant's use and enjoyment of the Premises.

                                      13
<PAGE>

          18.02. Notwithstanding the generality of the foregoing provisions of
Section 18.01, any mortgagee or lessor of Landlord shall have the right at any
time to subordinate any such mortgage or underlying lease to this Lease, or to
any of the provisions hereof, on such terms and subject to such conditions as
such mortgagee or lessor of Landlord may consider appropriate in its discretion.
At any time, before or after the institution of any proceedings for the
foreclosure of any such mortgage, or the sale of the Building under any such
mortgage, or the termination of any underlying lease, Tenant shall, upon request
of such mortgagee or any person or entities succeeding to the interest of such
mortgagee or the purchaser at any foreclosure sale ("Successor Landlord"),
automatically become the Tenant (or if the Premises has been validly subleased,
the subtenant) of the Successor Landlord, without change in the terms or other
provisions of this Lease (or, in the case of a permitted sublease, without
change in this Lease or in the instrument setting forth the terms of such
sublease); provided, however, that the Successor Landlord shall not be (i) bound
by any payment made by Tenant of Rent or Additional Rent for more than one (1)
month in advance, except for a Security Deposit previously paid to Landlord (and
then only if such Security Deposit has been deposited with and is under the
control of the Successor Landlord), (ii) bound by any termination, modification,
amendment or surrender of the Lease done without the Successor Landlord's
consent, (iii) liable for any damages or subject to any offset or defense by
Tenant to the payment of Rent by reason of any act or omission of any prior
landlord (including Landlord), or (iv) personally or corporately liable, in any
event, beyond the limitations on landlord liability set forth in Section 25.05
of this Lease. This agreement of Tenant to attorn to a Successor Landlord shall
survive any such foreclosure sale, trustee's sale conveyance in lieu thereof or
termination of any underlying lease. Tenant shall upon demand at any time,
before or after any such foreclosure or termination execute, acknowledge, and
deliver to the Successor Landlord any written instruments and certificates
evidencing such attornment as such Successor Landlord may reasonably require.

          18.03. Tenant shall, from time to time, within ten (10) days after
request from Landlord, or from any mortgagee or lessor of Landlord, execute,
acknowledge and deliver in recordable form a certificate certifying, to the
extent true, that this Lease, as the Lease may have been amended, is in full
force and effect; that the Term has commenced and the full amount of the Rent
then accruing hereunder; the dates to which the Rent has been paid; that Tenant
has accepted possession of the Premises and that any improvements required by
the terms of this Lease to be made by Landlord have been completed to the
satisfaction of Tenant; the amount, if any, that Tenant has paid to Landlord as
a Security Deposit; that no Rent under this Lease has been paid more than thirty
(30) days in advance of its due date; that the address for notices to be sent to
Tenant is as set forth in this Lease, or has been changed as set forth in the
certificate; that Tenant has no charge, lien, or claim of offset under this
Lease or otherwise against Rent or other charges due or to become due hereunder;
that, to the knowledge of Tenant, Landlord is not then in default under this
Lease; and such other matters as may be reasonably requested by Landlord or any
mortgagee or lessor of Landlord. Any such certificate may be relied upon by
Landlord, any Successor Landlord, or any mortgagee or lessor of Landlord.
Landlord agrees periodically to furnish, when reasonably requested in writing by
Tenant, certificates signed by Landlord containing information similar to the
foregoing information.

          18.04. No act or failure to act on the part of Landlord which would
entitle Tenant under the terms of this Lease, or by law, to be relieved of
Tenant's obligations hereunder or to terminate this Lease, shall result in a
release of such obligations or a termination of this Lease unless (a) Tenant has
given notice by registered or certified mail to any mortgagee or lessor of
Landlord whose address shall have been furnished to Tenant, and (b) Tenant
offers such mortgagee or lessor of Landlord a reasonable opportunity to cure the
default, including time to obtain possession of the Premises by power of sale or
judicial foreclosure, if such should prove necessary to effect a cure.

                                  ARTICLE 19

                           SURRENDER OF THE PREMISES

          19.01. By no later than 11:59 p.m. of the Expiration Date or the date
of earlier termination of this Lease, or upon any re-entry of the Premises by
Landlord without terminating this Lease pursuant to Section 13.02(b), Tenant, at
Tenant's sole cost and expense, shall peacefully vacate and surrender the
Premises to Landlord in good order, broom clean and in the same condition as at
the beginning of the Term or as the Premises may thereafter have been improved,
reasonable use and wear thereof and repairs which are Landlord's obligations
under Articles 9, 15 and 16 only excepted, and Tenant shall remove all of
Tenant's Property and turn over all keys for the Premises to Landlord.

          19.02. Should Tenant continue to hold the Premises after the
expiration or earlier termination of this Lease, such holding over, unless
otherwise agreed to by Landlord in writing, shall constitute and be construed as
a tenancy at sufferance at monthly installments of Rent equal to one hundred
fifty percent (150%) of the monthly portion of Base Rent in effect as of the
date of expiration or earlier termination, plus Tenant's Operating Costs
Payment, and subject to all of the other terms, charges and expenses set forth
herein except any right to renew this Lease or to expand the Premises or any
right to additional services. Tenant shall also be liable to Landlord for all
damage which Landlord suffers because of any holding over by Tenant, and Tenant
shall indemnify Landlord against all claims made by any other tenant or
prospective tenant against Landlord resulting from delay by Landlord in
delivering possession of the Premises to such other tenant or prospective
tenant. The provisions of this Article 19 shall survive the expiration or
earlier termination of this Lease.

                                  ARTICLE 20

                          LANDLORD'S RIGHT TO INSPECT

          20.01. Landlord shall retain duplicate keys to all doors of the
Premises. Tenant shall provide Landlord with new keys should Tenant receive
Landlord's consent to change the locks. Landlord shall have the right to enter
the Premises at reasonable hours upon prior reasonable notice (or, in the event
of an emergency, at any hour without

                                      14
<PAGE>

prior notice); provided, however, Landlord shall use reasonable efforts to
minimize interference with Tenant's business. Landlord shall not be liable to
Tenant for the exercise of Landlord's rights under this Article 20 and Tenant
hereby waives any claims for damages for any injury, inconvenience or
interference with Tenant's business, any loss of occupancy or quiet enjoyment of
the Premises, and any other loss occasioned thereby.

                                  ARTICLE 21

                               SECURITY DEPOSIT

          21.01. On or before the date Landlord delivers the Premises to Tenant
in Base Premises Condition, Tenant shall deliver to Landlord a $1,000,000.00
letter of credit (the "Security Deposit") that is issued by a national banking
association and is in form and substance reasonably satisfactory to Landlord.
Upon the occurrence of any Event of Default by Tenant, Landlord shall have the
right, without prejudice to any other remedy, to submit a sight draft to the
bank which issued the letter of credit representing the Security Deposit, in an
amount equal to a sum necessary to pay any arrearages in Rent, and any other
damage, injury or expense. So long as no Event of Default has occurred during
the first year of the Term, then the Security Deposit may be reduced to a
$500,000.00 letter of credit, which replacement letter of credit shall be issued
by a national banking association and shall be in form and substance reasonably
satisfactory to Landlord. So long as no Event of Default has occurred during the
first two (2) years of the Term, then Landlord shall return the Security Deposit
to Tenant on the second (2/nd/) anniversary of the Commencement Date. If
Landlord transfers its interest in the Premises during the Term, Landlord shall
assign the Security Deposit to the transferee (and Tenant shall execute such
documents as may be necessary to effect such transfer), and thereafter Landlord
shall have no further liability to Tenant for the Security Deposit. Tenant shall
pay all fees charged by the bank issuing the letter of credit representing the
Security Deposit, and so long as no Event of Default has occurred during the
first two (2) years of the Term, then Tenant shall be entitled to an abatement
of the portion of Base Rent next becoming due under this Lease after the second
(/2nd/) anniversary date in an amount equal to the lesser of (a) the fees paid
by Tenant for the issuance of the letter of credit representing the Security
Deposit, or (b) $11,250.00.

                                  ARTICLE 22

                                   BROKERAGE

          22.01. Tenant and Landlord each represent and warrant to the other
that it has not entered into any agreement with, or otherwise had any dealings
with, any broker or agent in connection with the negotiation or execution of
this Lease which could form the basis of any claim by any such broker or agent
for a brokerage fee or commission, finder's fee, or any other compensation of
any kind or nature in connection herewith, other than with Broker, and each
party shall, and hereby agrees to, indemnify and hold the other harmless from
all costs (including court costs, investigation costs, and attorneys' fees),
expenses, or liability for commissions or other compensation claimed by any
broker or agent with respect to this Lease which arise out of any agreement or
dealings, or alleged agreement or dealings, between the indemnifying party and
any such agent or broker, other than with Broker. This provision shall survive
the expiration or earlier termination of this Lease.

                                  ARTICLE 23

                      OBSERVANCE OF RULES AND REGULATIONS

          23.01. Tenant and Tenant's servants, employees, agents, visitors, and
licensees shall observe faithfully and comply strictly with all Rules and
Regulations (herein so called) attached to this Lease as such Rules and
Regulations may be changed from time to time. Landlord shall at all times have
the right to make reasonable changes in and additions to such Rules and
Regulations; provided Landlord gives Tenant prior notice of such changes and
provided that such new rules and regulations or changes in existing rules and
regulations do not conflict with this Lease, and do not materially interfere
with the lawful conduct of Tenant's business in the Premises. Landlord shall not
be liable to Tenant for the failure or refusal by any other tenant, guest,
invitee, visitor, or occupant of the Building to comply with any of the Rules
and Regulations.

                                  ARTICLE 24

                                    NOTICES

          24.01. All notices, consents, demands, requests, documents, or other
communications (other than payment of Rent) required or permitted hereunder
(collectively, "notices") shall be deemed given, whether actually received or
not, when dispatched for hand delivery or delivery by air express courier (with
signed receipts) to the other party, or on the second Business Day after deposit
in the United States mail, postage prepaid, certified, return receipt requested,
except for notice of change of address which shall be deemed given only upon
actual receipt, or on the same Business Day if sent by telecopier prior to 5:00
p.m., local Austin, Texas time, and the sending telecopier generates a written
confirmation of sending and the providing party follows up with a hard copy of
such notice being sent the same Business Day by another approved method for
notice as provided in this Section 24.01. The addresses of the parties for
notices are set forth in Article 1, or any such other addresses subsequently
specified by each party in notices given pursuant to this Section 24.01.

                                      15
<PAGE>

                                  ARTICLE 25

                                 MISCELLANEOUS

          25.01. Professional Fees. In any action or proceeding brought by
                 -----------------
either party against the other under this Lease, the prevailing party shall be
entitled to recover from the other party its professional fees for attorneys,
appraisers and accountants, its investigation costs, and any other legal
expenses and court costs incurred by the prevailing party in such action or
proceeding.

          25.02. Reimbursements. Wherever the Lease requires Tenant to reimburse
                 --------------
Landlord for the cost of any item, such costs will be the reasonable and
customary charge periodically established by Landlord for such item, including a
fee for Landlord's manager's supervision in connection with providing such item.

          25.03. Severability. Every agreement contained in this Lease is, and
                 ------------
shall be construed as, a separate and independent agreement. If any term of this
Lease or the application thereof to any person or circumstances shall be invalid
or unenforceable, the remaining agreements contained in this Lease shall not be
affected.

          25.04. Non-Merger. There shall be no merger of this Lease with any
                 ----------
ground leasehold interest or the fee estate in the Project or any part thereof
by reason of the fact that the same person may acquire or hold, directly or
indirectly, this Lease or any interest in this Lease as well as any ground
leasehold interest or fee estate in the Project or any interest in such fee
estate.

          25.05. Landlord's Liability. Anything contained in this Lease to the
                 --------------------
contrary notwithstanding, Tenant agrees that Tenant shall look solely to the
estate and property of Landlord in the Project for the collection of any
judgment or other judicial process requiring the payment of money by Landlord
for any default or breach by Landlord under this Lease, subject, however, to the
prior rights of any mortgagee or lessor of the Project. No other assets of
Landlord or any partners, shareholders, or other principals of Landlord shall be
subject to levy, execution or other judicial process for the satisfaction of
Tenant's claim.

          25.06. Force Majeure. Whenever the period of time is herein prescribed
                 -------------
for action to be taken by Landlord or Tenant, Landlord or Tenant shall not be
liable or responsible for, and there shall be excluded from the computation for
any such period of time, any delays due to force majeure, which term shall
include strikes, riots, acts of God, shortages of labor or materials, war,
governmental approvals, laws, regulations, or restrictions, or any other cause
of any kind whatsoever which is beyond the reasonable control of Landlord or
Tenant. Force Majeure shall not excuse or delay Tenant's obligation to Rent or
any other amount due under this Lease.

          25.07. Headings. The article headings contained in this Lease are for
                 --------
convenience only and shall not enlarge or limit the scope or meaning of the
various and several articles hereof. Words in the singular number shall be held
to include the plural, unless the context otherwise requires. All agreements and
covenants herein contained shall be binding upon the respective heirs, personal
representatives, and successors and assigns of the parties thereto.

          25.08. Successors and Assigns. All agreements and covenants herein
                 ----------------------
contained shall be binding upon the respective heirs, personal representatives,
successors and assigns or the parties hereto. If there be more than one Tenant,
the obligations hereunder imposed upon Tenant shall be joint and several. If
there is a guarantor of Tenant's obligations hereunder, Tenant's obligations
shall be joint and several obligations of Tenant and such guarantor, and
Landlord need not first proceed against Tenant hereunder before proceeding
against such guarantor, and any such guarantor shall not be released from its
guarantee for any reason, including any amendment of this Lease, any forbearance
by Landlord or waiver of any of Landlord's rights, the failure to give Tenant or
such guarantor any notices, or the release of any party liable for the payment
or performance of Tenant's obligations hereunder. Notwithstanding the foregoing,
nothing contained in this Section 25.08 shall be deemed to override Article 8.

          25.09. Landlord's Representations. Neither Landlord nor Landlord's
                 --------------------------
agents or brokers have made any representations or promises with respect to the
Premises, the Building, the Parking Facilities, the Land, or any other portions
of the Project except as herein expressly set forth and all reliance with
respect to any representations or promises is based solely on those contained
herein. No rights, easements, or licenses are acquired by Tenant under this
Lease by implication or otherwise except as, and unless, expressly set forth in
this Lease.

          25.10. Entire Agreement; Amendments. This Lease and the Exhibits and
                 ----------------------------
Riders attached hereto set forth the entire agreement between the parties and
cancel all prior negotiations, arrangements, brochures, agreements, and
understandings, if any, between Landlord and Tenant regarding the subject matter
of this Lease. No amendment or modification of this Lease shall be binding or
valid unless expressed in writing executed by both parties hereto.

          25.11. Tenant's Authority. If Tenant signs as a corporation, execution
                 ------------------
hereof shall constitute a representation and warranty by Tenant that Tenant is a
duly organized and existing corporation, that Tenant has been and is qualified
to do business in the State of Texas and in good standing with the State of
Texas, that the corporation has full right and authority to enter into this
Lease, and that all persons signing on behalf of the corporation were authorized
to do so by appropriate corporate action. If Tenant signs as a partnership,
trust, or other legal entity, execution hereof shall constitute a representation
and warranty by Tenant that Tenant has complied with all applicable laws, rules,
and governmental regulations relative to Tenant's right to do business in the
State of Texas, that such entity has the full right and authority to enter into
this Lease, and that all persons signing on behalf of Tenant were authorized to
do so by any and all necessary or appropriate partnership, trust, or other
actions.

          25.12. Governing Law. This Lease shall be governed by and construed
                 -------------
under the laws of the State of Texas. Any action brought to enforce or interpret
this Lease shall be brought in the court of appropriate jurisdiction

                                      16
<PAGE>

in Travis County, Texas. Should any provision of this Lease require judicial
interpretation, Landlord and Tenant hereby agree and stipulate that the court
interpreting or considering same shall not apply the presumption that the terms
hereof shall be more strictly construed against a party by reason of any rule or
conclusion that a document should be construed more strictly against the party
who itself or through its agents prepared the same, it being agreed that all
parties hereto have participated in the preparation of this Lease and that each
party had full opportunity to consult legal counsel of its choice before the
execution of this Lease.

     25.13.  Tenant's Use of Name of the Building. Tenant shall not, without the
             ------------------------------------
prior written consent of Landlord, use the name of the Building for any purpose
other than as the address of the business to be conducted by Tenant in the
Premises, and Tenant shall not do or permit the doing of anything in connection
with Tenant's business or advertising (including brokers' flyers promoting
sublease space) which in the reasonable judgment of Landlord may reflect
unfavorably on Landlord or the Building or confuse or mislead the public as to
any apparent connection or relationship between Tenant and Landlord, the
Building, or the Land.

     25.14.  Ancient Lights. Any elimination or shutting off of light, air, or
             --------------
view by any structure which may be erected on lands adjacent to the Building
shall in no way affect this Lease and Landlord shall have no liability to Tenant
with respect thereto.

     25.15.  Changes to Project by Landlord. Landlord shall have the
             ------------------------------
unrestricted right to make changes to all portions of the Project in Landlord's
reasonable discretion for the purpose of improving access or security to the
Project or the flow of pedestrian and vehicular traffic therein. Landlord shall
have the right at any time, without the same constituting an actual or
constructive eviction and without incurring any liability to Tenant therefor, to
change the arrangement or location of entrances or passageways, doors and
doorways, corridors, elevators, stairs, bathrooms, or any other Common Areas so
long as reasonable access to the Premises remains available. Landlord shall also
have the right to (a) rearrange, change, expand or contract portions of the
Project constituting Common Areas (b) to use Common Areas while engaged in
making improvements, repairs or alterations to the Project, or any portion
thereof, and (c) to do and perform such other acts and make such other changes
in to or with respect to the Project, or any portion thereof, as Landlord may,
in the exercise of sound business judgment, deem to be appropriate. Landlord
shall be entitled to change the name or address of the Building or the Project.
Landlord shall have the right to close, from time to time, the Common Areas and
other portions of the Project for such temporary periods as Landlord deems
legally sufficient to evidence Landlord's ownership and control thereof and to
prevent any claim of adverse possession by, or any implied or actual dedication
to, the public or any party other than Landlord.

     25.16.  Time of Essence.  Time is of the essence of this Lease.
             ---------------

     25.17.  Landlord's Acceptance of Lease. The submission of this Lease to
             ------------------------------
Tenant shall not be construed as an offer and Tenant shall not have any rights
with respect thereto unless Landlord executes a copy of this Lease and delivers
the same to Tenant.

     25.18.  Financial Statements. At any time during the term of this Lease,
             ---------------------
Tenant shall, upon ten (10) days prior written notice from Landlord, provide
Landlord with a current financial statement and financial statements of the two
(2) years prior to the current financial statement year. Such statement shall be
prepared in accordance with generally accepted accounting principles and, if
such is the normal practice of Tenant, shall be audited by an independent
certified public accountant.

     25.19.  Monument Sign. Landlord intends to construct a monument sign near
             -------------
the Building, which monument sign is to be subject to the applicable codes of
the City of Austin. Landlord shall include Tenant's name and logo on such
monument sign so long as Tenant (as opposed to any assignee or subtenant) is in
occupancy of at least eighty-five percent (85%) of the original Premises and so
long as no Event of Default has occurred and is outstanding.


                                  ARTICLE 26

                             INTENTIONALLY DELETED

                                  ARTICLE 27

                               OTHER DEFINITIONS

         When used in this Lease, the terms set forth hereinbelow shall have the
following meanings: (a) "Business Days" shall mean Monday through Friday (except
for Holidays); "Business Hours" shall mean 8:00 a.m. to 7:00 p.m. on Monday
through Friday and 9:00 a.m. to 3:00 p.m. on Saturdays (except for Holidays);
and "Holidays" shall mean those holidays designated by Landlord, which holidays
shall be consistent with those holidays designated by landlords of other
first-class office buildings in the Austin, Texas suburban area. (b) "Common
Areas" shall mean those certain areas and facilities of the Building and the
Parking Facilities and those certain improvements to the Land which are from
time to time provided by Landlord for the use of tenants of the Building and
their employees, clients, customers, licensees and invitees or for use by the
public, which facilities and improvements include any and all corridors,
elevator foyers, vending areas, bathrooms, electrical and telephone rooms,
mechanical rooms, janitorial areas and other similar facilities of the Building
and of the Parking Facilities and any and all grounds, parks, landscaped areas,
outside sitting areas, sidewalks, walkways, and generally all other improvements
located on the Land, or which connect the Land to other buildings. (c) The words
"day" or "days" shall refer to calendar days, except where "Business Days" are
specified. (d) "Net Rentable Area" shall mean (1) in the case of a single
tenancy floor, all floor area measured from the inside surface of the outer
glass of the Building, excluding only the areas

                                      17


<PAGE>

("Service Areas") within the outside wall used for the Building's stairs, fire
towers, elevator shafts, vertical penetrations of the Building's central atrium,
flues, vents, stacks, pipe shafts, and vertical ducts (which areas shall be
measured from the mid-point of walls enclosing such areas, but including any
Service Areas which are for the specific use of the particular tenant, such as
special stairs or elevators, plus an allocation of the square footage of the
Building's central areas for providing telephone, electrical, mechanical,
janitorial, security and mail services, as well as, the central entry lobby,
ground level elevator lobby and service elevator lobby, central fire exit
corridors, service exit corridor and central loading dock (the "Central Areas"),
and (2) in the case of a floor to be occupied by more than one tenant, all floor
areas within the inside surface (with respect to the Premises) of the glass and
to the midpoint of the walls separating areas leased by or held for lease to
other tenants or from the Common Areas, but including a proportionate part of
the Common Areas located on such floor based upon the ratio which Tenant's Net
Rentable Area (excluding Common Areas) on such floor bears to the aggregate Net
Rentable Area (excluding Common Areas) on such floor, plus an allocation of the
square footage of the Building's Central Areas. In the case of both single and
multiple tenant floors, telephone, electrical, mechanical, maintenance,
janitorial or security rooms not included in the Building's Central Areas but
which serve more than one floor shall be considered Common Areas and shall be
allocated among all tenants whose premises are served thereby, regardless of
whether such premises are located on the same floor as the rooms in question.
Such allocation shall be made in accordance with the proportion of the Net
Rentable Area so served. No deductions from Net Rentable Area shall be made for
columns or projections necessary to the Building. (e) The "terms of this Lease"
shall be deemed to include all terms, covenants, conditions, provisions,
obligations, limitations, restrictions, reservations and agreements contained in
this Lease. (f) A "year" shall mean a calendar year.

         IN WITNESS WHEREOF, Landlord and Tenant have set their hands hereunto
and have caused this Lease to be executed by duly authorized officials thereof,
as of the day and year set forth on the cover page hereof.

LANDLORD:

PRENTISS PROPERTIES ACQUISITION PARTNERS, L.P.,
a Delaware limited partnership,

         By:      Prentiss Properties I, Inc.,
                  a Delaware corporation,
                  general partner


                                      By:  /s/  William J. Reister
                                         --------------------------------------
                                      Name:     William J. Reister
                                           ------------------------------------
                                      Title:    Vice President
                                            -----------------------------------


                                      By:  /s/  J. Kevan Dilbeck
                                         --------------------------------------
                                      Name:     J. Kevan Dilbeck
                                           ------------------------------------
                                      Title:    Senior Vice President
                                            -----------------------------------




TENANT:

VIGNETTE CORPORATION,
a Delaware corporation


                  By:   /s/ Joel G. Katz
                      --------------------------------------
                  Name:     Joel G. Katz
                       -------------------------------------
                  Title:    Chief Financial Officer
                        ------------------------------------



                                      18
<PAGE>

                                   EXHIBIT A

                          FLOOR PLAN OF THE PREMISES





                                       A
                                   Solo Page
<PAGE>

                                   EXHIBIT B

                                   THE LAND


Lot 2B, Replat of Lot 2, WALLINGWOOD SECTION II, a subdivision in Travis County,
Texas, according to the map or plat recorded in Book 100, Pages 95-96, Plat
Records of Travis County, Texas.



                                       B
                                   Solo Page
<PAGE>

                                   EXHIBIT C

                            LEASEHOLD IMPROVEMENTS



                                   ARTICLE 1

                                  DEFINITIONS

         The terms defined in Article 1 of this Exhibit C, for all purposes of
                                                ---------
this Exhibit C, shall have the meanings herein specified, and in addition to the
     ---------
terms defined herein, the definitions in the Basic Lease Information and
otherwise in this lease shall also apply to this Exhibit C.
                                                 ---------

         1.01. "Base Premises Condition" shall mean the condition of the
Premises to be completed by Landlord, at Landlord's sole cost, as more
particularly set forth on Attachment 1 to this Exhibit C.
                                               ---------

         1.02. "Building Standard" means the quality of materials, finishes, and
workmanship from time to time specified by Landlord for the Building.

         1.03. "Non-Building Standard" means all materials, finishes, and
workmanship used in connection with the construction and installation of the
Leasehold Improvements which deviate from Building Standard in terms of quality.

         1.04. "Tenant's Work" means the work which is supplied, installed, and
finished by Tenant's Contractor, at Tenant's cost, to complete any Leasehold
Improvements to the Premises.

         1.05. "Leasehold Improvements" shall mean the leasehold improvements to
be completed in the Premises.

         1.06. "Landlord's Space Planner" shall mean the architect or space
planner engaged by Landlord to prepare the plans and specifications for the
Leasehold Improvements as contemplated by Article 2 hereof. Tenant shall have
the option of selecting the architect or space planner that will act as
Landlord's Space Planner, provided, such architect or space planner must be
reasonably acceptable to Landlord.

         1.07. "Tenant's Contractor" means the person or firm from time to time
selected, and paid, by Tenant, but approved by Landlord, in Landlord's
reasonable discretion, to construct and install the Leasehold Improvements in
the Premises. Landlord reserves the right to approve (a) the insurance
maintained by Tenant's Contractor, which approval shall include the insurance
carriers and underwriters, and (b) all subcontractors to be retained by Tenant's
Contractors with respect to Tenant's Work. If, but only if, Tenant provides
payment and performance bonds reasonably acceptable to Landlord (which bonds
must be reasonably acceptable to Landlord as to amounts, sureties and form),
Tenant may act as Tenant's Contractor.

         1.08. "Landlord's Manager" shall be the manager of the Building, whose
responsibilities include serving as construction manager for Tenant in
connection with the construction of the Leasehold Improvements.

         1.09. "Tenant Expenditure Authorization" means an authorization by
Tenant, prior to the commencement of any Tenant's Work for Landlord's Manager to
contract to expend funds on behalf of Tenant. Landlord shall be named an
additional insured on the insurance maintained by Tenant's Contractor.

                                   ARTICLE 2

                            COMPLETION OF PREMISES

         2.01. As soon as practicable after the execution of this Lease, but in
any event not more than sixty (60) days from the date of execution of this
Lease, Tenant, at Tenant's expense, shall provide Landlord's Space Planner with
sufficient instructions and information to enable Landlord's Space Planner to
prepare and complete the space plan, the architectural construction plan to
include specifications and finish schedules specifications (collectively "Plans
and Specifications") for the Leasehold Improvements. Such Plans and
Specifications shall be prepared by Landlord's Space Planner and submitted,
together with the Tenant Expenditure Authorization, which has been prepared by
Landlord's Manager, to Tenant for its approval. Within ten (10) working days
after Tenant's receipt of such Plans and Specifications and the Tenant
Expenditure Authorization, Tenant shall notify Landlord's Manager in writing as
to whether Tenant approves or disapproves such Plans and Specifications and the
Tenant Expenditure Authorization. Landlord's approval of the Plans and
Specifications, and any changes thereto, for Tenant's Work shall impose no
responsibility or liability on Landlord for their completeness, design
sufficiency, or compliance with all applicable laws, rules and regulations of
governmental agencies or authorities. If Tenant fails to expressly disapprove
such Plans and Specifications and the Tenant Expenditure Authorization, within
this ten (10) day period, then Landlord's Manager shall be authorized to proceed
thereon. All costs, including professional fees, of Landlord's Space Planner
which are related to the review of Tenant's information and instructions and the
preparation of the space plan and the Plans and Specifications shall be paid by
Landlord, subject to Tenant's Allowance.

         2.02. Unless otherwise agreed to in writing by Landlord and Tenant, all
Tenant's Work involved in the construction and installation of the Leasehold
Improvements shall be carried out by Tenant's Contractor under the sole
direction of Landlord's Manager, who shall serve as construction manager on
behalf of Tenant. Tenant shall cooperate with Landlord and Landlord's Space
Planner to promote the efficient and expeditious completion of such


                                       C
                                  Page 1 of 2
<PAGE>

Tenant's Work. To the extent that the cost of Tenant's Work exceeds Tenant's
Allowance (as hereinafter defined), Tenant agrees to pay, promptly upon being
billed therefor, the amount by which the cost (labor and materials) of all
Tenant's Work, together with a fee equal to one percent (1%) of the costs of
construction of the Leasehold Improvements to Landlord's Manager as compensation
for Landlord's Manager's supervision of the construction, alteration, and
installation of the Leasehold Improvements exceeds Tenant's Allowance (the
"Excess Costs"). Tenant shall pay 50% of the Excess Costs to Landlord's Manager
in trust prior to commencement of Tenant's Work, which payments shall be applied
by Landlord's Manager to the payment of the Excess Costs at such time as Tenant
has paid 50% of the Excess Costs from its own funds in accordance with the
monthly statements to be delivered by Landlord's Manager to Tenant pursuant to
this Section 2.02. Tenant's Contractor shall not commence Tenant's Work without
payment in trust to Landlord's Manager of 50% of the Excess Costs. Landlord's
Manager shall submit monthly statements of Excess Costs incurred to Tenant,
which statements shall reflect Tenant's prorata portion of such statement.
Tenant shall promptly pay Tenant's prorata portion of such statement, with the
final payment to be due on or before Tenant occupies the Premises. Tenant agrees
that in the event of default of payment thereof, Landlord (in addition to all
other remedies) shall have the same rights as in the event of default of payment
of Rent under this Lease.

         2.03. If there are any changes in the Leasehold Improvements caused by
Tenant from the work as reflected in the final Plans and Specifications, each
such change must receive the prior written approval of the Landlord, and, in the
event of any such approved change in the Plans and Specifications, drawings,
Tenant shall, upon completion of the Tenant's Work, furnish Landlord with an
accurate "as-built" plan of the Tenant's Work as constructed, which plans shall
be incorporated in to this Exhibit C by this reference for all intents and
                           ---------
purposes when said plans are fully completed.

         2.04. All design, construction and installation shall conform to the
requirements of applicable building, plumbing and electrical codes, requirements
of governmental laws, including the Americans with Disabilities Act, and the
requirements of any authority having jurisdiction over, or with respect to, such
work.

         2.05. Tenant acknowledges that the Premises shall be delivered to
Tenant's Contractor in "as is" Base Premises Condition.

         2.06  Tenant shall not be charged for the use of elevators or utilities
prior to the Commencement Date during the period of the construction of Tenant's
Work and Tenant's relocation to the Premises.

                                   ARTICLE 3

                              TENANT'S ALLOWANCE

         3.01. Landlord hereby grants Tenant an allowance equal to $1,016,106.00
("Tenant's Allowance") to be used towards the cost of Tenant's Work for the
Premises and Tenant's costs associated with its relocation to the Premises. In
the event that the full amount of Tenant's Allowance is not expended on the
costs of Landlord's Space Planner, the cost of Tenant's Work, including the fee
to Landlord's Manager for supervising Tenant's Work and Tenant's costs
associated with its relocation to the Premises, Tenant may apply any remaining
monies against Base Rent to be due under the Lease.

                                   ARTICLE 4

                             COMMENCEMENT OF RENT

         4.01. Tenant's obligation for the payment of the Rent under this Lease
for the Premises shall commence in accordance with Section 3.02 of the Lease;
provided, however, that if such substantial completion is delayed as a result
of: (a) Tenant's failure to approve all the Plans and Specifications as required
by Section 2.01 of this Exhibit C, (b) Tenant's changes in any Plans and
                        ---------
Specifications, (c) Tenant's request for materials, finishes or installations
other than Building Standard, (d) Tenant's disapproval, or failure to approve,
the Tenant Expenditure Authorization as required by Section 2.01 of this Exhibit
                                                                         -------
C, or (e) Tenant's failure to timely pay the 50% portion of costs in excess of
-
Tenant's Allowance as required pursuant to Section 2.02 of this Exhibit C, then
                                                                ---------
Tenant's obligation to pay Rent under this lease shall be accelerated by the
number of days of such Tenant Delay (herein so called).


                                       C
                                  Page 2 of 2
<PAGE>

                                 ATTACHMENT 1
                                 TO EXHIBIT C

                            BASE PREMISES CONDITION


"Base Premises Condition" shall mean the condition of the Premises completed
with the following improvements:

 1.      Premises dried in and weather tight.

 2.      Outside walls, core walls, columns on each floor on which the Premises
         are located completed to Building Standard condition for public areas.

 3.      Broom clean unfinished concrete floors throughout the Premises,
         completed to a tolerance of 1/4inch per 10 feet.

 4.      Building Standard ceiling grid system installed and 2 foot by 4 foot
         ceiling tile stacked on the floor.

 5.      110 Volt 20 Amp power supplied to the Building core, at panels in the
         electrical closet.

 6.      Exterior main heating, ventilating, and air conditioning ducts
         completed to the mixing boxes.

 7.      Sprinkler risers and main loop on each floor with sprinkler heads
         turned up at ratio of 1 per 225 usable square feet.

 8.      Building Standard smoke detectors in accordance with applicable shell
         building codes.

 9.      Building Standard lights, stacked on the floor, at a ratio of 1 per 100
         usable square feet.

10.      Shell building, exit lights and fire alarms installed.

11.      Sound insulation at core.

12.      Access to core to domestic cold water, waste and vent systems.

13.      Building Standard telephone closets and telephone boards installed one
         (1) per each floor and finished in sheetrock.

14.      All core walls taped and bedded.




                                 Attachment 1
                                  Solo Page
<PAGE>

                                   EXHIBIT D

                          FORM OF COMMENCEMENT NOTICE


        This Commencement Notice is delivered this _____ day of _____________,
19____, by Prentiss Properties Acquisition Partners, L.P., a Delaware limited
partnership ("Landlord"), to _____________________ ("Tenant"), pursuant to the
provisions of Section 3.03 of that certain Lease Agreement (the "Lease") dated
_____________, 19____, by and between Landlord and Tenant covering certain space
in the Building known as _____________________. All terms used herein with their
initial letter capitalized shall have the meaning assigned to such terms in the
Lease.

                             W I T N E S S E T H:

         1.  The Building, the Premises, the Parking Facilities, and all other
improvements required to be constructed and furnished by Landlord in accordance
with the terms of the Lease have been satisfactorily completed by the Landlord
and accepted by the Tenant.

         2.  The Premises have been delivered to, and accepted by, the Tenant,
subject to the completion of "punch list" items.

         3.  The Commencement Date of the Lease is the ____ day of ____________,
19___, and the Expiration Date is the ____ day of ____________, 20____.

         4.  The Premises consist of ________ square feet of Net Rentable Area
located on the ____ floor of the Building.

         5.  The Base Rent is $________ per annum and Tenant's Operating Costs
Payment is $________ per annum, payable in monthly installments of $________,
subject, however, to the provisions of the Lease relating to adjustments of
Tenant's Operating Costs Payment beginning on January 1, 2000.

         6.  Remittance of the foregoing payments shall be made on the first day
of each month in accordance with the terms and conditions of the Lease at the
following address:

                Prentiss Properties Acquisition Partners, L.P.
                     3890 W. Northwest Highway, Suite 400
                              Dallas, Texas 75220

         IN WITNESS WHEREOF, this instrument has been duly executed by Landlord
as of the date first written above.

LANDLORD:

Prentiss Properties Acquisition Partners, L.P.,
a Delaware limited partnership,


         By:      Prentiss Properties I, Inc.,
                  an Delaware corporation,
                  general partner


                  By:    ________________________
                  Name:  ________________________
                  Title: ________________________



                  By:    ________________________
                  Name:  ________________________
                  Title: ________________________



                                       D
                                   Solo Page
<PAGE>

                                   RIDER NO. 1

                              RULES AND REGULATIONS

         1. Sidewalks, doorways, vestibules, halls, stairways and similar areas
shall not be obstructed by tenants or their officers, agents, servants, and
employees, or used for any purpose other than ingress and egress to and from the
Premises and for going from one part of the Building to another part of the
Building.

         2. Plumbing fixtures and appliances shall be used only for the purpose
for which constructed, and no sweepings, rubbish, rags, or other unsuitable
material shall be thrown or placed therein. The cost of repairing any stoppage
or damage resulting to any such fixtures or appliances from misuse on the part
of a tenant or such tenant's officers, agents, servants, and employees shall be
paid by such tenant.

         3. No signs, posters, advertisements, or notices shall be painted or
affixed on any of the windows or doors, or other part of the Building, except of
such color, size, and style, and in such places, as shall be first approved in
writing by the building manager. No nails, hooks, or screws shall be driven into
or inserted in any part of the Building, except by Building maintenance
personnel.

         4. Directories will be placed by Landlord, at Landlord's own expense,
in the lobby of the Building. No other directories shall be permitted.

         5. The Premises shall not be used for conducting any barter, trade, or
exchange of goods or sale through promotional give-away gimmicks or any business
involving the sale of second-hand goods, insurance salvage stock, or fire sale
stock, and shall not be used for any auction or pawnshop business, any fire
sale, bankruptcy sale, going-out-of- business sale, moving sale, bulk sale, or
any other business which, because of merchandising methods or otherwise, would
tend to lower the first-class character of the Building.

         6. Tenants shall not do anything, or permit anything to be done, in or
about the Building, or bring or keep anything therein, that will in any way
increase the possibility of fire or other casualty or obstruct or interfere with
the rights of, or otherwise injure or annoy, other tenants, or do anything in
conflict with the valid pertinent laws, rules, or regulations of any
governmental authority.

         7. Tenant shall not place a load upon any floor of the premises which
exceeds to floor load per square foot which such floor was designed to carry or
which is allowed by applicable building code. Landlord may prescribe the weight
and position of all safes and heavy installations which Tenant desires to place
in the premises so as properly to distribute the weight thereof. All damage done
to the Building by the improper placing of heavy items which overstress the
floor will be repaired at the sole expense of the Tenant.

         8. A tenant shall notify the building manager when safes or other heavy
equipment are to be taken into or out of the Building. Moving of such items
shall be done under the supervision of the building manager, after receiving
written permission from him/her.

         9. Corridor doors, when not in use, shall be kept closed.

        10. All deliveries must be made via the service entrance and service
elevators during normal business hours or as otherwise directed or scheduled by
Landlord. Prior approval must be obtained from Landlord for any deliveries that
must be received after normal business hours.

        11. Each tenant shall cooperate with building employees in keeping the
premises neat and clean.

        12. Nothing shall be swept or thrown into the corridors, halls,
elevator shafts, or stairways. No birds, animals, or reptiles, or any other
creatures, shall be brought into or kept in or about the building.

        13. Should a tenant require telegraphic, telephonic, annunciator, or
any other communication service, Landlord will direct the electricians and
installers where and how the wires are to be introduced and placed, and none
shall be introduced or placed except as Landlord shall direct.

        14. Tenants shall not make or permit any improper noises in the
Building, or otherwise interfere in any way with other tenants or persons having
business with them.

        15. No equipment of any kind shall be operated on the premises that
could in any way annoy any other tenant in the Building without written consent
of Landlord.

        16. Business machines and mechanical equipment belonging to Tenant
which cause noise and/or vibration that may be transmitted to the structure of
the Building or to any leased space so as to be objectionable to Landlord or any
tenants in the Building shall be placed and maintained by Tenant, at Tenant's
expense, in setting of cork, rubber, or spring type noise and/or vibration
eliminators sufficient to eliminate vibration and/or noise.

        17. Tenants shall not use or keep in the Building any inflammable or
explosive fluid or substance, or any illuminating material, unless it is battery
powered, UL approved.

        18. Tenants employees or agents, or anyone else who desires to enter
the Building after normal business hours, may be required to provide appropriate
identification and sign in upon entry, and sign out upon


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leaving, giving the location during such person's stay and such person's time of
arrival and departure, and shall otherwise comply with any reasonable access
control procedures as Landlord may from time to time institute.

         19.  Landlord has the right to evacuate the Building in event of
emergency or catastrophe.

         20.  If any governmental license or permit shall be required for the
proper and lawful conduct of Tenant's business, Tenant, before occupying the
Premises, shall procure and maintain such license or permit and submit it for
Landlord's inspection. Tenant shall at all times comply with the terms of any
such license or permit.

         21.  Landlord shall have the right, exercisable without notice and
without liability to any tenant, to change the name and street address of the
Building.

         22.  Neither Tenant, nor any other person visiting the Building shall
be permitted to use tobacco products in the Building, Premises, or the Common
Areas.

         23.  Landlord reserves the right to rescind any of these Rules and
Regulations and make such other and further rules and regulations or
modifications to these rules and regulations.

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                                  RIDER NO. 2

                               EXTENSION OPTION

         Tenant shall have the right to extend the original term of this Lease
(the "Original Term") for one (1) period of five (5) years, (the "Extension
Term"), upon and subject to the following terms and conditions:

         1. If Tenant so elects to extend the Term for the Extension Term,
Tenant shall give written notice thereof to Landlord no earlier than twelve (12)
months and no later than nine (9) months prior to the expiration of the Original
Term. Following receipt of such written notice by Landlord (but in no event
earlier than twelve (12) months prior to the expiration of the Original Term),
Landlord and Tenant shall endeavor to agree upon the Fair Market Value Rate (as
defined in paragraph 3 hereof) within thirty (30) days after the date of
Tenant's delivery of written notice electing to extend the Term for the
Extension Term. If Landlord and Tenant fail to agree upon the Fair Market Value
Rate by the expiration of such thirty (30) day period, Tenant's exercise shall
be null and void. If Landlord and Tenant agree upon such Fair Market Value Rate,
this Lease, subject to the provisions of this Rider No. 2, shall be
automatically extended for the Extension Term with the same force and effect as
if the Extension Term had been originally included in the Original Term, upon
the same terms and conditions as in this Lease, except that (a) the Base Rent
shall be as set forth in paragraph 3 below, and (b) the terms of the Lease
relating to Landlord's obligations to construct leasehold improvements
(including Exhibit C) shall be of no force or effect and Tenant shall be deemed
           ---------
to accept the Premises in its "as is" condition, unless Landlord and Tenant
mutually agree upon an improvement or refurbishment allowance.

         2. Tenant's right to extend the Term for the Extension Term shall be of
no force or effect if either at the time of exercise of the extension option, in
question, or at the time of commencement of the Extension Term either (a) an
Event of Default then exists, or (b) Tenant (as opposed to any assignee or
subtenant) is not in occupancy of at least eighty-five percent (85%) of the
original Premises).

         3. Base Rent for the Premises shall be an amount equal to the Fair
Market Value Rate (as defined below), multiplied by the Net Rentable Area of the
Premises. For purposes hereof the "Fair Market Value Rate" means the fair market
rental rate per square foot of Net Rentable Area of the Premises (taking into
account the "as is" condition of the Premises, the adjustment of Base Year
Operating Costs to the calendar year that the Extension Term commences, all rent
concessions and inducements), for a comparable lease term to comparable tenants
for space of comparable size in comparable buildings with comparable quality of
finish out in the Austin, Texas suburban area, but in no event less than the
Base Rent and Tenant's Operating Costs Payment payable during the last month of
the Original Term.

         4. Upon the exercise by Tenant of its option in respect of the
Extension Term, the term "Term", as otherwise defined and used in the Lease,
shall mean the Term, as extended for the Extension Term, and the term
"Expiration Date", as otherwise defined and used in the Lease, shall mean the
date of expiration of the Extension Term.

         5. Any termination, cancellation or surrender of this Lease shall
terminate any right of extension for the Extension Term in respect of the
portion of the Premises as to which this Lease is terminated, canceled or
surrendered.

         6. Time shall be of the essence with respect to the exercise by Tenant
of its option under this Rider No. 2 .

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