<PAGE>   1

                                                                    EXHIBIT 10.5



                                  OFFICE LEASE

                                     between

 OTR, AN OHIO GENERAL PARTNERSHIP, AS NOMINEE OF THE STATE TEACHERS RETIREMENT
      BOARD OF OHIO, A STATUTORY ORGANIZATION CREATED BY THE LAWS OF OHIO

                                   (Landlord)

                                      and

                               CHEMCONNECT, INC.

                             a Delaware Corporation

                                    (Tenant)

                                  for Premises

                              44 Montgomery Street
                           San Francisco, California


<PAGE>   2

                                TABLE OF CONTENTS


<TABLE>
<CAPTION>
<S>                                                                                               <C>
ARTICLE I - SUMMARY AND CERTAIN DEFINITIONS.................................................       1
        1.1  Building.......................................................................       1
        1.2  Premises.......................................................................       1
        1.3  Rentable Area of the Premises..................................................       1
        1.4  Lease Year.....................................................................       1
        1.5  Lease Term.....................................................................       1
        1.6  Commencement Date..............................................................       1
        1.7  Expiration Date................................................................       1
        1.8  Base Rent......................................................................       1
        1.9  Tenant's Percentage Share......................................................       1
        1.10  Security Deposit..............................................................       1
        1.11  Tenant's Permitted Use........................................................       1
        1.12  Business Hours................................................................       1
        1.13  Landlord's Address For Notices................................................       1
        1.14  Tenant's Address For Notices..................................................       2
        1.15  Brokers.......................................................................       2
        1.16  Guarantors....................................................................       2

ARTICLE II - PREMISES.......................................................................       2
        2.1  Lease of Premises..............................................................       2
        2.2  Acceptance of Premises.........................................................       2

ARTICLE III - PREMISES......................................................................       2
        3.1  Term...........................................................................       2

ARTICLE IV - RENTAL.........................................................................       2
        4.1  Definitions....................................................................       2
             4.1.1  Base Year...............................................................       2
             4.1.2  Property Taxes..........................................................       2
             4.1.3  Operating Expenses......................................................       4
             4.1.4  Exclusions from Operating Expenses......................................       4
             4.1.5  Adjustment..............................................................       4
        4.2  Base Rent......................................................................       4
             4.2.1  Rent Adjustment.........................................................       4
             4.2.2  Tax and Operating Expense Adjustment....................................       4
             4.2.3  Tax Exempt Tenant.......................................................       4
        4.3  Adjustment Procedure; Estimates................................................       5
             4.3.1  Estimates...............................................................       5
             4.3.2  Landlord's Statement....................................................       5
             4.3.3  Termination.............................................................       5
        4.4  Review of Landlord's Statement.................................................       5
             4.4.1  Notice..................................................................       6
             4.4.2  Records.................................................................       6
             4.4.3  Landlord's Review; Reconciliation.......................................       6
        4.5  Payment........................................................................       6
        4.6  Late Charge; Interest..........................................................       6
        4.7  Additional Rent................................................................       7
        4.8  Additional Taxes...............................................................       7

ARTICLE V - SECURITY DEPOSIT................................................................       7

ARTICLE VI - USE OF PREMISES................................................................       7
        6.1  Tenant's Permitted Use.........................................................       7
        6.2  Compliance With Laws and Other Requirements....................................       7
             6.2.1  Applicable Law..........................................................       7
             6.2.2  No Violation............................................................       7
        6.3  Hazardous Materials............................................................       8
             6.3.1  Prohibition.............................................................       8
             6.3.2  Remediation.............................................................       8
             6.3.3  Additional Documents....................................................       8
</TABLE>

                                       i
<PAGE>   3
<TABLE>
<CAPTION>
<S>                                                                                               <C>
             6.3.4  Environmental Laws......................................................       8
             6.3.5  Hazardous Materials.....................................................       8
             6.3.6  Handle..................................................................       8
             6.3.7  Regulatory Authority....................................................       8

ARTICLE VII - UTILITIES AND SERVICES........................................................       9
        7.1  Building Services..............................................................       9
             7.1.1  Elevator Service........................................................       9
             7.1.2  HVAC....................................................................       9
             7.1.3  Water...................................................................       9
             7.1.4  Janitorial and Cleaning.................................................       9
             7.1.5  Electricity.............................................................       9
             7.1.6  Payments................................................................       9
        7.2  Interruption of Service........................................................      10
        7.3  Utility Deregulation...........................................................      10

ARTICLE VIII - MAINTENANCE AND REPAIRS......................................................      10
        8.1  Landlord's Obligations.........................................................      10
        8.2  Tenant's Obligations...........................................................      10
        8.3  Landlord's Rights..............................................................      11

ARTICLE IX - ALTERATIONS, ADDITIONS AND IMPROVEMENTS........................................      11
        9.1  Landlord's Consent; Conditions.................................................      11
        9.2  Performance of Alterations Work................................................      11
        9.3  Liens..........................................................................      11
        9.4  Lease Termination..............................................................      12

ARTICLE X - INDEMNIFICATION AND INSURANCE...................................................      12
        10.1  Indemnification...............................................................      12
             10.1.1  Tenant.................................................................      12
             10.1.2  Landlord...............................................................      13
             10.1.3  No Limitation..........................................................      13
        10.2  Property Insurance............................................................      13
             10.2.1  Tenant All-Risk........................................................      13
             10.2.2  Tenant Business Interruption...........................................      13
             10.2.3  Landlord All-Risk......................................................      13
        10.3  Liability Insurance...........................................................      13
             10.3.1  Tenant.................................................................      13
             10.3.2  Alcohol................................................................      13
             10.3.3  Estimates..............................................................      14
        10.4  Workers' Compensation Insurance...............................................      14
        10.5  Policy Requirements...........................................................      14
        10.6  Waiver of Subrogation.........................................................      14
        10.7  Failure to Insure.............................................................      14

ARTICLE XI - DAMAGE OR DESTRUCTION..........................................................      14
        11.1  Total Destruction.............................................................      14
        11.2  Partial Destruction of Premises...............................................      14
        11.3  Exceptions to Landlord's Obligations..........................................      15
        11.4  Waiver........................................................................      15

ARTICLE XII - CONDEMNATION..................................................................      15
        12.1  Taking........................................................................      15
        12.2  Award.........................................................................      15
        12.3  Temporary Taking..............................................................      15

ARTICLE XIII - RELOCATION...................................................................      15

ARTICLE XIV - ASSIGNMENT AND SUBLETTING.....................................................      15
        14.1  Restriction...................................................................      15
        14.2  Notice to Landlord............................................................      16
             14.2.1  Statement..............................................................      16
             14.2.2  Original Documents.....................................................      16
</TABLE>


<PAGE>   4

<TABLE>
<CAPTION>
<S>                                                                                              <C>
        14.3  Landlord's Recapture Rights...................................................      16
        14.4  Landlord's Consent; Standards.................................................      16
        14.5  Additional Rent...............................................................      17
        14.6  Landlord's Costs..............................................................      17
        14.7  Continuing Liability of Tenant................................................      17
        14.8  Non-Waiver....................................................................      17

ARTICLE XV - DEFAULT AND REMEDIES...........................................................      17
        15.1  Events of Default By Tenant...................................................      17
             15.1.1  Failure to Pay Rent....................................................      17
             15.1.2  Abandonment............................................................      17
             15.1.3  Failure to Perform.....................................................      18
             15.1.4  Bankruptcy.............................................................      18
             15.1.5  Misstatement...........................................................      18
        15.2  Landlord's Right To Terminate Upon Tenant Default.............................      18
        15.3  Mitigation of Damages.........................................................      18
        15.4  Landlord's Right to Continue Lease Upon Tenant Default........................      19
        15.5  Right of Landlord to Perform..................................................      19
        15.6  Default Under Other Leases....................................................      19
        15.7  Non-Waiver....................................................................      19
        15.8  Cumulative Remedies...........................................................      19
        15.9  Default by Landlord...........................................................      20

ARTICLE XVI - ATTORNEYS' FEES; INDEMNIFICATION..............................................      20
        16.1  Attorneys' Fees...............................................................      20
        16.2  Indemnification...............................................................      20

ARTICLE XVII - SUBORDINATION AND ATTORNMENT.................................................      20
        17.1  Subordination.................................................................      20
        17.2  Attornment....................................................................      21
        17.3  Mortgagee Protection..........................................................      21

ARTICLE XVIII - MISCELLANEOUS...............................................................      21
        18.1  Quiet Enjoyment...............................................................      21
        18.2  Rules and Regulations.........................................................      21
        18.3  Estoppel Certificates.........................................................      22
        18.4  Entry by Landlord.............................................................      22
        18.5  Landlord's Lease Undertakings.................................................      22
        18.6  Transfer of Landlord's Interest...............................................      23
        18.7  Holdover......................................................................      23
        18.8  Notices.......................................................................      23
        18.9  Brokers.......................................................................      23
        18.10  Communications and Computer Lines............................................      24
             18.10.1  New Lines.............................................................      24
             18.10.2  Line Problems.........................................................      24
        18.11  Entire Agreement.............................................................      24
        18.12  Amendments...................................................................      24
        18.13  Successors...................................................................      24
        18.14  Force Majeure................................................................      24
        18.15  Survival of Obligations......................................................      24
        18.16  Light and Air................................................................      25
        18.17  Governing Law................................................................      25
        18.18  Severability.................................................................      25
        18.19  Captions.....................................................................      25
        18.20  Interpretation...............................................................      25
        18.21  Independent Covenants........................................................      25
        18.22  Number and Gender............................................................      25
        18.23  Time is of the Essence.......................................................      25
        18.24  Joint and Several Liability..................................................      25
        18.25  Exhibits.....................................................................      25
        18.26  Offer to Lease...............................................................      25
        18.27  No Counterclaim; Choice of Laws..............................................      25
        18.28  Rights Reserved by Landlord..................................................      25
</TABLE>
<PAGE>   5

<TABLE>
<CAPTION>
<S>                                                                                               <C>
        18.29  Asbestos.....................................................................      26
        18.30  ADR Process..................................................................      26
        18.31  Miscellaneous Signage........................................................      27
</TABLE>

                                    EXHIBITS

<TABLE>
<CAPTION>
<S>              <C>
Exhibit A        Floor Plan of Premises
Exhibit B        Work Letter Agreement
Exhibit C        Rules and Regulations
Exhibit D        None
Exhibit E        Acceptance Letter
</TABLE>


<PAGE>   6

                                  OFFICE LEASE


        THIS OFFICE LEASE ("Lease"), dated September 20, 1999, is made and
entered into by and between OTR, AN OHIO GENERAL PARTNERSHIP, as Nominee of The
State Teachers Retirement Board of Ohio, a statutory organization created by the
laws of Ohio ("Landlord"), and CHEMCONNECT, INC. a Delaware corporation
("Tenant") upon the following terms and conditions:

        ARTICLE I - SUMMARY AND CERTAIN DEFINITIONS

        Unless the context otherwise specifies or requires, the following terms
shall have the meanings specified herein:

        1.1 BUILDING. The term "Building" shall mean that certain office
building located at 44 Montgomery Street in San Francisco, California, commonly
known as 44 MONTGOMERY STREET together with any related land, improvements,
common areas, driveways, sidewalks and landscaping.

        1.2 PREMISES. The term "Premises" shall mean Suite 280 in the Building,
as more particularly outlined on the "Floor Plan" attached hereto as Exhibit "A"
and incorporated herein by reference. As used herein, "Promises" shall not
include any storage area in the Building or rooftop area on the Building, which
areas shall (if applicable) be leased or rented pursuant to separate written
agreements.

        1.3 RENTABLE AREA OF THE PREMISES. The term "Rentable Area of the
Premises" shall mean One Thousand Three Hundred and Twenty Eight (1,328) square
feet, which Landlord and Tenant have stipulated as the Rentable Area of the
Premises.

        1.4 LEASE YEAR. The term "Lease Year" shall mean such consecutive twelve
(12) month period following the Commencement Date.

        1.5 LEASE TERM. The term of this Lease ("Lease Term") shall be for a
period of two consecutive Lease Years one month and seventeen days following the
Commencement Date, unless sooner terminated as otherwise provided in this Lease.

        1.6 COMMENCEMENT DATE. Subject to adjustment as provided in Section 3.1,
the term "Commencement Date" shall mean the sooner of October 15, 1999, or upon
occupancy of the Premises.

        1.7 EXPIRATION DATE. Subject to adjustment as provided in Section 3.1,
the term "Expiration Date" shall mean December 31, 2001.

        1.8 BASE RENT. Subject to adjustment as provided in Article 4, the term
"Base Rent" shall mean the following amounts for the following periods:

<TABLE>
<CAPTION>
Period                Monthly Base Rent      Annual Rate/RSF       Annual Base Rent
------                -----------------      ---------------       ----------------
<S>                      <C>                    <C>                   <C>
10/15/99-11/30/00        $3,873.33              $35.00                $46,480.00
12/01/00-12/31/01        $4,094.67              $37.00                $49,136.00
</TABLE>

        1.9 TENANT'S PERCENTAGE SHARE. Subject to adjustment by Acceptance
letter, the term "Tenant's Percentage Share" shall mean 0.21% with respect to
increases in Property Taxes and Operating Expenses (as such terms are
hereinafter defined). Landlord may reasonably recompute Tenant's Percentage
Share from time to time to reflect reconfigurations, additions or modifications
to the Premises or Building.

        1.10 SECURITY DEPOSIT. The term "Security Deposit" shall mean $5,000
delivered by Tenant to Landlord to secure Tenant's performance of its
obligations hereunder.

        1.11 TENANT'S PERMITTED USE. The term "Tenant's Permitted Use" shall
mean general and administrative office use, and no other use.

        1.12 BUSINESS HOURS. The term "Business Hours" shall mean the hours of
8:00 A.M. to 6:00 P.M., Monday through Friday, and 9:00 A.M. to 1:00 P.M.,
Saturdays (federal and state holidays excepted). "Holidays" are defined to be
the following days: New Years Day,



                                       1
<PAGE>   7

Memorial Day, Independence Day, Labor Day, Thanksgiving Day and Christmas Day,
and to the extent of utilities or services provided by union members engaged at
the Building, such other holidays observed by such unions.

        1.13 LANDLORD'S ADDRESS FOR NOTICES. The term "Landlord's Address for
Notices" shall mean OTR c/o Seagate Properties, Inc., 44 Montgomery Street,
Suite 1710, San Francisco, California 94104, Attn: Property Manager, with a copy
(but which copy shall not constitute notice) to OTR, 275 Broad Street, Columbus,
Ohio, Attn: Director, Real Estate.

        1.14 TENANT'S ADDRESS FOR NOTICES. The term "Tenant's Address for
Notices" shall mean 44 Montgomery Street, Suite 250, San Francisco, CA 94104.

        1.15 BROKERS. The term "Brokers" shall mean Seagate Properties, Inc.

        1.16 GUARANTORS. The term "Guarantors" shall not be applicable to this
Lease.

                            ARTICLE II --- PREMISES

        2.1 LEASE OF PREMISES. Commencing on the Commencement Date, Landlord
agrees to and shall lease the Premises to Tenant, and Tenant agrees to and shall
lease and hire the Premises from Landlord, upon all of the terms, covenants and
conditions contained in this Lease.

        2.2 ACCEPTANCE OF PREMISES. Unless otherwise specifically set forth in
this Lease, Tenant acknowledges that Landlord has not made any representation or
warranty with respect to the condition of the Premises or the Building or with
respect to the suitability or fitness of either for the conduct of Tenant's
Permitted Use or for any other purpose. Prior to Tenant's taking possession of
the Premises, Landlord or its designee and Tenant will walk the Premises for the
purpose of reviewing the condition of the Premises. Within ten (10) business
days after such review, Landlord and Tenant shall execute and deliver to each
other duplicate original counterparts of the Acceptance Letter. Except as is
expressly set forth in this Lease or Work Letter Agreement, or as may be
expressly set forth in the Acceptance Letter, Tenant agrees to accept the
Premises in its "as is" physical condition without any agreements,
representations, understandings or obligations on the part of Landlord to
perform any alterations, repairs or improvements (or to provide any allowance
for same). Notwithstanding the foregoing, Landlord represents that as of the
Commencement Date, all Building operating systems pertinent to the Premises are
in good working repair.

                            ARTICLE III --- PREMISES

        3.1 TERM. Except as otherwise provided in this Lease, the Lease Term
shall be for the period described in Section l.5 of this Lease, commencing on
the Commencement Date described in Section 1.6 of this Lease and ending on the
Expiration Date described in Section 1.7 of this Lease; provided, however, that,
for any reason, Landlord is unable to deliver possession of the Premises on the
date described in Section 1.6 of this Lease, Landlord shall not be liable for
any damage caused thereby, nor shall the Lease be void or voidable, but, rather,
the Lease Term shall commence upon, and the Commencement Date shall be the date
that possession of the Premises is so tendered to Tenant (except for
Tenant-caused delays which shall not be deemed to delay commencement of the
Lease Term), and, unless Landlord elects otherwise, the Expiration Date
described in Section 1.7 of this Lease shall be extended by an equal number of
days.

                             ARTICLE IV --- RENTAL

        4.1 DEFINITIONS. Unless the context otherwise specifies or requires, the
following terms shall have the meanings specified herein:

             4.1.1. Base Year. The term "Base Year" shall mean calendar year
2000.

             4.1.2. Property Taxes. The term "Property Taxes" shall mean the
aggregate amount of all real estate taxes, assessments (whether they be general
or special), sewer rents and charges, transit taxes, taxes based upon the
receipt of rent and any other federal, state or local governmental charge,
general, special, ordinary or extraordinary (but not including income or
franchise taxes, capital stock, inheritance, estate, gift, or any other taxes
imposed upon or measured by Landlord's gross income or profits, unless the same
shall be imposed in lieu of real estate taxes or other ad valorem taxes), which
Landlord shall pay or become obligated to pay


<PAGE>   8

in connection with the Building, or any part thereof. Property Taxes shall also
include all fees and costs, including attorneys' fees, appraisals and
consultants' fees, incurred by Landlord in seeking to obtain a reassessment,
reduction of, or a limit on the increase in, any Property Taxes, but the total
of said fees and costs shall not exceed the amount of any reduction in Property
Taxes actually granted. If due to Landlord's gross negligence it fails to timely
pay any installment of Property Taxes, and as a direct consequence thereof the
taxing authority assesses a late fee or penalty, said late fee or penalty shall
not be included in Property Taxes. Property Taxes for any calendar year shall be
Property Taxes which are due for payment or paid in such year, rather than
Property Taxes which are assessed or become a lien during such year. Property
Taxes shall include any tax, assessment, levy, imposition or charge imposed upon
Landlord and measured by or based in whole or in part upon the Building or the
rents or other income from the Building, to the extent that such items would be
payable if the Building was the only property of Landlord subject to same and
the income received by Landlord from the Building was the only income of
Landlord. Property Taxes shall also include any personal property taxes imposed
upon the furniture, fixtures, machinery, equipment, apparatus, systems and
appurtenances of Landlord used in connection with the Building.

             4.1.3. Operating Expenses. The term "Operating Expenses" shall mean
all costs, fees, disbursements and expenses paid or incurred by or on behalf of
Landlord in the operation, ownership, maintenance, insurance, management,
replacement and repair of the Building (excluding Property Taxes) including
without limitation:

                  (i) Premiums for property, casualty, liability, earthquake,
Rent interruption or other types of insurance carried by Landlord to the extent
carried by other institutional owners and operators of first class office.

                  (ii) Salaries, wages, and other amounts paid or payable for
personnel including the Building manager, superintendent, operation and
maintenance staff, and other employees of Landlord involved in the maintenance
and operation of the Building, including contributions and premiums towards
fringe benefits, unemployment, disability and worker's compensation insurance,
pension plan contributions and similar premiums and contributions and the total
charges of any independent contractors or property managers engaged in the
operation, repair, care, maintenance and cleaning of any portion of the
Building.

                  (iii) Cleaning expenses, including without limitation
janitorial services, window cleaning, and garbage and refuse plants.

                  (iv) Landscape expenses, including without limitation
irrigation, trimming, mowing, fertilizing, seeding, and replacing plants.

                  (v) Heating, ventilating, air conditioning and steam/utilities
expenses, including fuel, gas, electricity, water, sewer, telephone, and other
services.

                  (vi) Maintaining operating, repairing and replacing components
of equipment or machinery, including without limitation heating, refrigeration,
ventilation, electrical, plumbing, mechanical, elevator, escalator, sprinklers,
fire/life safety, security and energy management system, including service
contractors, maintenance contracts, supplies and parts.

                  (vii) Other items of repair or maintenance of elements of the
Building.

                  (viii) The costs of policing, security and supervision of the
Building.

                  (ix) Fair market rental and other costs with respect to the
management office for the Building.

                  (x) The cost of the rental of any machinery or equipment and
the cost of supplies used in the maintenance and operation of the Building.

                  (xi) Audit fees and the cost of accounting services incurred
in the preparation of statements referred to in this Lease and financial
statements, and in the computation of the rents and charges payable by tenants
of the Building.

<PAGE>   9

                  (xii) Capital expenditures (a) made primarily to reduce
Operating Expenses or to comply with any laws or other governmental requirements
applicable to the Building, or (b) for replacements (as opposed to additions or
new improvements) of items located in the common areas of the Building, required
to keep such areas in good condition; provided all such permitted capital
expenditures (together with reasonable financing charges) shall be amortized for
purposes of this Lease over the shorter of (x) their useful lives, (y) the
period during which the reasonably estimated savings in Operating Expenses
equals the expenditures, or (z) three (3) years.

                  (xiii) Legal fees and expenses.

                  (xiv) Payments under any easement, operating agreement,
declaration, restrictive covenant, or instrument pertaining to the sharing of
costs in any planned development.

                  (xv) A fee for the administration and management of the
Building as reasonably determined by Landlord from time to time.

             4.1.4. Exclusions from Operating Expenses. Operating Expenses shall
not include costs of alteration of the premises of tenants of the Building,
depreciation charges, interest and principal payments on mortgages, ground
rental payments, real estate brokerage and leasing commissions, expenses
incurred in enforcing obligations of tenants of the Building, salaries and other
compensation of executive officers of the managing agent of the Building senior
to the Building manager, costs of any special service provided to any one tenant
of the Building but not to tenants of the Building generally, and costs of
marketing or advertising the Building.

             4.1.5. Adjustment. If the Building does not have one hundred
percent (100%) occupancy during an entire calendar year, including the Base
Year, then the variable cost component of "Property Tax" and "Operating
Expenses" shall be equitably adjusted so that the total amount of Property Tax
and Operating Expenses equals the total amount which would have been paid or
incurred by Landlord had the Building been one hundred percent (100%) occupied
for the entire calendar year. In no event shall Landlord be entitled to receive
from Tenant and any other tenants in the Building an aggregate amount in excess
of actual Operating Expenses as a result of the foregoing provision.

        4.2 BASE RENT.

             4.2.1. Rent Adjustment. During the Lease Term, Tenant shall pay to
Landlord as rental for the Premises the Base Rent described in Section 1.8
above, subject to adjustment (herein called the "Rent Adjustment") as follows:
per the Base Rent schedule in Section 1.8 above.

             4.2.2. Tax and Operating Expense Adjustment. In addition to the
Rent Adjustment, during each calendar year subsequent to the Base Year, the Base
Rent shall be increased by (collectively, the "Tax and Operating Expense
Adjustment"): (i) Tenant's Percentage Share of the total dollar increase, if
any, in Property Taxes for such year over Property Taxes for the Base Year; and
(ii) Tenant's Percentage Share of the total dollar increase, if any, in
Operating Expenses paid or incurred by Landlord during such year over Operating
Expenses paid or incurred by Landlord during the Base Year. A decrease in
Property Taxes or Operating Expenses below the Base Year amounts shall not
decrease the amount of the Base Rent due hereunder or give rise to a credit in
favor of Tenant.

             4.2.3. Tax Exempt Tenant. If Tenant's Additional Rent as finally
determined for any calendar year exceeds the total payments made by Tenant on
account thereof, Tenant shall pay Landlord the deficiency within ten (10) days
of Tenant's receipt of Landlord's statement. If the total payments made by
Tenant on account thereof exceed Tenant's Additional Rent as finally determined
for such year, Tenant's excess payment shall be credited toward the rent next
due from Tenant under this Lease. For any partial calendar year at the beginning
or end of the Term, Additional Rent shall be prorated on the basis of a 365-day
year by computing Tenant's Share of the increases in Operating Costs and Taxes
for the entire year and then prorating such amount for the number of days during
such year included in the Term. Notwithstanding the termination of this Lease,
Landlord shall pay to Tenant or Tenant shall pay


<PAGE>   10

to Landlord, as the case may be, within ten (10) days after Tenant's receipt of
Landlord's final statement for the calendar year in which this Lease terminates,
the difference between Tenant's Additional Rent for that year, as finally
determined by Landlord, and the total amount previously paid by Tenant on
account thereof.

        If for any reason Base Taxes or Taxes for any year during the Term are
reduced, refunded or otherwise changed, Tenant's Additional Rent shall be
reduced, refunded or adjusted accordingly. If Taxes are temporarily reduced as a
result of space in the Building being leased to a tenant that is entitled to an
exemption from property taxes or other taxes, then for purposes of determining
Additional Rent for each year in which Taxes are reduced by any such exemption,
Taxes for such year shall be calculated on the basis of the amount the Taxes for
the year would have been in the absence of the exemption. The obligations of
Landlord to refund any overpayment of Additional Rent and of Tenant to pay any
Additional Rent not previously paid shall survive the expiration of the Term.
Notwithstanding anything to the contrary in this Lease, if there is at any time
a decrease in Taxes below the amount of the Taxes for the Base Year, then for
purposes of calculating Additional Rent for the year in which such decrease
occurs and all subsequent periods, Base Taxes shall be reduced to equal the
Taxes for the year in which the decrease occurs.

        4.3 ADJUSTMENT PROCEDURE; ESTIMATES. The Tax and Operating Expense
Adjustment shall be determined and paid as follows:

             4.3.1. Estimates. During each calendar year subsequent to the Base
Year, Landlord shall give Tenant written notice of its estimate of any increased
amounts payable under Section 4.2.2 for that calendar year. On or before the
first day of each calendar month during the calendar year, Tenant shall pay to
Landlord one-twelfth (1/12th) of such estimated amounts; provided, however,
that, not more often than quarterly, Landlord may, by written notice to Tenant,
revise its estimate for such year, and subsequent payments by Tenant for such
year shall be based upon such revised estimate.

             4.3.2. Landlord's Statement. Within one hundred twenty (120) days
after the close of each calendar year or as soon thereafter as is practicable,
Landlord shall deliver to Tenant a statement of that year's Property Taxes and
Operating Expenses, and the actual Tax and Operating Expense Adjustment to be
made pursuant to Section 4.2.2 for such calendar year, as determined by Landlord
(the "Landlord's Statement"). Such Landlord's Statement shall be binding upon
Tenant, except as specifically provided in Section 4.4 below. If the amount of
the actual Tax and Operating Expense Adjustment is more than the estimated
payments for such calendar year made by Tenant, Tenant shall pay the deficiency
to Landlord within five (5) days of receipt of Landlord's Statement. If the
amount of the actual Tax and Operating Expense Adjustment is less than the
estimated payments for such calendar year made by Tenant, any excess shall be
credited against Rent (as hereinafter defined) next payable by Tenant under this
Lease or, if the Lease Term has expired, any excess shall be paid to Tenant. No
delay in providing the Statement shall act as a waiver of Landlord's right to
increase in payment pursuant to the Tax and Operating Expense Adjustment.

             4.3.3. Termination. If this Lease shall terminate on a day other
than the end of a calendar year, the amount of the Tax and Operating Expense
Adjustment to be paid that is applicable to the calendar year in which such
termination occurs shall be prorated on the basis of the number of days from
January 1 of the calendar year to the termination date bears to 365. The
termination of this Lease shall not affect the obligations of Landlord and
Tenant pursuant to Section 4.3.2 to be performed after such termination.

        4.4 REVIEW OF LANDLORD'S STATEMENT. Provided that Tenant is not then in
default beyond any applicable cure period of its obligations to pay Base Rent,
additional rent described in Section 4.2.2 or any other payments required to be
made by it under this Lease, and provided further that Tenant strictly complies
with the provisions of this Section 4.4, Tenant shall have the right, once each
calendar year, to reasonably review supporting data for any portion of a
Landlord's Statement (provided, however, Tenant may not have an audit or review
right to all documentation relating to Building operations as this would far
exceed the relevant information necessary to properly document a pass-through
billing statement, but real estate tax statements, and information on utilities,
repairs, maintenance and insurance will be available), in accordance with the
following procedure:


<PAGE>   11

             4.4.1. Notice. Tenant shall, within ten (10) business days after
any such Landlord's Statement is delivered, deliver a written notice to Landlord
specifying the portions of the Landlord's Statement that are claimed to be
incorrect, and Tenant shall simultaneously pay to Landlord all amounts due from
Tenant to Landlord as specified in the Landlord's Statement, Except as expressly
set forth below, in no event shall Tenant be entitled to withhold, deduct, or
offset any monetary obligation of Tenant to Landlord under the Lease (including,
without limitation, Tenant's obligation to make all payments of Base Rent and
all payments of Tenant's Tax and Operating Expense Adjustment) pending the
completion of and regardless of the results of any review of records under this
Section 4.4. The right of Tenant under this Section 4.4 may only be exercised
once for any Landlord's Statement, and if Tenant fails to meet any of the above
conditions as a prerequisite to the exercise of such right, the right of Tenant
under this Section 4.4 for a particular Landlord's Statement shall be deemed
waived.

             4.4.2. Records. Tenant acknowledges that Landlord maintains its
records for the Building at Landlord's manager's corporate offices presently
located at the address set forth in Section 1.12 and Tenant agrees that any
review of records under this Section 4.4 shall be at the sole expense of Tenant
and shall be conducted by an independent firm of certified public accountants of
national standing. Tenant acknowledges and agrees that any records reviewed
under this Section 4.4 constitute confidential information of Landlord, which
shall not be disclosed to anyone other than the accountants performing the
review and the principals of Tenant who receive the results of the review. The
disclosure of such information to any other person, whether or not caused by the
conduct of Tenant, shall constitute a material breach of this Lease.

             4.4.3. Landlord's Review; Reconciliation. Any errors disclosed by
the review shall be promptly corrected by Landlord, provided, however, that if
Landlord disagrees with any such claimed errors, Landlord shall have the right
to cause another review to be made by an independent form of certified public
accountants of national standing. In the event of a disagreement between the two
accounting firms, the review that discloses the least amount of deviation from
the Landlord's Statement shall be deemed to be correct. In the event that the
results of the review of records (taking into account, if applicable, the
results of any additional review caused by Landlord) reveal that Tenant has
overpaid obligations for a preceding period, the amount of such overpayment
shall be credited against Tenant's subsequent installment obligations to pay the
estimated Tax and Operating Expense Adjustment. In the event that such results
show that Tenant has underpaid its obligations for a preceding period, Tenant
shall be liable for Landlord's actual accounting fees, and the amount of such
underpayment shall be paid by Tenant to Landlord with the next succeeding
installment obligation of estimated Tax and Operating Expense Adjustment.

        4.5 PAYMENT. Concurrently with the execution hereof, Tenant shall pay
Landlord Base Rent for the first calendar month of the Lease Term. Thereafter
the Base Rent described in Section 1.8, as adjusted in accordance with Section
4.2, shall be payable in advance on the first day of each calendar month. If the
Commencement Date is other than the first day of a calendar month, the prepaid
Base Rent for such partial month shall be prorated in the proportion that the
number of days this Lease is in effect during such partial month bears to the
total number of days in the calendar month. All Rent, and all other amounts
payable to Landlord by Tenant pursuant to the provisions of this Lease, shall be
paid to Landlord, without notice, demand, abatement, deduction or offset, in
lawful money of the United States at Landlord's office in the Building or to
such other person or at such other place as Landlord may designate from time to
time by written notice given to Tenant. No payment by Tenant or receipt by
Landlord of a lesser amount than the correct Rent due hereunder shall be deemed
to be other than a payment on account; nor shall any endorsement or statement on
any check or any letter accompanying any check or payment be deemed to effect or
evidence an accord and satisfaction; and Landlord may accept such check or
payment without prejudice to Landlord's right to recover the balance or pursue
any other remedy in this Lease or at law or in equity provided.

        4.6 LATE CHARGE; INTEREST. Tenant acknowledges that the late payment of
Base Rent or any other amounts payable by Tenant to Landlord hereunder (all of
which shall constitute additional rental to the same extent as Base Rent) will
cause Landlord to incur administrative costs and other damages, the exact amount
of which would be impracticable or extremely difficult to ascertain. Landlord
and Tenant agree that if Landlord does not receive any such payment on or before
five (5) days after the date the payment is due, Tenant shall pay to Landlord,
as additional rent, (a) a late charge equal to five percent (5%) of the overdue
amount to


<PAGE>   12

cover such additional administrative costs; and (b) interest on the delinquent
amounts at the lesser of the maximum rate permitted. by law (if any) or twelve
percent (12%) per annum from the date due to the date paid.

        4.7 ADDITIONAL RENT. For purposes of this Lease, all amounts payable by
Tenant to Landlord pursuant to this Lease, whether or not denominated as such,
shall constitute additional rental hereunder. Such additional rental, together
with the Base Rent, Rent Adjustment, and Tax and Operating Expense Adjustment,
shall sometimes be referred to in this Lease as "Rent".

        4.8 ADDITIONAL TAXES. Notwithstanding anything in Section 4.1.2 to the
contrary, Tenant shall reimburse Landlord upon demand for any and all taxes
payable by or imposed upon Landlord upon or with respect to: any fixtures or
personal property located in the Premises; any leasehold improvements made in or
to the Premises by or for Tenant; the Rent payable hereunder, including, without
limitation, any gross receipts tax, license fee or excise tax levied by any
governmental authority; the possession, leasing, operation, management,
maintenance, alteration, repair, use or occupancy of any portion of the Premises
(including without limitation any applicable possessory interest taxes); or this
transaction or any document to which Tenant is a party creating or transferring
an interest or an estate in the Premises.

                          ARTICLE V - SECURITY DEPOSIT

        Upon the execution of this Lease, Tenant shall deposit with Landlord the
Security Deposit described in Section 1.10 above. The Security Deposit is made
by Tenant to secure the faithful performance of all the terms, covenants and
conditions of this Lease to be performed by Tenant. If Tenant shall default with
respect to any covenant or provision hereof, Landlord may use, apply or retain
all or any portion of the Security Deposit to cure such default or to compensate
Landlord for any loss or damage which Landlord may suffer thereby. If Landlord
so uses or applies all or any portion of the Security Deposit, Tenant shall
immediately upon written demand deposit cash with Landlord in an amount
sufficient to restore the Security Deposit to the full amount hereinabove
stated. Landlord shall not be required to keep the Security Deposit separate
from its general accounts and Tenant shall not be entitled to interest on the
Security Deposit. Within thirty (30) days after the expiration of the Lease Term
and the vacation of the Premises by Tenant, the Security Deposit, or such part
as has not been applied to cure any default of Tenant, shall be returned to
Tenant.

                          ARTICLE VI - USE OF PREMISES

        6.1 TENANT'S PERMITTED USE. Tenant shall use the Premises only for
Tenant's Permitted Use as set forth in Section 1.11 above and shall not use or
permit the Premises to be used for any other purpose. Tenant shall, at its sole
cost and expense, obtain all governmental licenses and permits required to allow
Tenant to conduct Tenant's Permitted Use. Landlord disclaims any warranty that
the Premises are suitable for Tenant's use and Tenant acknowledges that it has
had a full opportunity to make its own determination in this regard.

        6.2 COMPLIANCE WITH LAWS AND OTHER REQUIREMENTS.

             6.2.1. Applicable Law. Tenant shall cause the Premises to comply in
all material respects with all laws, ordinances, regulations and directives of
any governmental authority having jurisdiction including, without limitation,
any certificate of occupancy and any law, ordinance, regulation, covenant,
condition or restriction affecting the Building or the Premises which in the
future may become applicable to the Premises (collectively "Applicable Law").

             6.2.2. No Violation. Tenant shall not use the Premises, or permit
the Premises to be used, in any manner which: (a) violates any Applicable Law;
(b) causes or is reasonably likely to cause damage to the Building or the
Premises; (c) violates a requirement or condition of any fire and extended
insurance policy covering the Building and/or the Premises, or increases the
cost of such policy; (d) constitutes or is reasonably likely to constitute a
nuisance, annoyance or inconvenience to other tenants or occupants of the
Building or its equipment, facilities or systems; (e) interferes with, or is
reasonably likely to interfere with, the transmission or reception of microwave,
television, radio, telephone or other communication


<PAGE>   13

signals by antennae or other facilities located in the Building; or (f) violates
the Rules and Regulations described in Article XVIII.

             6.3 HAZARDOUS MATERIALS.

                  6.3.1. Prohibition. No Hazardous Materials (as defined
herein), shall be Handled (as also deemed herein), upon, about, above or beneath
the Premises or any portion of the Building by or on behalf of Tenant, its
subtenants or its assignees, or their respective contractors, clients, officers,
directors, employees, agents, or invitees. Any such Hazardous Materials so
Handled shall be known as Tenant's Hazardous Materials. Notwithstanding the
foregoing, normal quantities of Tenant's Hazardous Materials customarily used in
the conduct of general administrative and executive office activities (e.g.,
copier fluids and cleaning supplies) may be Handled at the Premises without
Landlord's prior written consent. Tenant's Hazardous Materials shall be Handled
at all times in compliance with the manufacturer's instructions therefor and all
applicable Environmental Law (as defined herein).

                  6.3.2. Remediation. Notwithstanding the obligation of Tenant
to indemnify Landlord pursuant to this Lease, Tenant shall, at its sole cost and
expense, promptly take all actions required by any Regulatory Authority (as
defined herein), or necessary for Landlord to make full economic use of the
Premises or any portion of the Building, which requirements or necessity arises
from the Handling of Tenant's Hazardous Materials upon, about, above or beneath
the Premises or any portion of the Building. Such actions shall include, but not
be limited to, the investigation of the environmental condition of the Premises
or any portion of the Building, the preparation of any feasibility studies or
reports and the performance of any cleanup, remedial, removal or restoration
work. Tenant shall take all actions necessary to restore the Premises or any
portion of the Building to the condition existing prior to the introduction of
Tenant's Hazardous Materials, notwithstanding any less stringent standards or
remediation allowable under applicable Environmental Laws. Tenant shall
nevertheless obtain Landlord's written approval prior to undertaking any actions
required by this Section, which approval shall not be unreasonably withheld so
long as such actions would not potentially have a material adverse long-term or
short-term effect on the Premises or any portion of the Building.

                  6.3.3. Additional Documents. Tenant agrees to execute
affidavits, representations, and the like from time to time at Landlord's
request stating Tenant's best knowledge and belief regarding the presence of
Hazardous Materials on the Premises.

                  6.3.4. Environmental Laws. As used herein, "Environmental
Laws" means and includes all now and hereafter existing statutes, laws,
ordinances, codes, regulations, rules, rulings, orders, decrees, directives,
policies and requirements by any Regulatory Authority regulating, relating to,
or imposing liability or standards of conduct concerning public health and
safety or the environment.

                  6.3.5. Hazardous Materials. As used herein, "Hazardous
Materials" means: (a) any material or substance: (i) which is defined or becomes
defined as a "hazardous substance", "hazardous waste," "infectious waste,"
"chemical mixture or substance," or "air pollutant" under Environmental Laws;
(ii) containing petroleum, crude oil or any fraction thereof; (iii) containing
polychlorinated biphenyls (PCB's); (iv) containing asbestos; (v) which is
radioactive; or (vi) which is infectious; or (b) any other material or substance
displaying toxic, reactive, ignitable or corrosive characteristics, as all such
terms are used in their broadest sense, and are defined, or become defined by
environmental laws; or (c) materials which cause a nuisance upon or waste to the
Premises or any portion of the Building.

                  6.3.6. Handle. As used herein, "Handle," "handle," "Handled,"
"handled," "Handling," or "handling" shall mean any installation, handling,
generation, storage, treatment, use, disposal, discharge, release, manufacture,
refinement, presence, migration, emission, abatement, removal, transportation,
or any other activity of any type in connection with or involving Hazardous
Materials.

                  6.3.7. Regulatory Authority. As used herein, "Regulatory
Authority" shall mean any federal, state or local governmental agency,
commission, board or political subdivision.


<PAGE>   14

                      ARTICLE VII - UTILITIES AND SERVICES

        7.1 BUILDING SERVICES. As long as Tenant is not in monetary default
under this Lease, Landlord agrees to furnish or cause to be furnished to the
Premises the following utilities and services, subject to the conditions and
standards set forth herein:

             7.1.1. Elevator Service. Non-attended automatic elevator service
(if the Building has such equipment serving the Premises), in common with
Landlord and other tenants and occupants and their agents and invitees.

             7.1.2. HVAC. During Business Hours, such air conditioning, heating
and ventilation as, in Landlord's reasonable judgment, are required for the
comfortable use and occupancy of the Premises; provided, however, that if Tenant
shall require heating, ventilation or air conditioning in excess of that which
Landlord shall be required to provide hereunder, Landlord may provide such
additional heating, ventilation or air conditioning at such rates and upon such
additional conditions as shall be determined by Landlord from time to time.

             7.1.3. Water. Water for drinking and if rest rooms are within the
Premises, rest room purposes.

             7.1.4. Janitorial and Cleaning. Reasonable janitorial and cleaning
services, provided that the Premises are used exclusively for office purposes
and are kept reasonably in order by Tenant. If the Premises are not used
exclusively as offices, Landlord, at Landlord's sole discretion, may require
that the Premises be kept clean and in order by Tenant, at Tenant's expense, to
the satisfaction of Landlord and by persons approved by Landlord; and, in all
events, Tenant shall pay to Landlord the cost of removal of Tenant's refuse and
rubbish, to the extent that the same exceeds the refuse and rubbish attendant to
normal office usage.

             7.1.5. Electricity. At all reasonable times, electric current as
required for building standard lighting and fractional horsepower office
machines; provided, however, that: (i) without Landlord's consent, Tenant shall
not install, or permit the installation, in the Premises of any computers, word
processors, electronic data processing equipment or other type of equipment or
machines which will increase Tenant's use of electric current in excess of that
which Landlord is obligated to provide hereunder (provided, however, that the
foregoing shall not preclude the use of personal computers or similar office
equipment); (ii) if Tenant shall require electric current which may disrupt the
provision of electrical service to other tenants, Landlord may refuse to grant
its consent or may condition its consent upon Tenant's payment of the cost of
installing and providing any additional facilities required to furnish such
excess power to the Premises and upon the installation in the Premises of
electric current meters to measure the amount of electric current consumed, in
which latter event Tenant shall pay for the cost of such meter(s) and the cost
of installation, and repair thereof, as well as for all excess electric current
consumed at the rates charged by the applicable local public utility, plus a
reasonable amount to cover the additional expenses incurred by Landlord in
keeping account of the electric current so consumed; and (iii) if Tenant's
increased electrical requirements will materially affect the temperature level
in the Premises or the Building, Landlord's consent may be conditioned upon
Tenant's requirement to pay such amounts as will be incurred by Landlord to
install and operate any machinery or equipment necessary to restore the
temperature level to that otherwise required to be provided by Landlord,
including but not limited to the cost of modifications to the air conditioning
system. Landlord shall not, in any ways be liable or responsible to Tenant for
any loss or damage or expense which Tenant may incur or sustain if, for any
reasons beyond Landlord's reasonable control, either the quantity or character
of electric service is changed or is no longer available or suitable for
Tenant's requirements. Tenant covenants that at all times its use of electric
current shall never exceed the capacity of the feeders, risers or electrical
installations of the Building. If submetering of electricity in the Building
will not be permitted under future laws or regulations, the Rent will then be
equitably and periodically adjusted to include an additional payment to Landlord
reflecting the cost to Landlord for furnishing electricity to Tenant in the
Premises.

             7.1.6. Payments. Any amounts which Tenant is required to pay to
Landlord pursuant to this Section 7. l shall be payable upon demand by Landlord
and shall constitute additional rent.


<PAGE>   15

        7.2 INTERRUPTION OF SERVICE. Landlord shall not be liable for any
failure to furnish, stoppage of, or interruption in furnishing any of the
services or utilities described in Section 7.1, when such failure is caused by
accident, breakage, repairs, strikes, lockouts, labor disputes, labor
disturbances, governmental regulation, civil disturbances, acts of war,
moratorium or other governmental action, or any other cause beyond Landlord's
reasonable control, and, in such event, Tenant shall not be entitled to any
damages nor shall any failure or interruption abate or suspend Tenant's
obligation to pay Rent, Base Rent and additional rent required under this Lease
or constitute or be construed as a constructive or other eviction of Tenant.
Further, in the event any governmental authority or public utility promulgates
or revises any law, ordinance, rule or regulation, or issues mandatory controls
or voluntary controls relating to the use or conservation of energy, water, gas,
light or electricity, the reduction of automobile or other emissions, or the
provision of any other utility or service, Landlord may take any reasonably
appropriate action to comply with such law, ordinance, rule, regulation,
mandatory control or voluntary guideline and Tenant's obligations hereunder
shall not be affected by any such action of Landlord. The parties acknowledge
that safety and security devices, services and programs provided by Landlord, if
any, while intended to deter crime and ensure safety, may not in given instances
prevent theft or other criminal acts, or ensure safety of persons or property.
The risk that any safety or security device, service or program may not be
effective, or may malfunction, or be circumvented by a criminal, is assumed by
Tenant with respect to Tenant's property and interests, and Tenant shall obtain
insurance coverage to the extent Tenant desires protection against such criminal
acts and other losses, as further described in this Lease. Tenant agrees to
cooperate in any reasonable safety or security program developed by Landlord or
required by Law.

        7.3 UTILITY DEREGULATION.

             7.3.1. Landlord Controls Selection. Landlord has advised Tenant
that presently Pacific Gas & Electric ("Electric Service Provider") is the
utility company selected by Landlord to provide electricity service for 44
Montgomery Skeet. Notwithstanding the foregoing, if permitted by law, Landlord
shall have the right at any time and from time to time during the Lease Term to
either contract for service from a different company or companies providing
electricity service (each such company shall hereinafter be referred to as an
"Alternate Service Provider") or continue to contract for service from the
Electric Service Provider.

             7.3.2. Tenant Shall Give Landlord Access. Tenant shall cooperate
with Landlord, the Electric Service Provider, and any Alternate Service Provider
at all times and, as reasonably necessary, shall allow Landlord, Electric
Service Provider, and any Alternate Service Provider reasonable access to 44
Montgomery Street's electric lines, feeders, risers, wiring and any other
machinery within the Premises.

                     ARTICLE VIII - MAINTENANCE AND REPAIRS

        8.1 LANDLORD'S OBLIGATIONS. Except as expressly provided in Sections 8.2
and 8.3 below, Landlord shall maintain the Building in reasonable order and
repair throughout the Lease Term; provided, however, that Landlord shall not be
liable for any failure to make any repairs or to perform any maintenance unless
such failure shall persist for an unreasonable time after written notice of the
need for such repairs or maintenance is given to Landlord by Tenant. Except as
provided in Article XI, there shall be no abatement of Rent, nor shall there be
any liability of Landlord, by reason of any injury or inconvenience to, or
interference with, Tenant's business or operations arising from the making of,
or failure to make, any maintenance or repairs in or to any portion of the
Building.

        8.2 TENANT'S OBLIGATIONS. During the Lease Term, Tenant shall, at its
sole cost and expense, maintain the Premises in good order and repair
(including, without limitation, the carpet, wall-covering, doors, plumbing and
other fixtures, equipment, alterations and improvements, whether installed by
Landlord or Tenant). Further, Tenant shall be responsible for, and upon demand
by Landlord shall promptly reimburse Landlord for, any damage to any portion of
the Building or the Premises caused by (a) Tenant's activities in the Building
or the Premises; (b) the performance or existence of any alterations, additions
or improvements made by Tenant in or to the Premises; (c) the installation, use,
operation or movement of Tenant's property in or about the Building or the
Premises; or (d) any act or omission by Tenant or its officers, partners,
employees, agents, contractors or invitees.


<PAGE>   16

        8.3 LANDLORD'S RIGHTS. Landlord and its contractors shall have the
right, at all reasonable times and upon prior written, oral or telephonic notice
to Tenant at the Premises, other than in the case of any emergency in which case
no notice shall be required, to enter upon the Premises to make any repairs to
the Premises or the Building reasonably or deemed reasonably necessary by
Landlord and to erect such equipment, including scaffolding, as is reasonably
necessary to effect such repairs.

              ARTICLE IX - ALTERATIONS, ADDITIONS AND IMPROVEMENTS

        9.1 LANDLORD'S CONSENT; CONDITIONS. Tenant shall not make or permit to
be made any alterations, additions, or improvements in or to the Premises
("Alterations") without the prior written consent of Landlord, which consent,
with respect to non-structural alterations, shall not be unreasonably withheld,
and which consent with respect to any alterations which may affect the
structural or safety components of the Building, may be given or withheld in
Landlord's sole and absolute discretion. Landlord may impose as a condition to
making any Alterations such requirements as Landlord in its sole discretion
deems necessary or desirable including without limitation: Tenant's submission
to Landlord, for Landlord's prior written approval, of all plans and
specifications relating to the Alterations; Landlord's prior written approval of
the time or times when the Alterations are to be performed; Landlord's prior
written approval of the contractors and subcontractors performing work in
connection with the Alterations; employment of union contractors and
subcontractors who shall not cause labor disharmony; Tenant's receipt of all
necessary permits and approvals from all governmental authorities having
jurisdiction over the Premises prior to the construction of the Alterations;
Tenant's delivery to Landlord of such bonds and insurance as Landlord shall
reasonably require; and Tenant's payment to Landlord of all costs and expenses
incurred by Landlord because of Tenant's Alterations, including but not limited
to costs incurred in reviewing the plans and specifications for, and the
progress of, the Alterations. Tenant is required to provide Landlord written
notice of whether the Alterations include the Handling of any Hazardous
Materials and whether these materials are of a customary and typical nature for
industry practices. Upon completion of the Alterations, Tenant shall provide
Landlord with copies of as-built plans. Neither the approval by Landlord of
plans and specifications relating to any Alterations nor Landlord's supervision
or monitoring of any Alterations shall constitute any warranty by Landlord to
Tenant of the adequacy of the design for Tenant's intended use or the proper
performance of the Alterations.

        9.2 PERFORMANCE OF ALTERATIONS WORK. All work relating to the
Alterations shall be performed in compliance with the plans and specifications
approved by Landlord, all applicable laws, ordinances, rules, regulations and
directives of all governmental authorities having jurisdiction (including
without limitation Title 24 of the California Administrative Code) and the
requirements of all carriers of insurance on the Premises and the Building, the
Board of Underwriters, Fire Rating Bureau, or similar organization. All work
shall be performed in a diligent, first class manner and so as not to
unreasonably interfere with any other tenants or occupants of the Building. All
costs incurred by Landlord relating to the Alterations shall be payable to
Landlord by Tenant as additional rent upon demand. No asbestos-containing
materials shall be used or incorporated in the Alterations. No lead-containing
surfacing material, solder, or other construction materials or fixtures where
the presence of lead might create a condition of exposure not in compliance with
Environmental Laws shall be incorporated in the Alterations.

        9.3 LIENS. Tenant shall pay when due all costs for work performed and
materials supplied to the Premises. Tenant shall keep Landlord, the Premises and
the Building free from all liens, stop notices and violation notices relating to
the Alterations or any other work performed for, materials furnished to or
obligations incurred by or for Tenant and Tenant shall protect, indemnify, hold
harmless and defend Landlord, the Premises and the Building of and from any and
all loss, cost, damage, liability and expense, including attorneys' fees,
arising out of or related to any such liens or notices. Further, Tenant shall
give Landlord not less than seven (7) business days prior written notice before
commencing any Alterations in or about the Premises to permit Landlord to post
appropriate notices of non-responsibility. Tenant shall also secure, prior to
commencing any Alterations, at Tenant's sole expense, a completion and lien
indemnity bond satisfactory to Landlord for such work. During the progress of
such work, Tenant shall, upon Landlord's request, furnish Landlord with sworn
contractor's statements and lien waivers covering all work theretofore
performed. Tenant shall satisfy or otherwise discharge all liens, stop notices
or other claims or encumbrances within ten (10) days after


<PAGE>   17

Landlord notifies Tenant in writing that any such lien, stop notice, claim or
encumbrance has been filed. If Tenant fails to pay and remove such lien, claim
or encumbrance within such ten (10) days, Landlord, at its election, may pay and
satisfy the same and in such event the sums so paid by Landlord, with interest
from the date of payment at the rate set forth in this Lease for amounts owed
Landlord by Tenant shall be deemed to be additional rent due and payable by
Tenant at once without notice or demand.

        9.4 LEASE TERMINATION. Except as provided herein, upon expiration or
earlier termination of this Lease Tenant shall surrender the Premises to
Landlord in the same condition as existed on the date Tenant first occupied the
Premises (whether pursuant to this Lease or an earlier lease), subject to
reasonable wear and tear. All Alterations shall become a part of the Premises
and shall become the property of Landlord upon the expiration or earlier
termination of this Lease, unless Landlord shall, by written notice given to
Tenant, require Tenant to remove some or all of Tenant's Alterations, in which
event Tenant shall promptly remove the designated Alterations and shall promptly
repair any resulting damage, all at Tenant's sole expense. All business and
trade fixtures, machinery and equipment, furniture, movable partitions and items
of personal property owned by Tenant or installed by Tenant at its expense in
the Premises shall be and remain the property of Tenant, upon the expiration or
earlier termination of this Lease, Tenant shall, at its sole expense, remove all
such items and repair any damage to the Premises or the Building caused by such
removal. If Tenant fails to remove any such items or repair such damage promptly
after the expiration or earlier termination of the Lease, Landlord may, but need
not, do so with no liability to Tenant, and Tenant shall pay Landlord the cost
thereof upon demand. Notwithstanding the foregoing to the contrary, in the event
that Landlord gives its consent, pursuant to the provisions of this Article IX,
to allow Tenant to make an Alteration in the Premises, Landlord agrees, upon
Tenant's written request, to notify Tenant in writing at the time of the giving
of such consent whether Landlord will require Tenant, at Tenant's cost, to
remove such Alteration at the end of the Lease Term.

                    ARTICLE X - INDEMNIFICATION AND INSURANCE

        10.1 INDEMNIFICATION.

             10.1.1.Tenant. Tenant agrees to protect, indemnify, hold harmless
and defend Landlord and any Mortgagee, as defined herein, and each of their
respective partners, directors, officers, agents and employees, successors and
assigns (except to the extent the losses described below are caused by the gross
negligence or intentional misconduct of Landlord, its agents and employees),
from and against:

                  (i) any and all loss, cost, damage, liability or expense as
incurred (including but not limited to reasonable attorneys' fees and legal
costs) arising out of or related to any claim, suit or judgment brought by or in
favor of any person or persons for damage, loss or expense due to, but not
limited to, bodily injury, including death or property damage sustained by such
person or persons which arises out of, is occupied by or is in any way
attributable to the use or occupancy of the Premises or any portion of the
Building by Tenant or the acts or omissions of Tenant or its agents, employees,
contractors, clients, invitees or subtenants except that caused by the sole
active negligence or willful misconduct of Landlord or its agents or employees
Such loss or damage shall include, but not be limited to, any injury or damage
to, or death of, Landlord's employees or agents or damage to the Premises or any
portion of the Building.

                  (ii) any and all environmental damages which arise from: (a)
the Handling of any Tenants Hazardous Materials, as defined in Section 6.3 or
(b) the breach of any of the provisions of this Lease. For the purpose of this
Lease, "environmental damages" shall mean (x) all claims, judgments, damages,
penalties, fines, costs, liabilities, and losses (including without limitation,
diminution in the value of the Premises or any portion of the Building, damages
for the loss of or restriction on use of rentable or usable space or of any
amenity of the Premises or any portion of the Building, and from any adverse
impact of Landlord's marketing of space); (y) all reasonable sums paid for
settlement of claims, attorneys' fees, consultants' fees and experts' fees; and
(z) all costs incurred by Landlord in connection with investigation or
remediation relating to the Handling of Tenant's Hazardous Materials, whether or
not required by Environmental Laws, necessary for Landlord to make full economic
use of the Premises or any portion of the Building, or otherwise required under
this Lease. To the extent that Landlord is held strictly liable by a court or
other governmental agency of


<PAGE>   18

competent jurisdiction under any Environmental Laws, Tenant's obligation to
Landlord and the other indemnities under the foregoing indemnification shall
likewise be without regard to fault on Tenant's part with respect to the
violation of any Environmental Law which results in liability to the indemnitee.
Tenant's obligations and liabilities pursuant to this Section 10.1 shall survive
the expiration or earlier termination of this Lease.

             10.1.2.Landlord. Landlord agrees to protect, indemnify, hold
harmless and defend Tenant from and against any and all loss, cost, damage,
liability or expense, including reasonable attorneys' fees, with respect to any
claim of damage or injury to persons or property at the Premises, caused by the
gross negligence or intentional misconduct of Landlord or its authorized agents
or employees.

             10.1.3.No Limitation. Notwithstanding anything to the contrary
contained herein, nothing shall be interpreted or used to (a) in any way affect,
limit, reduce or abrogate any insurance coverage provided by any insurers to
either Tenant or Landlord, or (b) infer or imply that Tenant is a partner, joint
venturer, agent, employee, or otherwise acting by or at the direction of
Landlord.

        10.2 PROPERTY INSURANCE.

             10.2.1.Tenant All-Risk. At all times during the Lease Term, Tenant
shall procure and maintain, at its sole expense, "all-risk" property insurance,
for damage or other loss caused by fire or other casualty or cause including,
but not limited to, vandalism and malicious mischief, theft, water damage of any
type, including sprinkler leakage, bursting of pipes, and explosion, in an
amount not less than one hundred percent (100%) of the replacement cost covering
(a) all Alterations made by or for Tenant in the Premises; and (b) Tenant's
trade fixtures, equipment and other personal property from time to time situated
in the Premises. The proceeds of such insurance shall be used for the repair or/
replacement of the property so insured, except that if not so applied or if this
Lease is terminated following a casualty, the proceeds applicable to the
leasehold improvements shall be paid to Landlord and the proceeds applicable to
Tenant's personal property shall be paid to Tenant.

             10.2.2.Tenant Business Interruption. At all times during the Lease
Term, Tenant shall procure and maintain business interruption insurance in such
amount as will reimburse Tenant for direct or indirect loss of earnings
attributable to all perils insured against in Section 10.2.1.

             10.2.3.Landlord All-Risk. Landlord shall, at all times during the
Lease Term, procure and maintain "all-risk" property insurance in the amount not
less than ninety percent (90%) of the insurable replacement cost covering the
Building in which the Premises are located and such other insurance as may be
required by a Mortgagee or otherwise desired by Landlord.

        10.3 LIABILITY INSURANCE.

             10.3.1.Tenant. At all times during the Lease Term, Tenant shall
procure and maintain, at its sole expense, commercial general liability
insurance applying to the use and occupancy of the Premises and the business
operated by Tenant. Such insurance shall have a minimum combined single limit of
liability of at least Two Million Dollars ($2,000,000) per occurrence and a
general aggregate limit of at least Two Million Dollars ($2,000,000). All such
policies shall be written to apply to all bodily injury, property damage, and
personal injury losses, and shall be endorsed to include Landlord and its
agents, beneficiaries, partners, employees, and any deed of trust holder or
mortgagee of Landlord or any ground lessor as additional insureds. Such
liability insurance shall be written as primary policies, not excess or
contributing with or secondary to any other insurance as may be available to the
additional insureds.

             10.3.2. Alcohol. Prior to the sale, storage, use or giving away of
alcoholic beverages on or from the Premises by Tenant or another person, Tenant,
at its own expense, shall obtain a policy or policies of insurance issued by a
responsible insurance company and in a form acceptable to Landlord saving
harmless and protecting Landlord and the Premises against any and all damages,
claims, liens, judgments, expenses and costs, including actual attorneys' fees,
arising under any present or future law, statute, or ordinance of the State of
California or other


<PAGE>   19

governmental authority having jurisdiction of the Premises, by reason of any
storage, sale, use or giving away of alcoholic beverages on or from the
Premises. Such policy or policies of insurance shall have a minimum combined
single limit of One Million Dollars ($1,000,000) per occurrence and shall apply
to bodily injury, fatal or nonfatal; injury to means of support; and injury to
property of any person. Such policy or policies of insurance shall name Landlord
and its agents, beneficiaries, partners, employees and any mortgagee of Landlord
or any ground lessor of Landlord as additional insureds.

             10.3.3.Estimates. Landlord shall, at all during the Lease Term,
procure and maintain commercial general liability insurance for the Building in
which the Premises are located. Such insurance shall have minimum combined
single limit of liability of at least Two Million Dollars ($2,000,000) per
occurrence, and a general aggregate limit of at least Two Million Dollars
($2,000,000).

        10.4 WORKERS' COMPENSATION INSURANCE. At all times during the Lease
Term, Tenant shall procure and maintain Workers' Compensation Insurance in
accordance with the laws of the State of California, and Employer's Liability
insurance with a limit not less than One Million Dollars ($1,000,000) Bodily
Injury Each Accident; One Million Dollars ($1,000,000) Bodily Injury By Disease
- Each Person; -- and One Million Dollars ($ 1,000,000) Bodily Injury to Disease
- Policy Limit.

        10.5 POLICY REQUIREMENTS. All insurance required to be maintained by
Tenant shall be issued by insurance companies authorized to do insurance
business in the State of California and rated not less than A-VIII in Best's
Insurance Guide. A certificate of insurance (or, at Landlord's option, copies of
the applicable policies) evidencing the insurance required under this Article X
shall be delivered to Landlord not less than thirty (30) days prior to the
Commencement Date. No such policy shall be subject to cancellation or
modification without thirty (30) days prior written notice to Landlord and to
any deed of trust holder, mortgagee or ground lessor designated by Landlord to
Tenant. Tenant shall furnish Landlord with a replacement certificate with
respect to any insurance not less than thirty (30) days prior to the expiration
of the current policy. Tenant shall have the right to provide the insurance
required by this Article X pursuant to blanket policies, but only if such
blanket policies expressly provide coverage to the Premises and Landlord as
required by this Lease pursuant to a per-location endorsement.

        10.6 WAIVER OF SUBROGATION. Each party hereby waives any right of
recovery against the other for injury or loss due to hazards covered by
insurance or required to be covered, to the extent of the injury or loss covered
thereby. Any policy of insurance to be provided by Tenant or Landlord pursuant
to this Article X shall contain a clause denying the applicable insurer any
right of subrogation against the other party.

        10.7 FAILURE TO INSURE. If Tenant fails to maintain any insurance which
Tenant is required to maintain pursuant to this Article X, Tenant shall be
liable to Landlord for any loss or cost resulting from such failure to maintain.
Tenant may not self-insure against any risks required to be covered by insurance
without Landlord's prior written consent, which consent may be given or withheld
in Landlord's sole and absolute discretion.

                       ARTICLE XI - DAMAGE OR DESTRUCTION

        11.1 TOTAL DESTRUCTION. Except as provided in Section 11.3 below, this
Lease shall, at Landlord's election, terminate if the Building is totally
destroyed.

        11.2 PARTIAL DESTRUCTION OF PREMISES. If the Premises are damaged by any
casualty and, in Landlord's opinion, the Premises (exclusive of any Alterations
made to the Premises by Tenant) can be restored to its pre-existing condition
within two hundred seventy (270) days after the date of the damage or
destruction, Landlord shall, upon written notice from Tenant to Landlord of such
damage, except as provided in Section 11.3, promptly and with due diligence
repair any damage to the Premises (exclusive of any Alterations to the Premises
made by Tenant, which shall be promptly repaired by Tenant at its sole expense)
and, until such repairs are completed, the Rent shall be abated from the date of
damage or destruction in the same proportion that the rentable area of the
portion of the Premises which is unusable by Tenant in the conduct of its
business bears to the total rentable area of the Premises. If such repairs
cannot, in Landlord's opinion, be made within said two hundred seventy (270) day
period, then Landlord


<PAGE>   20

may, at its option, exercisable by written notice given to Tenant within thirty
(30) days after the date of the damage or destruction, elect to make the repairs
within a reasonable time after the damage or destruction, in which event this
Lease shall remain in full force and effect but the Rent shall be abated as
provided in the preceding sentence; if Landlord does not so elect to make the
repairs, then either Landlord or Tenant shall have the right, by written notice
given to the other within sixty (60) days after the date of the damage or
destruction, to terminate this Lease as of the date of the damage or
destruction.

        11.3 EXCEPTIONS TO LANDLORD'S OBLIGATIONS. Notwithstanding anything to
the contrary contained in this Article XI, Landlord shall have no obligation to
repair the Premises if either: (a) the Building in which the Premises are
located is so damaged as to require repairs to the Building exceeding twenty
percent (20%) of the full insurable value of the Building; or (b) Landlord
elects to demolish the Building in which the Premises are located; or (c) the
damage or destruction occurs less than two (2) years prior to the Expiration
Date, exclusive of option periods. Further, Tenant's Rent shall not be abated if
either (i) the damage or destruction is repaired within five (5) business days
after Landlord receives written notice from Tenant of the casualty, or (ii)
Tenant, or any officers, partners, employees, agents or invitees of Tenant, or
any assignee or subtenant of Tenant, is, in whole or in part, responsible for
the damage or destruction. Notwithstanding the foregoing, Landlord shall make
such repairs if the entire damage can be repaired within ninety (90) days from
the date of partial destruction.

        11.4 WAIVER. The provisions contained in this Lease shall supersede any
laws (whether statutory, common law or otherwise) now or hereafter in effect
relating to damage, destruction, self-help or termination, including California
Civil Code Sections 1932 and 1933.

                           ARTICLE XII - CONDEMNATION

        12.1 TAKING. If the entire Premises or so much of the Premises as to
render the balance unusable by Tenant shall be taken by condemnation, sale in
lieu of condemnation or in any other manner for any public or quasi-public
purpose (collectively "Condemnation"), and if Landlord, at its option, is unable
or unwilling to provide substitute premises containing at least as much rentable
area as described in Section 1.2 above, then this Lease shall terminate on the
date that title or possession to the Premises is taken by the condemning
authority, whichever is earlier

        12.2 AWARD. In the event of any Condemnation, the entire award for such
taking shall belong to Landlord. Tenant shall have no claim against Landlord or
the award for the value of any unexpired term of this Lease or otherwise. Tenant
shall be entitled to independently pursue a separate award in a separate
proceeding for Tenant's relocation costs directly associated with the taking,
provided such separate award does not diminish Landlord's award.

        12.3 TEMPORARY TAKING. No temporary talking of the Premises shall
terminate this Lease or entitle Tenant to any abatement of the Rent payable to
Landlord under this Lease; provided, further, that any award for such temporary
taking shall belong to Tenant to the extent that the award applies to any time
period during the Lease Term and to Landlord to the extent that the award
applies to any time period outside the Lease Term.

                            ARTICLE XIII - RELOCATION

        Landlord shall have the right, at its option upon not less than thirty
(30) days prior written notice to Tenant, to relocate Tenant and to substitute
for the Premises described above and the premises which Tenant subleases from
Compaq Corporation commonly letdown as Suite 250 ("Sublease Premises"), other
space in the Building containing at least as much rentable area as the Premises
and Sublease Premises described in Section 1.2 above. If Tenant is already in
occupancy of the Premises, then Landlord shall approve in advance the relocation
expenses for purposes of reimbursement for Tenant's reasonable moving and
telephone relocation expenses and for reasonable quantities of new stationery
upon submission to Landlord of receipts for such expenditures incurred by
Tenant.

                     ARTICLE XIV - ASSIGNMENT AND SUBLETTING

        14.1 RESTRICTION. Without the prior written consent of Landlord, Tenant
shall not, either voluntarily or by operation of law, assign, encumber, or
otherwise transfer this Lease


<PAGE>   21

or any interest herein, or sublet the Premises or any part thereof, or permit
the Premises to be occupied by anyone other than Tenant or Tenant's employees
(any such assignment, encumbrance, subletting, occupation or transfer is
hereinafter referred to as a "Transfer"). For purposes of this Lease the term
"Transfer" shall also include (a) if Tenant is a partnership the withdrawal or
change, voluntary, involuntary or by operation of law, of a majority of the
partners, or a transfer of a majority of partnership interests, within a twelve
month period, or the dissolution of the partnership, and (b) if Tenant is a
closely held corporation (i.e. whose stock is not publicly held and not traded
through an exchange or over the counter) or a limited liability company, the
dissolution, merger, consolidation, division, liquidation or other
reorganization of Tenant, or within a twelve month period: (i) the sale or other
transfer of more than an aggregate of 50% of the voting securities of Tenant
(other than to immediate family members by reason of gift or death) or (ii) the
sale, mortgage, hypothecation or pledge of more than an aggregate of 50% of
Tenant's net assets. A Transfer in violation of the foregoing shall be void and,
at Landlord's option, shall constitute a material breach of this Lease.
Notwithstanding anything contained in this Article XIV to the contrary, Tenant
shall have the right to assign the Lease or sublease the Premises, or any part
thereof, to an "Affiliate" without the prior written consent of Landlord, but
upon at least twenty (20) days' prior written notice to Landlord, provided that
said Affiliate is not in default under any other lease for space in a property
that is owned by Landlord or managed by Seagate or any of its affiliates. For
purposes of this provision, the term "Affiliate" shall mean any corporation or
other entity controlling, controlled by, or under common control with (directly
or indirectly) Tenant, including, without limitation, any parent corporation
controlling Tenant or any subsidiary that Tenant controls. The term "control,"
as used herein, shall mean the power to direct or cause the direction of the
management and policies of the controlled entity through the ownership of more
than fifty percent (50%) of the voting securities in such controlled entity.
Notwithstanding anything contained in this Article XIV to the contrary, Tenant
expressly covenants and agrees not to enter into any lease, sublease, license,
concession or other agreement for use, occupancy or utilization of the Premises
which provides for rental or other payment for such use, occupancy or
utilization based in whole or in part on the net income or profits derived by
any person from the property leased, used, occupied or utilized (other than an
amount based on a fixed percentage or percentages of receipts or sales), and
that any such purported lease, sublease, license, concession or other agreement
shall be absolutely void and ineffective as a conveyance of any right or
interest in the possession, use, occupancy or utilization of any part of the
Premises.

        14.2 NOTICE TO LANDLORD. If Tenant desires to assign this Lease or any
interest herein, or to sublet all or any part of the Premises, then at least
fifteen (15) days but not more than one hundred eighty (180) days prior to the
effective date of the proposed assignment or subletting, Tenant shall submit to
Landlord in connection with Tenant's request for Landlord's consent:

             14.2.1.Statement. A statement containing (a) the name and address
of the proposed assignee or subtenant; (b) such financial information with
respect to the proposed assignee or subtenant as Landlord shall reasonably
require; (c) the type of use proposed for the Premises; and (d) all of the
principal terms of the proposed assignment or subletting; and

             14.2.2.Original Documents. Four (4) originals of the assignment or
sublease on a form approved by Landlord and four (4) originals of the Landlord's
Consent to Sublease or Assignment and Assumption of Lease and Consent.

        14.3 LANDLORD'S RECAPTURE RIGHTS. At any time within fifteen (15)
business days after Landlord's receipt of all (but not less than all) of the
information and documents described in Section 14.02 above, Landlord may, at its
option by written notice to Tenant, elect to: (a) sublease the Premises or the
portion thereof proposed to be sublet by Tenant upon the same terms as those
offered to the proposed subtenant; (b) take an assignment of the Lease upon the
same terms as those offered to the proposed assignee; or (c) terminate the Lease
in its entirety or as to the portion of the Premises proposed to be assigned or
sublet, with a proportionate adjustment in the Rent payable hereunder if the
Lease is terminated as to less than all of the Premises. If Landlord does not
exercise any of the options described in the preceding sentence, then, during
the above-described twenty (20) business day period, Landlord shall either
consent or deny its consent to the proposed assignment or subletting.

        14.4 LANDLORD'S CONSENT; STANDARDS. Landlord's consent to a proposed
assignment or subletting shall not be unreasonably withheld; but, in addition to
any other


<PAGE>   22

grounds for denial, Landlord's consent shall be deemed reasonably withheld if,
in Landlord's good faith judgment: (a) the proposed assignee or subtenant does
not have the financial strength to perform its obligations under this Lease or
any proposed sublease; (b) the business and operations of the proposed assignee
or subtenant are not of comparable quality to the business and operations being
conducted by other tenants in the Building; (c) the proposed assignee or
subtenant intends to use any part of the Premises for a purpose not permitted
under this Lease; (d) either the proposed assignee or subtenant, or any person
which directly or indirectly controls, is controlled by, or is under common
control with the proposed assignee or subtenant occupies space in the Building,
or is negotiating with Landlord to lease space in the Building; (e) the proposed
assignee or subtenant is disreputable; or (f) the use of the Premises or the
Building by the proposed assignee or subtenant would, in Landlord's reasonable
judgment, impact the Building in a negative manner, including but not limited to
significantly increasing the pedestrian traffic in and out of the Building or
requiring any alterations to the Building to comply with applicable laws; (g)
the subject space is not regular in shape with appropriate means of ingress and
egress suitable for normal renting purposes; (h) the transferee is a government
(or agency or instrumentality thereof), or (i) Tenant has failed to cure a
default at the time Tenant requests consent to the proposed Transfer.

        14.5 ADDITIONAL RENT. If Landlord consents to any such assignment or
subletting, seventy-five percent (75%) of the amount by which all sums or other
economic consideration received by Tenant in Connection with such assignment or
subletting, whether denominated as rental or otherwise of standard marketing
expenses consistent with the then current market conditions in the San Francisco
Financial District, exceeds, in the aggregate, the total sum which Tenant is
obligated to pay Landlord under this Lease (prorated to reflect obligations
allocable to less than all of the Premises under a sublease) shall be paid to
Landlord promptly after receipt as additional Rent under the Lease without
affecting or reducing any other obligation of Tenant hereunder.

        14.6 LANDLORD'S COSTS. If Tenant shall Transfer this Lease or all or any
part of the Premises or shall request the consent of Landlord to any Transfer,
Tenant shall pay to Landlord as additional rent Landlord's costs related
thereto, including Landlord's reasonable attorneys' fees and a minimum fee to
Landlord of Five Hundred Dollars ($500.00).

        14.7 CONTINUING LIABILITY OF TENANT. Notwithstanding any Transfer,
Tenant shall remain as fully and primarily liable for the payment of Rent and
for the performance of all other obligations of Tenant contained in this Lease
to the same extent as if the Transfer had not occurred; provided, however, that
any act or omission of any transferee, other than Landlord, that violates the
terms of this Lease shall be deemed a violation of this Lease by Tenant.

        14.8 NON-WAIVER. The consent by Landlord to any Transfer shall not
relieve Tenant, or any person claiming through or by Tenant, terms, of the
obligation to obtain the consent of Landlord, pursuant to this Article XIV, to
any further Transfer. In the event of an assignment or subletting, Landlord may
collect rent from the assignee or the subtenant without waiving any rights
hereunder and collection of the rent from a person other than Tenant shall not
be a waiver of any of Landlord's rights under this Article XIV, an acceptance of
assignee or subtenant as Tenant, or a release of Tenant from the performance of
Tenant's obligations under this Lease. If Tenant shall default under this Lease
and fail to cure within the time permitted, Landlord is irrevocably authorized,
as Tenant's agent and attorney-in-fact, to direct any transferee to make all
payments under or in connection with the Transfer directly to Landlord (which
Landlord shall apply towards Tenant's obligations under this Lease) until such
default is cured.

                        ARTICLE XV - DEFAULT AND REMEDIES

        15.1 EVENTS OF DEFAULT BY TENANT. The occurrence of any of the following
shall constitute a material default and breach of this Lease by Tenant:

             15.1.1.Failure to Pay Rent. The failure by Tenant to pay Base Rent
or make any other payment required to be made by Tenant hereunder as and when
due.

             15.1.2.Abandonment. The abandonment of the Premises by Tenant or
the vacation of the Premises by Tenant.


<PAGE>   23

             15.1.3.Failure to Perform. The failure by Tenant to observe or
perform any other provision of this Lease to be observed or performed by Tenant,
other than those described in Sections 15.1.1 and 15.1.2 above, if such failure
continues for ten (10) days after written notice thereof by Landlord to Tenant;
provided, however, that if the nature of the default is such that it cannot be
cured within the ten (10) day period, no default shall exist if Tenant commences
the curing of the default within the ten (10) day period and thereafter
diligently prosecutes the same to completion. The ten (10) day notice described
herein shall be in lieu of, and not in addition to, any notice required under
Section 1161 of the California Code of Civil Procedure or any other law now or
hereafter in effect requiring that notice of default be given prior to the
commencement of an unlawful detainer or other legal proceeding.

             15.1.4.Bankruptcy. The making by Tenant or its Guarantor of any
general assignment for the benefit of creditors, the filing by or against Tenant
or its Guarantor of a petition under any federal or state bankruptcy or
insolvency laws (unless, in the case of a petition filed against Tenant or its
Guarantor the same is dismissed within thirty (30) days after filing); the
appointment of a trustee or receiver to take possession of substantially all of
Tenant's assets at the Premises or Tenant's interest in this Lease or the
Premises, when possession is not restored to Tenant within thirty (30) days; or
the attachment, execution or other seizure of substantially all of Tenant's
assets located at the Premises or Tenant's interest in this Lease or the
Premises, if such seizure is not discharged within thirty (30) days.

             15.1.5.Misstatement. Any material misrepresentation herein, or
material misrepresentation or omission in any financial statements or other
materials provided by Tenant or any Guarantor in connection with negotiating or
entering into this Lease or in connection with any Transfer under Section 14.1.

        15.2 LANDLORD'S RIGHT TO TERMINATE UPON TENANT DEFAULT. In the event of
any default by Tenant as provided in Section 15.1 above, Landlord shall have the
right to terminate this Lease and recover possession of the Premises by giving
written notice to Tenant of Landlord's election to terminate this Lease, in
which event Landlord shall be entitled to receive from Tenant: (a) the worth at
the time of award of any unpaid Rent which had been earned at the time of such
on award; plus (b) the worth at the time of award of the amount by which the
unpaid Rent which would have been earned after termination until the time of
award exceeds the amount of such rental loss Tenant proves could have been
reasonably avoided; plus (c) the worth at the time of award of the amount by
which the unpaid Rent for the balance of the term after the time of award
exceeds the amount of such rental loss that Tenant proves could be reasonably
avoided; plus (d) any other amount necessary to compensate Landlord for all the
detriment proximately caused by Tenant's failure to perform its obligations
under this Lease or which in the ordinary course of things would be likely to
result therefrom; and (e) at Landlord's election, such other amounts in addition
to or in lieu of the foregoing as may be permitted from time to time by
applicable law. As used in subsections (a) and (b) above, "worth at the time of
award" shall be computed by allowing interest on such amounts at the then
highest lawful rate of interest, but in no event to exceed one percent (1%) per
annum plus the rate established by the Federal Reserve Bank of San Francisco on
advances made to banks under Sections 13 and 13a of the Reserve Act ("discount
rate") prevailing at the time of award. As used in subsection (c) above, "worth
at the time of award" shall be computed by discounting such amount by (x) the
discount rate of the Federal Reserve Bank of San Francisco prevailing at the
time of award plus (y) one percent (1%).

        15.3 MITIGATION OF DAMAGES. If Landlord terminates this Lease or
Tenant's right to possession of the Premises, Landlord shall have no obligation
to mitigate Landlord's damages except to the extent required by applicable law.
If Landlord has not terminated this Lease or Tenant's right to possession of the
Premises, Landlord shall have no obligation to mitigate under any circumstances
and may permit the Premises to remain vacant or abandoned. If Landlord is
required to mitigate damages as provided herein: (a) Landlord shall be required
only to use reasonable efforts to mitigate, which shall not exceed such efforts
as Landlord generally uses to lease other space in the Building, (b) Landlord
will not be deemed to have failed to mitigate if Landlord or its affiliates
lease any other portions of the Building or other projects owned by Landlord or
its affiliates in the same geographic area, before reletting the Premises or any
portion of the Premises, and (c) any failure to mitigate as described herein
with respect to any period of time shall only reduce the Rent and other amounts
to which Landlord is entitled hereunder by the reasonable rental value of the
Premises during such period. In recognition that the value of the Building is
dependent on the rental rates and terms of leases


<PAGE>   24

therein, Landlord's rejection of a prospective replacement tenant based on an
offer of rentals below Landlord's published rates for new leases of comparable
space at the Building at the time in question, or at Landlord's option, below
the rates provided in this Lease, or containing terms less favorable than those
contained herein, shall not give rise to a claim by Tenant that Landlord failed
to mitigate Landlord's damages.

        15.4 LANDLORD'S RIGHT TO CONTINUE LEASE UPON TENANT DEFAULT. In the
event of a default of this Lease by Tenant, and if Landlord does not elect to
terminate this Lease as provided in Section 15.2 above, Landlord may, from time
to time, without terminating this Lease, enforce all of its rights and remedies
under this Lease or at law or in equity. Without limiting the foregoing,
Landlord has the remedy described in California Civil Code Section 1951.4
(Landlord may continue this Lease in effect after Tenant's default and recover
Rent as it becomes due, if Tenant has the right to Transfer, subject only to
reasonable limitations). In the event Landlord re-lets the Premises, to the
fullest extent permitted by law, the proceeds of any reletting shall be applied
first to pay to Landlord all costs and expenses of such reletting (including
without limitation, costs and expenses of retaking or repossessing the Premises,
removing persons and property therefrom, securing new tenants, including
expenses for redecoration, alterations and other costs in connection with
preparing the Premises for the new tenant, and if Landlord shall maintain and
operate the Premises, the costs thereof) and receivers' fees incurred in
connection with the appointment of and performance by a receiver to protect the
Premises and Landlord's interest under this Lease and any necessary or
reasonable alterations; second, to the payment of any indebtedness of Tenant to
Landlord other than Rent due and unpaid hereunder, third, to the payment of Rent
due and unpaid hereunder; and the residue, if any, shall be held by Landlord and
applied in payment of other or future obligations of Tenant to Landlord as the
same may become due and payable, and Tenant shall not be entitled to receive any
portion of such revenue.

        15.5 RIGHT OF LANDLORD TO PERFORM. All covenants and agreements to be
performed by Tenant under this Lease shall be performed by Tenant at Tenants
sole cost and expense. If Tenant shall fail to pay any sum of money, other than
Rent, required to be paid by it hereunder or shall fail to perform any other act
on its part to be performed hereunder, Landlord may, but shall not be obligated
to, make any payment or perform any such other act on Tenant's part to be made
or performed, without waiving or releasing Tenant of its obligations under this
Lease. Any sums so paid by Landlord and all necessary incidental costs, together
with interest thereon at the lesser of the maximum rate permitted by law if any
or twelve percent (12%) per annum from the date of such payment, shall be
payable to Landlord as additional rent on demand and Landlord shall have the
same rights and remedies in the event of nonpayment as in the case of default by
Tenant in the payment of Rent.

        15.6 DEFAULT UNDER OTHER LEASES. If the term of any lease, other than
this Lease, heretofore or hereafter made by Tenant for any office space in the
Building shall be terminated or terminable after the making of this Lease
because of any default by Tenant under such other lease, such fact shall empower
Landlord, at Landlord's sole option, to terminate this Lease by notice to Tenant
or to exercise any of the rights or remedies set forth in Section 15.2.

        15.7 NON-WAIVER. Nothing in this Article shall be deemed to affect
Landlord's rights to indemnification for liability or liabilities arising prior
to termination of this Lease or Tenant's right to possession for personal injury
or property damages under the indemnification clause or clauses contained in
this Lease. No acceptance by Landlord of a lesser sum than the Rent then due
shall be deemed to be other than on account of the earliest installment of such
rent due, nor shall any endorsement or statement on any check or any letter
accompanying any check or payment as rent be deemed an accord and satisfaction,
and Landlord may accept such check or payment without prejudice to Landlord's
right to recover the balance of such installment or pursue any other remedy in
the Lease provided. The delivery of keys to any employee of Landlord or to
Landlord's agent or any employee thereof shall not operate as a termination of
this Lease or a surrender of the Premises.

        15.8 CUMULATIVE REMEDIES. The specific remedies to which Landlord may
resort under the terms of the Lease are cumulative and are not intended to be
exclusive of any other remedies or means of redress to winch it may be lawfully
entitled in case of any breach or threatened breach by Tenant of any provisions
of the Lease. In addition to the other remedies provided in the Lease, Landlord
shall be entitled to a restraint by injunction of the violation or


<PAGE>   25

attempted or threatened violation of any of the covenants, conditions or
provisions of the Lease or to a decree compelling specific performance of any
such covenants, conditions or provisions.

        15.9 DEFAULT BY LANDLORD. Landlord's failure to perform or observe any
of its obligations under this Lease shall constitute a default by Landlord under
this Lease only if such failure shall continue for a period of thirty (30) days
(or the additional time, if any, which is reasonably necessary to promptly and
diligently cure the failure) after Landlord receives written notice from Tenant
specifying the default. The notice shall give in reasonable detail the nature
and extent of the failure and shall identify the Lease provision(s) containing
the obligation(s). If Landlord shall default in the performance of any of its
obligations under this Lease (after notice and opportunity to cure as provided
herein), Tenant may pursue any remedies available to it under the law and this
Lease, except that in no event shall Landlord be liable for punitive damages,
lost profits, business interruption, speculative, consequential or other such
damages. In recognition that Landlord must receive timely payments of Rent and
operate the Building, Tenant shall have no right of self-help to perform repairs
or any other obligation of Landlord, and shall have no right to withhold,
set-off, or abate Rent, except as specifically set forth in this Lease.

                 ARTICLE XVI - ATTORNEYS' FEES; INDEMNIFICATION

        16.1 ATTORNEYS' FEES. If either Landlord or Tenant shall commence any
action or other proceeding against the other arising out of, or relating to,
this Lease or the Premises, the prevailing party shall be entitled to recover
from the losing party, in addition to any other relief, its actual attorneys'
fees irrespective of whether or not the action or other proceeding is prosecuted
to judgment and irrespective of any court schedule of reasonable attorneys'
fees. In addition, Tenant shall reimburse Landlord, upon demand, for all
reasonable attorneys' fees incurred in collecting Rent or otherwise seeking
interpretation of this Lease or enforcement against Tenant, its sublessees and
assigns, of Tenants obligations under this Lease.

        16.2 INDEMNIFICATION. Should Landlord be made a party to any litigation
instituted by Tenant against a party other than Landlord, or by a third party
against Tenant, Tenant shall indemnify, hold harmless and defend Landlord from
any and all loss, cost, liability, damage or expense incurred by Landlord,
including attorneys' fees, in connection with the litigation.

                   ARTICLE XVII - SUBORDINATION AND ATTORNMENT

        17.1 SUBORDINATION. This Lease, and the rights of Tenant hereunder, are
and shall be subject and subordinate to the interests of (i) all present and
future ground leases and master leases of all or any part of the Building; (ii)
present and future mortgages and deeds of trust encumbering all or any part of
the Building; (iii) all past and future advances made under any such mortgages
or deeds of trust; and (iv) all renewals, modifications, replacements and
extensions of any such ground leases, master leases, mortgages and deeds of
trust; provided, however, that any lessor under any such ground lease or master
lease or any mortgagee or beneficiary under any such mortgage or deed of trust
(any such lessor, mortgagee or beneficiary is hereinafter referred to as a
"Mortgagee") shall have the right to elect, by written notice given to Tenant,
to have this Lease made superior in whole or in part to any such ground lease,
master lease, mortgage or deed of trust (or subject and subordinate to such
ground lease, master lease, mortgage or deed of trust but superior to any junior
mortgage or junior deed of trust). Upon demand, Tenant shall execute,
acknowledge and deliver any instruments reasonably requested by Landlord or any
such Mortgagee to effect the purposes of this Section 17.1. Such instruments may
contain, among other things, provisions to the effect that such Mortgagee
(hereafter, for the purposes of this Section 17.1, a "Successor Landlord") shall
(a) not be liable for any act or omission of Landlord or its predecessors, if
any, prior to the date of such Successor Landlord's succession to Landlord's
interest under this Lease; (b) not be subject to any offsets or defenses which
Tenant might have been able to assert against Landlord or its predecessors, if
any, prior to the date of such Successor Landlord's succession to Landlord's
interest under this Lease; (c) not be liable for the return of any security
deposit under the Lease unless the same shall have actually been deposited with
such Successor Landlord; (d) be entitled to receive notice of any Landlord
default under this Lease plus a reasonable opportunity to cure such default
prior to Tenant having any right or ability to terminate this Lease as a result
of such Landlord default; (e) not be bound by any rent or additional rent which
Tenant might have paid for more than the current month to Landlord; (f) not be
bound by any amendment or modification of the Lease or


<PAGE>   26

any cancellation of the same made without Successor Landlord's prior written
consent; (g) not be bound by any obligation to make any payment to Tenant which
was required to be made prior to the time such Successor Landlord succeeded to
Landlord's interest, and (h) not be bound by any obligation under the Lease to
perform any work or to make any improvements to the demised Premises. Any
obligations of any Successor Landlord under its respective lease shall be
non-recourse as to any assets of such Successor Landlord other than its interest
in the Building and its related improvements. Not withstanding the foregoing,
Tenant's Subordination shall only be effective as to the extent that the future
Mortgagee agrees that this Lease shall survive the termination of the
Mortgagee's interest by lapse of time, foreclosure or otherwise so long as
Tenant is not in default under this Lease.

        17.2 ATTORNMENT. If the interests of Landlord under the Lease shall be
transferred to any superior Mortgagee or Successor Landlord or other purchaser
or person taking title to the Building by reason of the termination of any
superior lease or the foreclosure of any superior mortgage or deed of trust,
Tenant shall be bound to such Successor Landlord under all of the terms,
covenants and conditions of the Lease for the balance of the term thereof
remaining and any extensions or renewals thereof which may be effected in
accordance with any option therefor in the Lease, with the same force and effect
as if Successor Landlord were the landlord under the Lease, and Tenant shall
attorn to and recognize as Tenant's landlord under this Lease such Successor
Landlord, as its landlord, said attornment to be effective and self-operative
without the execution of any further instruments upon Successor Landlord's
succeeding to the interest of Landlord under the Lease. Tenant acknowledges that
Landlord is (a) the assignee of the lessor's interest in that certain Ground
Lease dated June 11, 1963 ("Existing Ground Lease") for the land underlying the
Building, and (b) the assignee of the lessee's interest in the Ground Lease.
Upon expiration or termination of the Existing Ground Lease, Tenant will attorn
to and continue to recognize Landlord as the landlord under this Lease. Tenant
shall, upon demand, execute any documents reasonably requested by any such
person to evidence the adornment described in this Section 17.2. Concurrently,
upon written request from Tenant, and provided Tenant is not in default under
this Lease, Landlord agrees to use diligent, commercially reasonable efforts to
obtain a Non-Disturbance Agreement from the Successor Landlord. Such
Non-Disturbance Agreement may be embodied in the Mortgagee's customary form of
Subordination and Non-Disturbance Agreement. If, after exerting diligent,
commercially reasonable efforts, Landlord is unable to obtain a Non-Disturbance
Agreement from any such Mortgagee, Landlord shall have no further obligation to
Tenant with respect thereto.

        17.3 MORTGAGEE PROTECTION. Tenant agrees to give any Mortgagee, by
registered or certified mail, a copy of any notice of default served upon
Landlord by Tenant, provided that prior to such notice Tenant has been notified
in writing (by way of service on Tenant of a copy of Assignment of Rents and
Leases, or otherwise) of the address of such Mortgagee (hereafter the "Notified
Party"). Tenant further agrees that if Landlord shall have failed to cure such
default within twenty (20) days after such notice to Landlord (or if such
default cannot be cured or corrected within that time, then such additional time
as may be necessary if Landlord has commenced within such twenty (20) days and
is diligently pursuing the remedies or steps necessary to cure or correct such
default), then the Notified Party shall have an additional thirty (30) days
within which to cure or correct such default (or if such default cannot be cured
or corrected within that time, then such additional time as may be necessary if
the Notified Party has commenced within such thirty (30) days and is diligently
pursuing the remedies or steps necessary to cure or correct such default). Until
the time allowed, as aforesaid, for the Notified Party to cure such default has
expired without cure, Tenant shall have no right to, and shall not, terminate
this Lease on account of Landlord's default.

                          ARTICLE XVIII - MISCELLANEOUS

        18.1 QUIET ENJOYMENT. Provided that Tenant performs all of its
obligations hereunder, Tenant shall have and peaceably enjoy the Premises during
the Lease Term free of claims by or through Landlord, subject to all of the
terms and conditions contained in this Lease.

        18.2 RULES AND REGULATIONS. The Rules and Regulations attached hereto as
Exhibit C are hereby incorporated by reference herein and made a part hereof.
Tenant shall abide by, and faithfully observe and comply with the Rules and
Regulations and any reasonable and non-discriminatory amendments, modifications
and/or additions thereto as may hereafter be adopted and published by written
notice to tenants by Landlord for the safety, care, security, good order and/or
cleanliness of the Premises and/or the Building. Landlord shall not be liable


<PAGE>   27

to Tenant for any violation of such rules and regulations by any other tenant or
occupant of the Building.

        18.3 ESTOPPEL CERTIFICATES. Tenant agrees at any time and from time to
time, upon not less than ten (10) business days prior written notice from
Landlord, to execute, acknowledge and deliver to Landlord a statement in writing
addressed and certifying to Landlord, to any current or prospective Mortgagee or
any assignee thereof, to any prospective purchaser of the land, improvements or
both comprising the Building, and to any other party designated by Landlord,
that this Lease is unmodified and in full force and effect (or if there have
been modifications, that the same is in full force and effect as modified and
stating the modifications); that Tenant has accepted possession of the Premises,
which are acceptable in all respects, and that any improvements required by the
terms of this Lease to be made by Landlord have been completed to the
satisfaction of Tenant; that Tenant is in full occupancy of the Premises; that
no rent has been paid more than thirty (30) days in advance; that the first
month's Base Rent has been paid; that Tenant is entitled to no free rent or
other concessions except as stated in this Lease; that Tenant has not been
notified of any previous assignment of Landlord's or any predecessor landlord's
interest under this Lease; the dates to which Base Rent, additional rental and
other charges have been paid; that Tenant, as of the date of such certificate,
has no charge, lien or claim of setoff under this Lease or otherwise against
Base Rent, additional rental or other charges due or to become due under this
Lease; that Landlord is not in default in performance of any covenant, agreement
or condition contained in this Lease; or any other matter relating to this Lease
or the Premises or, if so, specifying each such default. If there is a Guaranty
under this Lease, said Guarantor shall confirm the validity of the Guaranty by
joining in the execution of the Estoppel Certificate or other documents so
requested by Landlord or Mortgagee. In addition, in the event that such
certificate is being given to any Mortgagee, such statement may contain any
other provisions customarily required by such Mortgagee including, without
limitations an agreement on the part of Tenant to furnish to such Mortgagee,
written notice of any Landlord default and a reasonable opportunity for such
Mortgagee to cure such default prior to Tenant being able to terminate this
Lease. Any such statement delivered pursuant to this Section may be relied upon
by Landlord or any Mortgagee, or prospective purchaser to whom it is addressed
and such statement, if required by its addressee, may so specifically state. If
Tenant does not execute, acknowledge and deliver to Landlord the statement as
and when required herein, Landlord is hereby granted an irrevocable power of
attorney, coupled with an interest, to execute such statement on Tenant's
behalf, which statement shall be binding on Tenant to the same extent as if
executed by Tenant.

        18.4 ENTRY BY LANDLORD. Landlord may enter the Premises at all
reasonable times to: inspect the same; exhibit the same to prospective
purchasers, Mortgagees or tenants; determine whether Tenant is complying with
all of its obligations under this Lease; supply janitorial and other services to
be provided by Landlord to Tenant under this Lease; post notices of
non-responsibility; and make repairs or improvements in or to the Building or
the Premises; provided, however, that all such work shall be done as promptly as
reasonably possible and so as to cause as little interference to Tenant as
reasonably possible. Tenant hereby waives any claim for damages for any injury
or inconvenience to, or interference with, Tenant's business, any loss of
occupancy or quiet enjoyment of the Premises or any other loss occasioned by
such entry. Landlord at all times shall have and retain a key with which to
unlock all of the doors in, on or about the Premises (excluding Tenant's vaults,
safes and similar areas designated by Tenant in writing in advance), and
Landlord shall have the right to use any and all means by which Landlord may
deem proper to open such doors to obtain entry to the Premises, and any entry to
the Premises obtained by Landlord by any such means, or otherwise, shall not
under any circumstances be or construed to be a forcible or unlawful entry into
or a detainer of the Premises or an eviction, actual or constructive, of Tenant
from any part of the Premises. Such entry by Landlord shall not act as a
termination of Tenant's duties under this Lease. If Landlord shall be required
to obtain entry by means other than a key provided by Tenant, the cost of such
entry shall be payable by Tenant to Landlord as additional rent.

        18.5 LANDLORD'S LEASE UNDERTAKINGS. Notwithstanding anything to the
contrary contained in this Lease or in any exhibits, Riders or addenda hereto
attached (collectively the "Lease Documents"), it is expressly understood and
agreed by and between the parties hereto that: (a) the recourse of Tenant or its
successors or assigns against Landlord with respect to the alleged breach by or
on the part of Landlord of any representation, warranty, covenant, undertaking
or agreement contained in any of the Lease Documents or otherwise arising out of
Tenant's use of the Premises or the Building (collectively, "Landlord's Lease


<PAGE>   28

Undertaking") shall extend only to Landlord's interest in the real estate of
which the Premises demised under the Lease Documents are a part ("Landlord's
Real Estate") and not to any other assets of Landlord or its beneficiaries; and
(b) no personal liability or personal responsibility of any sort with respect to
any of Landlord's Lease Undertakings or any alleged breach thereof is assumed
by, or shall at any time be asserted or enforceable against, Landlord, OTR," an
Ohio general partnership, Seagate Properties, Inc., Seagate Realty Advisors, or
against any of their respective directors, officers, employees, agents,
constituent partners, beneficiaries, trustees or representatives. Tenant
acknowledges that this Lease is executed by certain general partners of OTR
and/or Seagate Realty Advisors, not individually but solely on behalf of, and as
the authorized nominee and agent for, the State Teachers Retirement Board of
Ohio, and Tenant and all persons dealing with Landlord waive any right to bring
a cause of action against the individuals executing this Lease on behalf of
Landlord and must look solely to the assets of State Teachers Retirement Board
of Ohio for the enforcement of any claim against Landlord.

        18.6 TRANSFER OF LANDLORD'S INTEREST. In the event of any transfer of
Landlord's interest in the Building, Landlord shall be automatically freed and
relieved from all applicable liability with respect to performance of any
covenant or obligation on the part of Landlord under this Lease occurring after
the date of such transfer, provided any deposits or advance rents held by
Landlord are turned over to the grantee and said grantee expressly assumes,
subject to the limitations of this Lease, all the terms, covenants and
conditions of this Lease to be performed on the part of Landlord, it being
intended hereby that the covenants and obligations contained in this Lease on
the part of Landlord shall, subject to all the provisions of this Lease, be
binding on Landlord, its successors and assigns, only during their respective
periods of ownership.

        18.7 HOLDOVER. If Tenant holds possession of the Premises after the
expiration or termination of the Lease Term, by lapse of time or otherwise,
Tenant shall become a tenant at sufferance upon all of the terms contained
herein, except as to Lease Term and Rent. During such holdover period, Tenant
shall pay to Landlord a monthly rental equivalent to one hundred fifty percent
(150%) of the Rent payable by Tenant to Landlord with respect to the last month
of the Lease Term and Rent for the first sixty (60) days after expiration or
termination of the Lease; after the first sixty (60) day period after
expiration, Tenant shall pay to Landlord a monthly rental equivalent to two
hundred percent (200%) of the Rent payable by Tenant to Landlord with respect to
the last month of the Lease Term. The monthly rent payable for such holdover
period shall in no event be construed as a penalty or as liquidated damages for
such retention of possession. Without limiting the foregoing Tenant hereby
agrees to indemnify, defend and hold harmless Landlord, its beneficiary, and
their respective agents, contractors and employees, from and against any and all
claims, liabilities, actions, losses, damages (including without limitation,
direct, indirect, incidental and consequential) and expenses (including, without
limitation, court costs and reasonable attorneys' fees) asserted against or
sustained by any such party and arising from or by reason of such retention of
possession, which obligations shall survive the expiration or termination of the
Lease Term.

        18.8 NOTICES. All notices which Landlord or Tenant may be required, or
may desire, to serve on the other may be served, as an alternative to personal
service, by mailing the same by registered or certified mail, postage prepaid,
addressed to Landlord at the address for Landlord get forth in Section 1.13
above and to Tenant at the address for Tenant set forth in Section 1.14 above,
or, from and after the Commencement Date, to Tenant at the Premises whether or
not Tenant has departed from, abandoned or vacated the Premises, or addressed to
such other address or addresses as either Landlord or Tenant may from time to
time designate to the other in writing. Any notice shall be deemed to have been
served at the time the same was posted.

        18.9 BROKERS. The parties recognize as the broker(s) who procured this
Lease the firm(s) specified in Section 1.15 and agree that Landlord shall be
solely responsible for the payment of any brokerage commissions to said
broker(s), and that Tenant shall have no responsibility therefor unless written
provision to the contrary has been made a part of this Lease. If Tenant has
dealt with any other person or real estate broker in respect to leasing,
subleasing or renting space in the Building, Tenant shall be solely responsible
for the payment of any fee due said person or firm and Tenant shall protect,
indemnify, hold harmless and defend Landlord from any liability in respect
thereto.


<PAGE>   29

        18.10 COMMUNICATIONS AND COMPUTER LINES. Tenant may, in a manner
consistent with the provisions and requirements of this Lease, install,
maintain, replace, remove or use any communications or computer wires, cables
and related devices (collectively the "Lines") at the Building in or serving the
Premises, provided: (a) Tenant shall obtain Landlord's prior written consent,
which consent may be conditioned as required by Landlord, (b) if Tenant at any
time uses any equipment that may create an electromagnetic field exceeding the
normal insulation ratings of ordinary twisted pair riser cable or cause
radiation higher than normal background radiation, the Lines therefor (including
riser cables) shall be appropriately insulated to prevent such excessive
electromagnetic fields or radiation, and (c) Tenant shall pay all costs in
connection therewith. Landlord reserves the right to require that Tenant remove
any Lines which are installed in violation of these provisions.

             18.10.1. NEW LINES. Landlord may (but shall not have the obligation
to): (a) install new Lines at the Property, and (b) create additional space for
Lines at the Property, and adopt reasonable and uniform rules and regulations
with respect to the Lines.

             18.10.2. LINE PROBLEMS. Notwithstanding anything to the contrary
contained in this Lease, Landlord reserves the right to require that Tenant
remove any or all Lines installed by or for Tenant within or serving the
Premises. Tenant shall not, without the prior written consent of Landlord in
each instance, grant to any third party a security interest or lien in or on the
Lines, and any such security interest or lien granted without Landlord's written
consent shall be null and void. Except to the extent arising from the
intentional or negligent acts of Landlord or Landlord's agents or employees,
Landlord shall have no liability for damages arising from, and Landlord does not
warrant that Tenant's use of any Lines will be free from the following,
(collectively called "Line Problems"): (a) any eavesdropping or wire-tapping by
unauthorized parties, (b) any failure of any Lines to satisfy Tenants
requirements, or (c) any shortages, failures, variations, interruptions,
disconnections, loss or damage caused by the installation, maintenance,
replacement, use or removal of Lines by or for other tenants or occupants at the
Property. Under no circumstances shall any Line Problems be deemed an actual or
constructive eviction of Tenant, render Landlord liable to Tenant for abatement
of Rent; or relieve Tenant from performance of Tenant's obligations under this
Lease. Landlord in no event shall be liable for damages by reason of loss of
profits, business interruption or other consequential damage arising from any
Line Problems.

        18.11 ENTIRE AGREEMENT. This Lease contains all of the agreements and
understandings relating to the leasing of the Premises and the obligations of
Landlord and Tenant in connection with such leasing. Landlord has not made, and
Tenant is not relying upon, any warranties, or representations, promises or
statements made by Landlord or any agent of Landlord, except as expressly set
forth herein. This Lease supersedes any and all prior agreements and
understandings between Landlord and Tenant and alone expresses the agreement of
the parties.

        18.12 AMENDMENTS. This Lease shall not be amended, changed or modified
in any way unless in writing executed by Landlord and Tenant. Landlord shall not
have waived or released any of its rights hereunder unless in writing and
executed by Landlord.

        18.13 SUCCESSORS. Subject to the limitations expressly provided herein,
this Lease and the obligations of Landlord and Tenant contained herein shall
bind and benefit the successors and assigns of the parties hereto.

        18.14 FORCE MAJEURE. Landlord shall incur no liability to Tenant with
respect to, and shall not be responsible for any failure to perform, any of
Landlord's obligations hereunder if such failure is caused by any reason beyond
the control of Landlord including, but not limited to, strike, labor trouble,
governmental rule, regulations, ordinance, statute or interpretation, or by
fire, earthquake, civil commotion, or failure or disruption of utility services.
The amount of time for Landlord to perform any of Landlord's obligations shall
be extended by the amount of time Landlord is delayed in performing such
obligation by reason of any force majeure occurrence whether similar to or
different from the foregoing types of occurrences.

        18.15 SURVIVAL OF OBLIGATIONS. Any obligations of Tenant accruing prior
to the expiration of the Lease shall survive the expiration or earlier
termination of the Lease, and Tenant shall promptly perform all such obligations
whether or not this Lease has expired or been terminated.


<PAGE>   30

        18.16 LIGHT AND AIR. No diminution or shutting off of any light, air or
view by any structure now or hereafter erected shall in any manner affect this
Lease or the obligations of Tenant hereunder, or increase any of the obligations
of Landlord hereunder.

        18.17 GOVERNING LAW. This Lease shall be governed by, and construed in
accordance with, the laws of the State of California.

        18.18 SEVERABILITY. In the event any provision of this Lease is found to
be unenforceable, the remainder of this Lease shall not be affected, and any
provision found to be invalid shall be enforceable to the extent permitted by
law. The parties agree that in the event two different interpretations may be
given to any provision hereunder, one of which will render the provision
unenforceable, and one of which will render the provision enforceable, the
interpretation rendering the provision enforceable shall be adopted.

        18.19 CAPTIONS. All captions, headings, titles, numerical references and
computer highlighting are for convenience only and shall have no effect on the
interpretation of this Lease.

        18.20 INTERPRETATION. Tenant acknowledges that it has read and reviewed
this Lease and that it has had the opportunity to confer with counsel in the
negotiation of this Lease. Accordingly, this Lease shall be construed neither
for nor against Landlord or Tenant, but shall be given a fair and reasonable
interpretation in accordance with the plain meaning of its terms and the intent
of the parties.

        18.21 INDEPENDENT COVENANTS. Each covenant, agreement, obligation or
other provision of this Lease to be performed by Tenant are separate and
independent covenants of Tenant, and not dependent on any other provision of the
Lease.

        18.22 NUMBER AND GENDER. All terms and words used in this Lease,
regardless of the number or gender in which they are used, shall be deemed to
include the appropriate number and gender, as the context may require.

        18.23 TIME IS OF THE ESSENCE. Time is of the essence of this Lease and
the performance of all obligations hereunder.

        18.24 JOINT AND SEVERAL LIABILITY. If Tenant comprises more than one
person or entity, or if this Lease is guaranteed by any party, all such persons
shall be jointly and severally liable for payment of rents and the performance
of Tenant's obligations hereunder.

        18.25 EXHIBITS. Exhibits A (Floor Plan), B (Work Letter Agreement), C
(Rules and Regulations), and E (Acceptance Letter), and are incorporated into
this Lease by reference and made a part hereof.

        18.26 OFFER TO LEASE. The submission of this Lease to Tenant or its
broker or other agent, does not constitute an offer to Tenant to lease the
Premises. This Lease shall have no force and effect until (a) it is executed and
delivered by Tenant to Landlord, and (b) it is fully reviewed, executed and
delivered by Landlord to Tenant; provided, however, that upon execution of this
Lease by Tenant and delivery to Landlord, such execution and delivery by Tenant
shall, in consideration of the time and expense incurred by Landlord in
reviewing the Lease and Tenant's credit, constitute an offer by Tenant to Lease
the Premises upon the terms and conditions set forth herein (which offer to
Lease shall be irrevocable for twenty (20) business days following the date of
delivery).

        18.27 NO COUNTERCLAIM; CHOICE OF LAWS. It is mutually agreed that in the
event Landlord commences any summary proceeding for non-payment of Rent, Tenant
will not interpose any counterclaim of whatever nature or description in any
such proceeding. In addition, Tenant hereby submits to local jurisdiction in the
State of California and agrees that any action by Tenant against Landlord shall
be instituted in the State of California and that Landlord shall have personal
jurisdiction over Tenant for any action brought by Landlord against Tenant in
the State of California.

        18.28 RIGHTS RESERVED BY LANDLORD. Landlord reserves the following
rights exercisable without notice (except as otherwise expressly provided to the
contrary in this Lease) and without being deemed an eviction or disturbance of
Tenant's use or possession of the


<PAGE>   31

Premises or giving rise to any claim for set-off or abatement of Rent: (a) to
change the name or street address of the Building; (b) to install, affix and
maintain all signs on the exterior and/or interior of the Building; (c) to
designate and/or approve prior to installation, all types of signs, window
shades, blinds, drapes, awnings or other similar items, and all internal
lighting that may be visible from the exterior of the Premises and,
notwithstanding the provisions of Article IX, the design, arrangement, style,
color and general appearance of the portion of the Premises visible from the
exterior, and contents thereof, including, without limitation, furniture,
fixtures, equipment, art work, wall coverings, carpet and decorations, and all
changes, additions and removals thereto, shall, at all times have the appearance
of premises having the same type of exposure and used for substantially the same
purposes that are generally prevailing in comparable office buildings in the
area; (d) to change the arrangement of entrances, doors, corridors, elevators
and/or stairs in the Building, provided no such change shall materially
adversely affect access to the Premises; (e) to grant any party the exclusive
right to conduct any business or render any service in the Building, provided
such exclusive right shall not operate to prohibit Tenant from using the
Premises for the purposes permitted under this Lease; (f) to prohibit the
placement of vending or dispensing machines of any kind in or about the Premises
other than for use by Tenant's employees; (g) to prohibit the placement of video
or other electronic games in the Premises; (h) to have access for Landlord and
other tenants of the Building to any mail chutes and boxes located in or on the
Premises according to the rules of the United States Post Office and to
discontinue any mail chute business in the Building; (i) to close the Building
after normal business hours, except that Tenant and its employees and invitees
shall be entitled to admission at all times under such rules and regulations as
Landlord prescribes for security purposes; (j) to install, operate and maintain
security systems which monitor, by close circuit television or otherwise, all
persons entering or exiting the Building; (k) to install and maintain pipes,
ducts, conduits, wires and structural elements located in the Premises which
serve other parts or other tenants of the Building; and (l) to retain at all
times master keys or pass keys to the Premises. Any violation of this provision
shall be deemed a material breach of this Lease.

        18.29 ASBESTOS. Tenant acknowledges that it has been expressly disclosed
to Tenant by Landlord's Managing Agent that the Building and the Premises
contain asbestos containing materials ("ACM"). The acknowledgment by Tenant of
the ACM does not in any manner impose any liability or responsibility on Tenant
for removal, treatment, or abatement of such ACM or any responsibility
whatsoever regarding such ACM provided, however, that Tenant shall comply with
all applicable laws and regulations in connection with any work in the Premises
including, but not limited to, work which requires entry into the ceiling.

        18.30 ADR PROCESS. If Landlord and Tenant are unable for any reason to
timely agree on (i) the Prevailing Rental Rate referenced in Section 3.2.1, if
applicable, or (ii) the correction of alleged errors in Landlord's Statement as
provided in Section 4.4. or (iii) the amount of Base Rent to be abated if an
interruption of services or utilities occurs as described in Section 7.2 or an
impairment to the Premises occurs due to Landlord's failure to maintain or
repair as described in Section 8.2 (collectively, "SPECIFIED Disputes"), then
Landlord and Tenant agree that all Specified Disputes shall be resolved pursuant
to the neutral binding alternative dispute resolution process ("ADR PROCESS")
described below. Landlord and Tenant (acting together or individually) shall
submit a notice of a Specified Dispute ("NOTICE OF DISPUTE") to JAMS (defined
below) which Notice sets forth the details of the dispute and requests JAMS to
implement the ADR Process set forth below.

        (A) ADR Process. The Notice of Dispute shall be delivered to the San
Francisco office of Judicial Arbitration and Mediation Service ("JAMS") for
binding resolution pursuant to the ADR Process. The ADR Process shall be
conducted according to the following procedure:

                  (i) The ADR Process shall be conducted in San Francisco,
California.

                  (ii) JAMS shall promptly select a single retired California
Superior Court Judge to be the hearing officer ("HEARING OFFICER"). The Hearing
Officer shall not have any actual or perceived conflict of interest with
Landlord or Tenant, any affiliate or subsidiary or their respective counsel and
absent any conflict, neither Landlord or Tenant shall have the right to object
to the Hearing Officer. The Hearing Officer shall have extensive and recent
civil trial experience and shall not have been primarily a criminal courts judge
during


<PAGE>   32

his/her career. The first hearing day shall be scheduled not later than thirty
(30) calendar days following appointment of the Hearing Officer and the hearing
process shall be concluded within thirty (30) calendar days from commencement.

                  (iii) The Hearing Officer shall preside over the ADR Process,
shall accept relevant evidence, and may (in her/her discretion) hear live
testimony of the parties and their expert and other witnesses, examine and
cross-examine the parties and their witnesses, allow counsel to examine and
cross-examine witnesses, hear arguments of counsel, and otherwise conduct and
control a hearing as if he/she were sitting as a California Superior Court Judge
without a jury. At the conclusion of the hearing, the Hearing Officer shall
orally announce a tentative decision as to the disagreement(s) which form the
basis of the Specified Dispute(s). In announcing the tentative decision and in
rendering the Final Award (defined below), the Hearing Officer shall be required
to follow California law in the interpretation of any document or agreement
(including this Lease), in admitting evidence and in fashioning a remedy. The
Hearing Officer shall not have the power or authority to award any amount in the
nature or character of punitive or exemplary damages, but shall have the power
to issue an award for compensatory damages based on breach or default of the
Lease, shall have the power to issue injunctive or other equitable relief where
appropriate, shall have the power to issue a judgment for unlawful detainer of
the Premises, and shall have the power to issue an award for attorneys' fees and
costs as allowed by this Lease.

                  (iv) Within ten (l0) calendar days following conclusion of the
oral hearing, the Hearing Officer shall prepare and deliver to each of the
parties a written decision, accompanied by a statement of facts, law, underlying
reasons and conclusions necessary to fully explain his/her decision ("FINAL
AWARD"). If the Final Award requires payment by one party of any amount of money
to the other party, the Hearing Officer shall require that payment be made
within thirty (30) calendar days following issuance of the Final Award, and, if
payment is not timely made, the Final Award shall provide the party to whom
payment is due with the right but not the obligation to seek immediate
enforcement of the Final Award by a court of competent jurisdiction.

                  (v) The Final Award shall be binding on each party to the
dispute, shall be admissible in any court of law for any purpose reasonably
related thereto (including, but not limited to, for the purpose of determining
whether or not a breach or default under the Lease has occurred), and either
party may petition the California Superior Court to enter the Final Award as the
final judgement and award of the court and/or to enforce enforcement of a Final
Award.

                  (vi) Each party shall pay one-half of the fees and costs for
JAMS and the Hearing Officer. If advance payment or deposit is required prior to
commencement of the ADR Process, each party to the dispute hereby represents and
warrants that it will timely pay and deposit said amount. The failure to timely
pay any amounts requested by the Hearing Officer or JAMS shall constitute an
immediate and material event of default and if said amounts are not timely paid
following receipt of a five (5) business day notice and demand to pay, the
Hearing Officer shall be required (without the taking of any evidence or
testimony) to issue a Final Award in favor of the party to the dispute timely
paying its fees, on the terms and conditions requested by said party, which
shall be final and binding.

        18.31 MISCELLANEOUS SIGNAGE. Upon move-in, Tenant shall receive from
Landlord at Landlord's cost:

    l)  One suite sign insert which includes insert and one line of verbiage

    2)  One elevator lobby strip

    3)  One main lobby strip for each 750 square feet leased

    4)  Two suite keys and two restroom guest keys

All signage shall be in accordance with Building Standard signage specification
and is subject to Landlord's prior approval. Additional signage and keys may be
purchased through Seagate Properties, Inc.

        IN WITNESS WHEREOF, the parties hereto have executed this lease as of
the date first above written.


<PAGE>   33

LANDLORD:                              TENANT:

OTR, an Ohio general                   CHEMCONNECT, INC., A DELAWARE
partnership, as Nominee of The         CORPORATION
State Teachers Retirement
Board of Ohio, a statutory
organization created by the
laws of Ohio                           By:
                                          --------------------------------------
By: SEAGATE REALTY ADVISORS, A         Its:
    CALIFORNIA GENERAL                     -------------------------------------
    PARTNERSHIP, ITS DULY              Date:
    AUTHORIZED AGENT                        ------------------------------------

By:
   -----------------------------------
Its:
    ----------------------------------
Date:
     ---------------------------------


<PAGE>   34

                                    EXHIBIT A

                             FLOOR PLAN OF PREMISES

This Exhibit A is attached to and made a part of that certain Lease dated
September 20, 1999, by and between OTR, AND OHIO GENERAL PARTNERSHIP, AS NOMINEE
FOR THE STATE TEACHER'S RETIREMENT BOARD OF OHIO, a statutory organization
created by the laws of Ohio, as Landlord, and CHEMCONNECT, INC. a Delaware
corporation as Tenant, in the Building commonly referred to as 44 Montgomery
Street.

                            [Diagram of Leased Space]




























                                    EXHIBIT A
<PAGE>   35

                                    EXHIBIT B

                              WORK LETTER AGREEMENT

        This Work Letter Agreement ("Work Letter") is executed simultaneously
with that certain Office Lease (the "Lease") between CHEMCONNECT, INC., a
Delaware corporation as "Tenant", and OTR, an Ohio general partnership, as
Nominee of The State Teachers Retirement Board of Ohio, a statutory organization
created by the laws of Ohio, as "Landlord", relating to demised premises
("Premises") at the building commonly known as 44 MONTGOMERY STREET (the
"Building"), which Premises are more fully identified in the Lease. Capitalized
terms used herein, unless otherwise defined in this Work Letter, shall have the
respective meanings ascribed to them m the Lease.

        For and in consideration of the agreement to lease the Premises and the
mutual covenants contained herein and in the Lease, Landlord and Tenant hereby
agree as follows:

        1. Tenant's Initial Plans; the Work. Tenant desires Landlord to perform
certain leasehold improvement work in the Premises in substantial accordance
with the plan or plans (collectively, the "Initial Plan") which if not attached
hereto as Schedule 1, both Landlord and Tenant shall make a good faith effort to
have a mutually acceptable Initial Plan drawn within fifteen (15) days hereof,
and will then be made an attachment to the Lease. Such work, as shown in the
Initial Plan and as more fully detailed in the Working Drawings (as defined and
described in Paragraph 2 below), shall be hereinafter referred to as the "Work".
Not later than September 15, 1999, Tenant shall furnish to Landlord such
additional plans, drawings, specifications and finish details as Landlord may
reasonably request to enable Landlord's architects and engineers to prepare
mechanical, electrical and plumbing plans and to prepare the Working Drawings,
including a final telephone layout and special electrical connection
requirements, if any. All plans, drawings, specifications and other details
describing the Work which have been or are hereafter furnished by or on behalf
of Tenant shall be subject to Landlord's approval, which Landlord agrees shall
not be unreasonably withheld. Landlord shall not be deemed to have acted
unreasonably if it withholds its approval of any plans, specifications, drawings
or other details or of any Additional Work (as defined in Paragraph 7 below)
because, in Landlord's reasonable opinion, the work, as described in any such
item, or the Additional Work, as the case may be: (a) is likely to adversely
affect Building systems, the structure of the Building or the safety of the
Building and/or its occupants; (b) might impair Landlord's ability to furnish
services to Tenant or other tenants in the Building; (c) would increase the cost
of operating the Building; (d) would violate any governmental laws, rules or
ordinances (or interpretations thereof); (e) contains or uses hazardous or toxic
materials or substances; (f) would adversely affect the appearance of the
Building; (g) might adversely affect another tenant's premises; (h) is
prohibited by any ground lease affecting the Building or any mortgage, trust
deed or other instrument encumbering the Building; or (i) is likely to be
substantially delayed because of unavailability or shortage of labor or
materials necessary to perform such work or the difficulties or unusual nature
of such work. The foregoing reasons, however, shall not be the only reasons for
which Landlord may withhold its approval, whether or not such other reasons are
similar or dissimilar to the foregoing. Neither the approval by Landlord of the
Work or the Initial Plan or any other plans, drawings, specifications or other
items associated with the Work nor Landlord's performance, supervision or
monitoring of the Work shall constitute any warranty by Landlord to Tenant of
the adequacy of the design for Tenant's intended use of the Premises.

        2. Working Drawings. If necessary for the performance of the Work and
not included as part of the Initial Plan attached hereto, Landlord shall prepare
or cause to be prepared final working drawings and specifications for the Work
(the "Working Drawings") based on and consistent with the Initial Plan and the
other plans, drawings, specifications, finish details and other information
furnished by Tenant to Landlord and approved by Landlord pursuant to Paragraph 1
above. So long as the Working Drawings are consistent with the Initial Plan,
Tenant shall approve the Working Drawings within three (3) days after receipt of
same from Landlord by initialing and returning to Landlord each sheet of the
Working Drawings or by executing Landlord's approval form then in use, whichever
method of approval Landlord may designate.

        3. Performance of the Work; Allowance. Except as hereinafter provided to
the contrary, Landlord shall cause the performance of the Work (except as may be
stated or shown otherwise in the Working Drawings) building standard materials,
quantities and

                                    EXHIBIT B
                                       1
<PAGE>   36

procedures then in use by Landlord ("Building Standards"). Landlord shall pay
for a portion of the "Cost of the Work" (as defined below) in an amount not to
exceed $6,000.00 (the "Allowance"), and Tenant shall pay for the entire Cost of
the Work in excess of the Allowance. Tenant shall not be entitled to any credit,
abatement or payment from Landlord in the event that the amount of the Allowance
specified above exceeds the Cost of the Work. For purposes of this Agreement,
the term "Cost of the Work" shall mean and include any and all costs expenses of
the Work, including, without limitation, the cost of the Working Drawings and of
all labor (including overtime) and materials constituting the Work.

        4. Payment. Prior to commencing the Work, Landlord shall submit to
Tenant a written statement of the total Cost of the Work (which shall include
the amount of any overtime projected as necessary to substantially complete the
Work by the Commencement Date specified in the Lease) as then known by Landlord,
and such statement shall indicate the amount, if any, by which the total Cost of
the Work exceeds the Allowance (the "Excess Costs"). Tenant agrees, within three
(3) days after submission to it of such statement, to execute and deliver to
Landlord, in the form then in use by Landlord, an authorization to proceed with
the Work, and Tenant shall also then pay to Landlord an amount equal to the
Excess Costs. No Work shall be commenced until Tenant has fully complied with
the preceding provisions of this Paragraph 4. In the event, and each time, that
any change order by Tenant unknown field condition, delay caused by acts beyond
Landlord's control or other event or circumstance causes the Cost of the Work to
be increased after the time that Landlord delivers to Tenant the aforesaid
initial statement of the Cost of the Work, Landlord shall deliver to Tenant a
revised statement of the total Cost of the Work, indicating the revised
calculation of the Excess Costs, if any. Within three (3) days after submission
to Tenant of any such revised statement, Tenant shall pay to Landlord an amount
equal to the Excess Costs, as shown in such revised statement, less the amounts
previously paid by Tenant to Landlord on account of the Excess Costs, and
Landlord shall not be required to proceed further with the Work until Tenant has
paid such amount. Delays in the performance of the Work resulting from the
failure of Tenant to comply with the provisions of this Paragraph 4 shall be
deemed to be delays caused by Tenant.

        5. Substantial Completion. Landlord shall cause the Work to be
substantially completed on or before the scheduled date of commencement of the
term of the Lease as specified in Section 1.6 of the Lease, subject to delays
caused by strikes, lockouts, boycotts or other labor problems, casualties,
discontinuance of any utility or other service required for performance of the
Work, unavailability or shortages of materials or other problems in obtaining
materials necessary for performance of the Work or any other matter beyond the
control of Landlord (or beyond the control of Landlord's contractors or
subcontractors performing the Work) and also subject to "Tenant Delays" (as
defined and described in Paragraph 6 of this Work Letter). The Work shall be
deemed to be "substantially completed" for all purposes under this Work Letter
and the Lease if and when Landlord's architect issues a written certificate to
Landlord and Tenant, certifying that the Work has been substantially completed
(i.e., completed except for "punchlist" items listed in such architect's
certificate) in substantial compliance with the Working Drawings, or when Tenant
first takes occupancy of the Premises, whichever first occurs. If the Work is
not deemed to be substantially completed on or before the scheduled date of the
commencement of the term of the Lease as specified in Section 1.6 of the Lease,
(a) Landlord agrees to use reasonable efforts to complete the Work as soon as
practicable thereafter, (b) the Lease shall remain in full force and effect, (c)
Landlord shall not be deemed to be in breach or default or the Lease or this
Work Letter as a result thereof and Landlord shall have no liability to Tenant
as a result of any delay in occupancy (whether for damages, abatement of Rent or
otherwise), and (d) except in the event of Tenant Delays, and notwithstanding
anything contained in the Lease to the contrary, the Commencement Date of the
Lease Term as specified in Section 1.6 of the Lease shall be extended to the
date on which the Work is deemed to be substantially completed and the
Expiration Date of the Lease Term as specified in Section 1.7 of the Lease shall
be extended by an equal number of days. At the request of either Landlord or
Tenant in the event of such extensions in the commencement and expiration dates
of the term of the Lease, Tenant and Landlord shall execute and deliver an
amendment to the Lease reflecting such extensions. Landlord agrees to use
reasonable diligence to complete all punchlist work listed in the aforesaid
architect's certificate promptly after substantial completion.

        6. Tenant Delays. There shall be no extension of the scheduled
commencement or expiration date of the term of the Lease (as otherwise
permissibly extended under Paragraph 5 above) if the Work has not been
substantially completed on said scheduled


                                    EXHIBIT B
                                       2
<PAGE>   37

commencement date by reason of any delay attributable to Tenant ("Tenant
Delays"), including without limitation:

             (i) the failure of Tenant to furnish all or any plans, drawings,
specifications, finish details or the other information required under Paragraph
1 above on or before the date stated in Paragraph 1;

             (ii) the failure of Tenant to grant approval of the Working
Drawings within the time required under Paragraph 2 above;

             (iii) the failure of Tenant to comply with the requirements of
Paragraph 4 above;

             (iv) Tenant's requirements for special work or materials, finishes,
or installations other than the Building Standards or Tenant's requirement for
special construction staging or phasing;

             (v) the performance of any Additional Work (as defined in Paragraph
7 below) requested by Tenant or the performance of any work in the Premises by
any person, firm or corporation employed by or on behalf of Tenant, or any
failure to complete or delay in completion of such work; or

             (vi) any other act or omission of Tenant that causes a delay.

        7. Additional Work. Upon Tenant's request and submission by Tenant (at
Tenant's sole cost and expense) of the necessary information and/or plans and
specifications for work other than the Work described in the Working Drawings
("Additional Work") and the approval by Landlord of such Additional Work, which
approval Landlord agrees shall not be unreasonably withheld, Landlord shall
perform such Additional Work, at Tenant's sole cost and expense, subject,
however, to the following provisions of this Paragraph 7. Prior to commencing
any Additional Work requested by Tenant, Landlord shall submit to Tenant a
written statement of the cost of such Additional Work, which cost shall include
a fee payable to Landlord in the amount of 15% of the total cost of such
Additional Work as compensation to Landlord for monitoring the Additional Work
and for administration, overhead and field supervision associated with the
Additional Work. (such fee being hereinafter referred to as "Landlord's
Additional Compensation"), and, concurrently with such statement of cost,
Landlord shall also submit to Tenant a proposed tenant extra order (the "TEO")
for the Additional Work in the standard form then in use by Landlord. Tenant
shall execute and deliver to Landlord such TEO and shall pay to Landlord the
entire cost of the Additional Work, including Landlord's Additional Compensation
(as reflected in Landlord's statement of such cost), within five (5) days after
Landlord's submission of such statement and TEO to Tenant. If Tenant fails to
execute or deliver such TEO or pay the entire cost of such Additional Work
within such 5-day period, then Landlord shall not be obligated to do any of the
Additional Work and may proceed to do only the Work, as specified in the Working
Drawings.

        8. Charges and Fees. Tenant shall pay Landlord a construction
management/supervisory fee in an amount equal to twelve percent (12%) of the
direct cost of the materials and labor for the Work (and all change orders with
respect thereto) to defray Landlord's administrative and overhead expenses
incurred to review the Plans and coordinate with architects, engineers, general
contractors and, if necessary, the Tenant's on-site project manager regarding
the staging and progression of the Work.

        9. Tenant Access. Landlord, in Landlord's reasonable discretion and upon
request by Tenant, may grant to Tenant a license to have access to the Premises
prior to the date designated in the Lease for the commencement of the term of
the Lease to allow Tenant to do other work required by Tenant to make the
Premises ready for Tenant's use and occupancy (the "Tenant's Pre-Occupancy
Work"). It shall be a condition to the grant by Landlord and continued
effectiveness of such license that:

             (i) Tenant shall give to Landlord a written request to have such
access to the Premises not less than five (5) days prior to the date on which
such access will commence, which written request shall contain or shall be
accompanied by each of the following items, all in form and substance reasonably
acceptable to Landlord: (a) a detailed description of and schedule

                                    EXHIBIT B
                                       3
<PAGE>   38

for Tenant's Pre-Occupancy Work; (b) the names and addresses of all contractors,
subcontractors and material suppliers and all other representatives of Tenant
who or which will be entering the Premises on behalf of Tenant to perform
Tenant's Pre-Occupancy Work or will be supplying materials for such work, and
the approximate number of individuals, itemized by trade, who will be present in
the Premises; (c) copies of all contracts, subcontracts and material purchase
orders pertaining to Tenant's Pre-Occupancy Work; (d) copies of all plans and
specifications pertaining to Tenant's Pre-Occupancy Work; (e) copies of all
licenses and permits in connection with the performance of Tenant's
Pre-Occupancy Work; (f) certificates of insurance (in amounts satisfactory to
Landlord and with the parties identified in, or required by, the Lease named as
additional insureds) and instruments of indemnification against all claims,
costs, expenses, damages and liabilities which may arise in connection with
Tenant's Pre-Occupancy Work; and (g) assurances of the ability of Tenant to pay
for all of Tenant's Pre-Occupancy Work; and/or a letter of credit or other
security deemed appropriate by Landlord securing Tenant's lien-free completion
of Tenant's Pre-Occupancy Work.

             (ii) Such pre-term access by Tenant and its representatives shall
be subject to scheduling by Landlord.

             (iii) Tenant's employees, agents, contractors, workmen, mechanics,
suppliers and invitees shall work in harmony and not interfere with Landlord or
Landlord's agents in performing the Work and any Additional Work in the
Premises, Landlord's work in other premises and in common areas of the Building,
or the general operation of the Building. If at any time any such person
representing Tenant shall cause or threaten to cause such disharmony or
interference, including labor disharmony, and Tenant fails to immediately
institute and maintain such corrective actions as directed by Landlord, then
Landlord may withdraw such license upon twenty-four (24) hours' prior written
notice to Tenant.

                  (a) Any such entry into and occupancy of the Premises by
Tenant or any person or entity working for or on behalf of Tenant shall be
deemed to be subject to all of the terms, covenants, conditions and provisions
of the Lease, specifically including the provisions of Section IX thereof
(regarding Tenant's improvements and alterations to the Premises), and excluding
only the covenant to pay Rent. Landlord shall not be liable for any injury, loss
or damage which may occur to any of Tenant's Pre-Occupancy Work made in or about
the Premises or to property placed therein prior to the commencement of the term
of the Lease, the same being at Tenant's sole risk and liability. Tenant shall
be liable to Landlord for any damage to the Premises or to any portion of the
Work or Additional Work caused by Tenant or any of Tenant's employees, agents,
contractors, workmen or suppliers. In the event that the performance of Tenant's
Pre-Occupancy Work causes extra costs to Landlord or requires the use of
elevators during hours other than 7:00 a.m. to 6:00 p.m. on Monday through
Friday (excluding holidays) or of other Building services, Tenant shall
reimburse Landlord for such extra cost and/or shall pay Landlord for such
elevator service or other Building services at Landlord's standard rates then in
effect.

        10. Lease Provisions. The terms and provisions of the Lease, insofar as
they are applicable to this Work Letter, are hereby incorporated herein by
reference. All amounts payable by Tenant to Landlord hereunder shall be deemed
to be additional Rent under the Lease and, upon any default in the payment of
same, Landlord shall have all of the rights and remedies provided for in the
Lease.

        11. Miscellaneous.

             (i) This Work Letter shall be governed by the laws of the state of
California.

             (ii) This Work Letter may not be amended except by a written
instrument signed by the party or parties to be bound thereby.

             (iii) Any person signing this Work Letter on behalf of Tenant
warrants and represents he/she has authority to sign and deliver this Work
Letter and bind Tenant.

             (iv) Notices under this Work Letter shall be given in the same
manner as under the Lease.


                                    EXHIBIT B
                                       4
<PAGE>   39

             (v) The headings set forth herein are for convenience only.

             (vi) This Work Letter sets forth the entire agreement of Tenant and
Landlord regarding the Work.

             (vii) In the event that the final working drawings and
specifications are included as part of the Initial Plan attached hereto, or in
the event Landlord performs the Work without the necessity of preparing working
drawings and specifications, then whenever the term "Working Drawings" is used
in this Agreement, such term shall be deemed to refer to the Initial Plan and
all supplemental plans and specifications approved by Landlord.

             (viii) Lessor recommends that the Premises' HVAC systems and
distribution be re-engineered and rebalanced anytime modifications are made to
Lessee's Premises. In the event Lessee elects not to re-engineer and/or
rebalance the HVAC systems, then Lessee shall have deemed to have accepted the
HVAC in its current as-is condition at the date of execution of this document,
and should it be deemed necessary, at anytime during the Term, to modify the
distribution of the HVAC to the Premises, all costs associated shall be at
Lessee's sole cost and expense.

        12. Exculpation of Landlord and Seagate. Notwithstanding anything to the
contrary contained in this Lease or in any exhibits, Riders or addenda hereto
attached (collectively the "Lease Documents"), it is expressly understood and
agreed by and between the parties hereto that: (a) the recourse of Tenant or its
successors or assigns against Landlord with respect to the alleged breach by or
on the part of Landlord of any representation, warranty, covenant, undertaking
or agreement contained in any of the Lease Documents or otherwise arising out of
Tenant's use of the Premises or the Building (collectively, "Landlord's Lease
Undertaking") shall extend only to Landlord's interest in the real estate of
which the Premises demised under the Lease Documents are a part ("Landlord's
Real Estate") and not to any other assets of Landlord or its beneficiaries; and
(b) no personal liability or personal responsibility of any sort with respect to
any of Landlord's Lease Undertakings or any alleged breach thereof is assumed
by, or shall at any time be asserted or enforceable against, Landlord, OTR, an
Ohio general partnership, Seagate Properties, Inc., Seagate Realty Advisors, or
against any of their respective directors, officers, employees, agents,
constituent partners, beneficiaries, trustees or representatives. Tenant
acknowledges that this Lease is executed by certain general partners of OTR
and/or Seagate Realty Advisors, not individually but solely on behalf of, and as
the authorized nominee and agent for, the State Teachers Retirement Board of
Ohio, and Tenant and all persons dealing with Landlord waive any right to bring
a cause of action against the individuals executing this Lease on behalf of
Landlord and must look solely to the assets of State Teachers Retirement Board
of Ohio for the enforcement of any claim against Landlord.

        IN WITNESS WHEREOF, this Work Letter Agreement is executed as of the
aforementioned date.



LANDLORD:                              TENANT:

OTR, an Ohio general                   CHEMCONNECT, INC., A DELAWARE
partnership, as Nominee of The         CORPORATION
State Teachers Retirement
Board of Ohio, a statutory
organization created by the
laws of Ohio                           By:
                                          --------------------------------------
By: SEAGATE REALTY ADVISORS, A         Its:
    CALIFORNIA GENERAL                     -------------------------------------
    PARTNERSHIP, ITS DULY              Date:
    AUTHORIZED AGENT                        ------------------------------------

By:
   -----------------------------------
Its:
    ----------------------------------
Date:
     ---------------------------------


                                    EXHIBIT B
                                       5
<PAGE>   40

                                   SCHEDULE I

                             COPIES OF INITIAL PLAN

The Premises is located adjacent to Suite 250 in the west wing of the Building
and bounded by a public corridor to the north and east of the Premises. Please
see floor plan below:



                            [Diagram of Leased Space]



                                   SCHEDULE I
<PAGE>   41

                                    EXHIBIT C

                              RULES AND REGULATIONS

        1. The sidewalks, entrances, passages, courts, elevators, vestibules,
stairways, corridors or halls shall not be obstructed or used for any purpose
other than ingress and egress. The halls, passages, entrances, elevators,
stairways, balconies and roof are not for the use of the general public, and
Landlord shall in all cases retain the right to control or prevent access
thereto by all persons whose presence in the judgment of Landlord shall be
prejudicial to the safety, character, reputation or interests of Landlord and
its tenants, provided that nothing herein contained shall be to prevent such use
by persons with whom the tenant normally deals in the ordinary course of its
business unless such persons are engaged in illegal activities. No tenant and no
employees of any tenant shall go upon the roof of the Building without the
written consent of Landlord.

        2. No awnings or other projections shall be attached to the outside
walls or surfaces of the Building nor shall the interior or exterior of any
windows be coated without the prior written consent of Landlord. Except as
otherwise specifically approved by Landlord, all electrical ceiling fixtures
hung in offices or spaces within the Building must be fluorescent and of
quality, type, design and bulb color approved by Landlord. Tenant shall not
place anything or allow anything to be placed near the glass of any window,
door, partition or wall which may appear unsightly from outside the Premises.

        3. No sign, picture, plaque, advertisement, notice or other material
shall be exhibited, painted, inscribed or affixed by any tenant or any part of,
or so as to be seen from the outside of, the Premises or the Building without
the prior written consent of Landlord. In the event of the violation of the
foregoing by any tenant, Landlord may remove the same without any liability, and
may charge the expense incurred in such removal to the tenant violating this
rule. Interior signs on doors and the directory tablet shall be inscribed,
painted or affixed for each tenant by Landlord at the expense of such tenant,
and shall be of a size, color and style acceptable to Landlord.

        4. The toilets and wash basins and other plumbing fixtures shall not be
used for any purpose other than those for which they were constructed, and no
sweepings, rubbish, rags or other substances shall be thrown therein. All damage
resulting from any misuse of the fixtures shall be borne by the tenant who, or
whose servants, employees, agents, visitors or licensees, shall have caused the
same.

        5. No tenant or its officers, agents, employees or invitees shall mark,
paint, drill into, or in any way deface any part of the Premises or the
Building. No boring, cutting or stringing of wires or laying of linoleum or
other similar floor coverings shall be permitted except with the prior written
consent of Landlord and as Landlord may direct.

        6. No bicycles, vehicles or animals of any kind shall be brought into or
kept in or about the Premises and no cooking shall be done or permitted by any
tenant on the Premises except that microwave cooking in a UL-approved microwave
oven and the preparation of coffee, tea, hot chocolate and similar items for the
tenant and its employees and business visitors shall be permitted. Tenant shall
not cause or permit any unusual or objectionable odors to escape from the
Premises

        7. The Premises shall not be used for manufacturing or for the storage
of merchandise except as such storage may be incidental to the use of the
Premises for general office purposes. No tenant shall engage or pay any
employees on the Premises except those actually working for such tenant on the
Premises nor advertise for laborers giving an address at the Premises. The
Premises shall not be used for lodging or sleeping or for any immoral or illegal
Purposes.

        8. No tenant or its officers, agents, employees or invitees shall make,
or permit to be made any unseemly or disturbing noises, sounds or vibrations or
disturb or interfere with occupants of this or neighboring buildings or Premises
or those having business with them whether by the use of any musical instrument,
radio, phonograph, unusual noise, or in any other way.


                                    EXHIBIT C
                                       1
<PAGE>   42

        9. No tenant or its officers, agents, employees or invitees shall throw
anything out of doors, balconies or down the passageways.

        10. Tenant shall not maintain armed security in or about the Premises
nor possess any weapons, explosives, combustibles or other hazardous devices in
or about the Building and/or Premises.

        11. No tenant or its officers, agents, employees or invitees shall at
any time use, bring or keep upon the Premises any flammable, combustible,
explosive, foul or noxious fluid, chemical or substance, or do or permit
anything to be done in the leased Premises, or bring or keep anything therein,
which shall in any way increase the rate of fire insurance on the Building, or
on the property kept therein, or obstruct or interfere with the rights of other
tenants, or in any way injure or annoy them, or conflict with the regulations of
the Fire Department or the fire laws, or with any insurance policy upon the
Building, or any part thereof, or with any rules and ordinances established by
the Board of Health other governmental authority.

        12. No additional locks or bolts of any kind shall be placed upon any of
the doors or windows by any tenant, nor shall any changes be made in existing
locks or the mechanism thereof. Each tenant must, upon the termination of this
tenancy, restore to Landlord all keys of stores, offices, and toilet rooms,
either furnished to, or otherwise procured by, such tenant, and in the event of
the loss of any keys so furnished, such tenant shall pay to Landlord the cost of
replacing the same or of changing the lock or locks opened by such lost key if
Landlord shall deem it necessary to make such change.

        13. All removals, or the carrying in or out of any safes, freight,
furniture, or bulky matter of any description must take place during the hours
which Landlord may determine from time to time. The moving of safes or other or
bulky matter of any kind must be made upon previous notice to the manager of the
Building and under his or her supervision, and the persons employed by any
tenant for such work must be acceptable to Landlord. Landlord reserves the right
to inspect all safes, freight or other bulky articles to be brought into the
Building and to exclude from the Building all safes, freight or other bulky
articles which violate any of these Rules and Regulations or the Lease of which
these Rules and Regulations are a part. Landlord reserves the right to prohibit
or impose conditions upon the installation on the Premises of heavy objects
which might overload the building floors. Landlord will not be responsible for
loss of or damage to any safes, freight, bulky articles or other property from
any cause, and all damage done to the Building by moving or maintaining any such
safe or other property shall be repaired at the expense of the tenant.

        14. No tenant shall purchase or otherwise obtain for use in the Premises
water, ice, towel, vending machine, janitorial, maintenance or other like
services, or accept barbering or bootblacking services, except from persons
authorized by Landlord, and at hours and under regulations fixed by Landlord.

        15. Landlord shall have the right to prohibit any advertising by any
tenant which, in Landlord's opinion, tends to impair the reputation of the
Building or its desirability as an office building and upon written notice from
Landlord any tenant shall refrain from or discontinue such advertising.

        16. Landlord reserves the right to exclude from the Building between the
hours of 10:00 p m. and 7:00 a.m. and at all hours of Saturdays, Sundays and
legal holidays all persons who do not present a pass signed by Landlord.
Landlord shall furnish passes to persons for whom any tenant requests in
writing. Each tenant shall be responsible for all persons for whom he requests
passes and shall be liable to Landlord for all acts of such persons. Landlord
shall in no case be liable for damages for any error with regard to the
admission to or exclusion from the Building of any person. In the case of
invasion, mob, riot, public excitement or other commotion, Landlord reserves the
right to prevent access to the Building during the continuance of the same, by
the closing of the gates and doors or otherwise, for the safety of the tenants
and others and the protection of the Building and the property therein.

        17. Any outside contractor employed by any tenant shall, while in the
Building, be subject to the prior written approval of Landlord and subject to
the Rules and Regulations of the Building. Tenant shall be responsible for all
acts of such persons and


                                    EXHIBIT C
                                       2
<PAGE>   43

Landlord shall not be responsible for any loss or damage to property in the
Premises, however occurring.

        18. All doors opening onto public corridors shall be kept closed, except
when in use for ingress and egress, and left locked when not in use.

        19. The requirements of tenants will be attended to only upon
application to the Office of the Building.

        20. Canvassing, soliciting and peddling in the Building are prohibited
and each tenant shall cooperate to prevent the same.

        21. All office equipment of any electrical or mechanical nature shall be
placed by tenants in the Premises in settings approved by Landlord, to absorb or
prevent any vibration, noise or annoyance.

        22. No air conditioning unit or other similar apparatus shall be
installed or used by any tenant without the written consent of Landlord.

        23. There shall not be used in any space, or in the public halls of the
Building either by any tenant or others, any hand trucks except those equipped
with rubber tires and side guards.

        24. Landlord will direct electricians as to where and how telephone and
telegraph wires are to be introduced. No boring or cutting for wires or
stringing of wires will be allowed without written consent of Landlord. The
location of telephones, call boxes and other office equipment affixed to the
Premises shall be subject to the approval of Landlord. All such work shall be
effected pursuant to permits issued by all applicable governmental authorities
having jurisdiction.

        25. No vendor with the intent of selling such goods shall be allowed to
transport or carry beverages, food, food containers, etc., on any passenger
elevators. The transportation of such items shall be via the service elevators
in such manner as prescribed by Landlord.

        26. Tenants shall cooperate with Landlord in the conservation of energy
used in or about the Building, including without rotation, cooperating with
Landlord in obtaining maximum effectiveness of the cooling system by closing
drapes or other window coverings when the sun's rays fall directly on windows of
the Premises, and closing windows and doors to prevent heat loss. Tenant shall
not obstruct, alter, or in any way impair the efficient operation of Landlord's
heating, lighting, ventilating and air conditioning system and shall not place
bottles, machines, parcels, or any other articles on the induction unit
enclosure so as to interfere with air flow. In addition, Tenant shall not
obstruct, alter, or in any way impair the proper circulation and regular
maintenance and repair of the induction unit by placing furniture less than 18
inches from the induction unit. Tenant shall not tamper with or change the
setting of any thermostats or temperature control valves, and shall in general
use heat, gas, electricity, air conditioning equipment and heating equipment in
a manner compatible with sound energy conservation practices and standards.

        27. All parking ramps and areas, pedestrian walkways, plazas, and other
public areas forming a part of the Building shall be under the sole and absolute
control of Landlord with the exclusive right to regulate and control these
areas. Tenant agrees to conform to the rules and regulations that may be
established by Landlord for these areas from time to time.

        28. Landlord reserves the right to exclude or expel from the Building
any person who, in the judgment of Landlord, is intoxicated or under the
influence of liquor or drugs, or who shall in any manner do any act in violation
of any of the rules and regulations of the Building.

        29. Tenant and its employees, agents, subtenants, contractors and
invitees shall comply with all applicable "nonsmoking" ordinances and,
irrespective of such ordinances, shall not smoke or permit smoking of
cigarettes, cigars or pipes outside of Tenant's Premises (including plaza areas)
in any portions of the Building except areas specifically designated as


                                    EXHIBIT C
                                       3
<PAGE>   44

smoking areas by Landlord. If required by applicable ordinance, Tenant shall
provide smoking areas within Tenant's Premises.


                                    EXHIBIT C
                                       4
<PAGE>   45

                                    EXHIBIT E

                            TENANT ACCEPTANCE LETTER

September 3, 1999

CHEMCONNECT, Inc.
44 Montgomery Street, Suite 250
San Francisco, CA 94104

Re:     44 Montgomery Street, Suite 280

Dear Tenants:

Please sign below to consign that you accept the Premises as complete under that
certain Lease Agreement dated September 3, 1999 by and between OTR, an Ohio
general partnership, as Nominee for the State Teachers Retirement Board of Ohio,
a statutory organization created by the laws of Ohio, and, CHEMCONNECT, INC., a
Delaware corporation and that the Commencement Date is October 15, 1999 and the
expiration date is December 31, 2001.

                                     Sincerely,


                                     SEAGATE PROPERTIES, Inc.
                                     Managing Agent


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

Acknowledged and Agreed:             Its:
                                         --------------------------------------

Tenant:                              Date:
       ----------------------------       -------------------------------------

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

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


                                    EXHIBIT E