<PAGE>
                                                                   EXHIBIT 10.12

                                    SUBLEASE

          This Sublease is made as of July 30, 2004 ("SUBLEASE"), by and between
DEWEY BALLANTINE LLP, a New York limited liability partnership ("SUBLANDLORD"),
and THOMAS WEISEL PARTNERS GROUP LLC, a Delaware limited liability company
("SUBTENANT").

                                   WITNESSETH:

          WHEREAS, pursuant to that certain University Circle Office Lease dated
as of December 30, 2002, as amended by Amendment No.1 to University Circle
Office Lease dated as of February 1, 2003, and Amendment No.2 to University
Circle Office Lease dated as of July 1, 2003 (as so amended, the "MASTER
LEASE"), Sublandlord is leasing from University Circle Investors, LLC, a
Delaware limited liability company ("MASTER LANDLORD"), certain premises located
on the fifth and sixth floors of 1950 University Avenue, East Palo Alto,
California (as more fully described in the Master Lease, the "MASTER PREMISES");
and

          WHEREAS, Subtenant desires to sublease from Sublandlord, and
Sublandlord desires to lease to Subtenant, upon the terms and conditions of this
Sublease, that portion of the Premises located on the fifth floor, which the
parties agree has an area equal to 6,269 rentable square feet ("RSF") and the
boundaries of which are approximately depicted by cross-hatch marks on the Floor
Plan attached hereto as Exhibit A (such portion is the "SPACE").

          NOW, THEREFORE, in consideration of the mutual covenants set forth
herein, and other good and valuable consideration, the receipt and sufficiency
of which are hereby acknowledged, Sublandlord and Subtenant agree as follows:

               1. Master Lease. A copy of the Master Lease is attached hereto as
Exhibit C. Except as otherwise set forth to the contrary in this Sublease, the
terms of the Master Lease are hereby incorporated herein as if fully set forth
in this Sublease. All initially capitalized terms used herein without definition
are being used as defined in the Master Lease.

               2. Sublease. Sublandlord hereby leases to Subtenant, and
Subtenant hereby leases from Sublandlord, the Space, upon the terms and
conditions of this Sublease.

               3. Term. The term of this Sublease (the "TERM") shall commence on
the date (the "COMMENCEMENT DATE") that is the earlier to occur of:

                    (i) the date Subtenant opens for, or otherwise conducts,
business on or from any portion of the Space, and

                    (ii) the date that is the later to occur of: (a) September
1, 2004, and (b) the earliest date on which the following conditions have been
satisfied: (x) this Sublease has been signed and delivered by Sublandlord and
Subtenant, (y) the Master Landlord's consent to this Sublease has been obtained
as contemplated by Paragraph 18 of this Sublease, and (z) the Sublandlord Work
(as defined below) is Substantially Complete(as defined below).


                                        1
<PAGE>
Unless earlier terminated under any provision of the Master Lease or this
Sublease, the Term shall expire at midnight on the date which is one day
preceding the fifth annual anniversary of the Commencement Date. Promptly after
written request by Sublandlord, the parties shall execute and deliver a
verification memorandum which confirms the Commencement Date and the expiration
date of the initial Term.

                         (a) Early Entry. Notwithstanding that the Commencement
Date may not have yet occurred, Subtenant shall, from and after the date the
Master Landlord's consent to this Sublease has been obtained as contemplated by
Paragraph 18 of this Sublease, have the right to enter the Space solely for the
purpose of installing furniture, trade fixtures and equipment. Such early entry
and use shall be subject to all of the terms of this Sublease other than the
obligation to pay Base Rental (as hereinafter defined).

                         (b) Sublandlord shall use good faith efforts to
endeavor to complete the Sublandlord Work (as defined below) by September 15,
2004. Sublandlord shall have no liability to Subtenant of any kind whatsoever by
Sublandlord's failure to Substantially Complete the Sublandlord Work by
September 15, 2004; provided, however, that should Sublandlord fail for any
reason to Substantially Complete the Sublandlord Work by October 15, 2004 (as
such date is and shall be subject to extension for (x) the time it takes to
obtain Master Landlord's consent under paragraph 18 hereof, the "OUTSIDE
COMPLETION DATE"), then Subtenant shall, as Subtenant's sole remedy hereunder,
at law or in equity with respect to such failure, have the right to terminate
this Sublease by giving written notice of termination to Sublandlord before the
earlier to occur of (a) ten (10) business days after the Outside Completion
Date, and (b) the date Sublandlord actually delivers the Space to Subtenant with
the Sublandlord Work substantially completed. Upon such termination, neither
party shall have any further rights or obligations hereunder (except for any
obligations that are expressly provided hereunder to survive the termination of
this Sublease) and Sublandlord promptly shall refund to Subtenant all sums paid
by Subtenant to Sublandlord in connection with its execution hereof.
"Sublandlord Work" means those improvements described on Exhibit B hereto, as
more particularly described pursuant to plans and specifications that have been
approved by Sublandlord and Subtenant prior to the date hereof. The parties
agree that the costs of completing the Sublandlord Work (up to a maximum of
$38,423.00) shall be initially advanced by Sublandlord, but shall be subject to
reimbursement (together with interest charged by Sublandlord)through Subtenant's
payment of the Amortized TI Rent (as defined below). All costs to complete the
Sublandlord Work as a result of change orders initiated by Subtenant and that
result in a cost in excess of $38,423.00 shall be paid by Subtenant no later
than ten (10) business days after demand from Sublandlord. After the Sublandlord
Work has been Substantially Completed, Sublandlord shall use commercially
reasonable efforts to complete any "punchlist" items within thirty (30) days
thereafter.

               4. Rent. From the Commencement Date until the end of the Term,
Subtenant shall pay base rental ("BASE RENTAL") monthly in advance, without
notice, demand or setoff, on the first day of each and every calendar month
during the Term according to following schedule:

<TABLE>
<CAPTION>
       PERIOD OF TERM            BASE RENTAL RATE     MONTHLY RENT
       --------------            ----------------     ------------
<S>                            <C>                    <C>
Commencement Date - Month 12   $ 3.10 per RSF/month    $19,433.90
     Month 13 - Month 24       $3.193 per RSF/month    $20,016.92
</TABLE>


                                        2
<PAGE>
<TABLE>
<S>                            <C>                    <C>
     Month 25 - Month 36       $3.289 per RSF/month    $20,618.74
     Month 37 - Month 48       $3.388 per RSF/month    $21,239.37
     Month 49 - Month 60       $3.489 per RSF/month    $21,872.54
</TABLE>

In addition to Base Rental, Subtenant shall pay additional rental in the amount
of $752.28 per month (the "AMORTIZED TI RENT") monthly in advance, without
notice, demand or setoff, on the first day of each and every calendar month
during the Term.

Nothing in this paragraph 4, however, shall limit or affect Subtenant's
obligation to pay any amounts (other than Base Rental and Amortized TI Rent and
any payments pursuant to paragraph 5(a) below) which are due and payable by
Subtenant under this Sublease or the Master Lease as incorporated hereby. All
payments of Base Rental, Amortized TI Rent and all other sums and charges
payable by Subtenant pursuant to this Sublease, including, without limitation,
the sums payable pursuant to paragraph 5(a) below (collectively, "RENT"), shall
be sent to the address of Sublandlord provided in paragraph 15 below.

               5. Pass-Through Expenses; Nonstandard Utilities.

                    (a) Subtenant be responsible for, and shall pay to
Sublandlord in accordance with the other provisions of this paragraph 5, an
amount equal to 11.11% of the aggregate amount payable by Sublandlord under the
Master Lease for Sublandlord's share of Property Taxes and Operating Expenses
with respect to the Term. Sublandlord shall provide Subtenant with copies of all
statements received by Sublandlord from Master Landlord with respect to the
payment of Property Taxes and Operating Expenses under the Master Lease promptly
following Sublandlord's receipt thereof. Within thirty (30) days following
Sublandlord's receipt from Master Landlord of the final reconciliation of the
annual Property Taxes and Operating Expenses payable by Sublandlord pursuant to
the Master Lease for each year during the Term, Sublandlord and Subtenant shall
likewise reconcile the additional rental payable by Subtenant pursuant to this
paragraph 5 (i.e., Subtenant shall pay Subtenant's proportionate share of any
payment required to be made by Sublandlord to Master Landlord, or if a refund is
due Sublandlord from Master Landlord, Sublandlord shall refund or provide a
credit in the amount of Subtenant's proportionate share of Sublandlord's refund
against Base Rental next payable hereunder, as applicable). In any event, all
sums payable by Subtenant under this paragraph 5 shall be paid by Subtenant to
Sublandlord in accordance with Section 4(d) of the Master Lease to the extent
not inconsistent with the provisions of this paragraph 5, or, at the election of
Sublandlord, within ten (10) days after Subtenant's receipt of Sublandlord's
invoice therefor.

                    (b) Subtenant shall be responsible for the payment of all
cost recovery charges imposed on Sublandlord by Master Landlord pursuant to
Section 7(a) of the Master Lease as a result of any (i) utilities consumed by
Subtenant during Non-Service Hours or otherwise outside of Normal Office Hours,
(ii) labor or other direct costs incurred by Master Landlord for providing
utilities during Non-Service Hours or otherwise outside of Normal Office Hours,
and (iii) utilities consumed by Subtenant's auxiliary cooling unit in its Server
Room. Subtenant shall be responsible for providing and paying for all utilities
and services to the Space other than those utilities that Master Landlord is
required to provide pursuant to Section 7(a) of the Master Lease.


                                        3
<PAGE>
               6. Intentionally Deleted.

               7. Alterations. All tenant improvements and other alterations
desired by Subtenant for the Space shall be subject to the prior written
approval of Sublandlord, which shall not be unreasonably withheld and delayed,
and the prior written approval of Master Landlord. Subject to the foregoing,
Subtenant shall have the right to construct and install leasehold improvements
and other alterations desired by Subtenant in the Space in accordance with, and
subject to the limitations and conditions set forth in, this Sublease and the
Master Lease. Subtenant acknowledges that it is not entitled to receive any
tenant improvement allowance or similar sum under the Master Lease or this
Sublease.

               8. Parking. Effective as of the Commencement Date, Sublandlord
hereby assigns to Subtenant for the Term all of Sublandlord's right to use, at
no additional rent, twenty-one (21) parking spaces located in the Common Area in
accordance with and subject to the terms of the Master Lease. Except as provided
for in the preceding sentence, Subtenant shall have no parking rights or
privileges.

               9. Condition of Space. Sublandlord agrees to deliver possession
of the Space to Subtenant on the Commencement Date in its then current
condition, i.e., "AS IS" and "WITH ALL FAULTS"; provided, however, that subject
to the terms of Paragraph 3 of this Sublease, Sublandlord represents that all
Substantially Completed Sublandlord Work will be in good and workmanlike
condition as of the date delivered to Subtenant. Sublandlord further represents
to Subtenant that, to Sublandlord's actual knowledge, the heating, ventilating
and air conditioning system, and the electrical, mechanical, plumbing, sewer,
and life safety systems serving the Space are in good working order as of the
date of this Sublease. Sublandlord and Subtenant each agree that this Sublease
(together with the Master Lease as incorporated hereby) constitutes the entire
agreement of the parties hereto regarding the Space and that Sublandlord has not
made and is not making any representations or warranties, nor have the parties
made any understandings of any kind, pertaining to this Sublease or the Space
other than as expressly set forth in this Sublease (without incorporation of the
terms of the Master Lease). SUBTENANT FURTHER ACKNOWLEDGES AND AGREES THAT,
EXCEPT FOR ANY REPRESENTATIONS AND WARRANTIES EXPRESSLY MADE BY SUBLANDLORD IN
THIS SUBLEASE, SUBLANDLORD DOES HEREBY DISCLAIM ANY AND ALL WARRANTIES, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THOSE OF FITNESS FOR A PARTICULAR
PURPOSE, WITH RESPECT TO THE SPACE AND/OR THE IMPROVEMENTS LOCATED OR TO BE
LOCATED THEREIN. Subtenant acknowledges that it has investigated the Space and
the physical condition thereof to the extent it would, in Subtenant's judgment,
affect or influence Subtenant's use of the Space and Subtenant's willingness to
enter into this Sublease. Except as expressly set forth in this Sublease,
Subtenant hereby agrees to accept possession of the Space "as is" and "with all
faults" (it being understood and agreed that Sublandlord is not and shall not be
required to perform work of any kind or nature in connection with the delivery
to Subtenant of possession to the Space except as provided in Paragraph 3 of
this Sublease with respect to the Sublandlord Work).

               10. Performance by Sublandlord; Status of Master Lease.

                    (a) Subtenant recognizes that Sublandlord is not in a
position to render or furnish the services set forth in the Master Lease, obtain
an agreement of non-disturbance or to perform certain other obligations which
are not within the control of


                                        4
<PAGE>
Sublandlord, such as, without limitation, maintenance, repairs and replacements
by Master Landlord to the Space, compliance with laws, and restoration of the
Space after casualty or condemnation (collectively, the "MASTER LANDLORD
SERVICES"). Therefore, despite anything that may be construed to the contrary in
this Sublease or the Master Lease, Subtenant agrees that Sublandlord's sole
obligation with respect to the Master Landlord Services shall be to use
commercially reasonable good faith efforts, at the request of Subtenant, to
enforce Sublandlord's rights and remedies under the Master Lease for the purpose
of obtaining performance by Master Landlord of the Master Landlord Services (the
"ENFORCEMENT OBLIGATION"). Prior to making such request upon Sublandlord,
Subtenant shall diligently and in good faith endeavor to resolve with Master
Landlord any dispute or non-performance regarding Master Landlord Services (it
being acknowledged by Subtenant that it shall look first and only to Master
Landlord to furnish Master Landlord Services). Subtenant acknowledges that
Sublandlord shall have no obligation to provide any services to Subtenant, or to
perform any repair or maintenance of the Space. To the extent the Master Lease
obligates Master Landlord to provide such services or perform such work, such
obligation shall remain exclusively with Master Landlord, and shall not become
the obligation of Sublandlord. In any event, Subtenant will not have any claim
against Sublandlord based on the Master Landlord's failure or refusal to comply
with any of the provisions of the Master Lease unless that failure or refusal is
a result of Sublandlord's default under the Master Lease or Sublandlord's
default hereunder with respect to the Enforcement Obligation. So long as
Sublandlord materially performs its Enforcement Obligation, then, despite Master
Landlord's failure or refusal to comply with any of those provisions of the
Master Lease, this Sublease will remain in full force and effect and Subtenant
will pay the Base Rental and all other rent, sums and charges provided for in
this Sublease without any abatement, deduction or setoff; provided, however that
to the extent Sublandlord actually receives an abatement, deduction or setoff of
Base Rental or such other rent, sums and charges under the Master Lease, then
Subtenant shall receive an abatement on its rental obligations in the same
proportion as the abatement received by Sublandlord (i.e., if Sublandlord
receives a 50% abatement for 10 days on its rental obligations under the Master
Lease, then Subtenant shall receive a 50% abatement for 10 days on its rental
obligations hereunder). Notwithstanding the foregoing, Subtenant shall not be
entitled to any abatement on its obligation to pay the Amortized TI Rent.

                    (b) Prior to taking any action with respect to the Space
that would require the Sublandlord to obtain the Master Landlord's approval
under the Master Lease, Subtenant must first obtain approval from both the
Sublandlord (which approval Subtenant agrees is further contingent upon receipt
of the Master Landlord's approval).

                    (c) To the extent not inconsistent with the terms of this
Sublease, Subtenant agrees to perform all of the covenants, agreements, terms,
provisions, and conditions of the Master Lease, as though Subtenant was the
tenant under the Master Lease (including, without limitation, all use
restrictions, repair and maintenance obligations, indemnity provisions,
insurance requirements, surrender provisions, and interest and late charge
provisions), but in no event will Subtenant have any obligation to remove any
Sublandlord Work or restore improvements removed in connection with the
installation of Sublandlord Work. Subtenant shall not violate any provisions of
the Master Lease. Wherever in the Master Lease the word "Tenant" is used, for
the purposes of this Sublease, the word "Subtenant" shall be substituted, and
wherever the word "Landlord" is used, for the purposes of this Sublease, the
word "Sublandlord" shall be substituted; and that upon the breach of any of said
terms, conditions or covenants of the Master Lease by Subtenant or upon the
failure of Subtenant to pay Rent payable under this Sublease or comply with any
of the provisions of this Sublease,


                                        5
<PAGE>
Sublandlord may (following the notice and cure periods set forth in the Master
Lease) exercise any and all rights and remedies available to Master Landlord. In
the event of any conflict between this Sublease and the Master Lease, as between
Sublandlord and Subtenant the terms of this Sublease shall control. Whenever the
provisions of the Master Lease require the written consent of "Landlord", said
provisions shall be construed to require the written consent of both Master
Landlord and Sublandlord.

                    (d) Notwithstanding the foregoing provisions of this
paragraph 10, the following provisions of the Master Lease hereby do not apply
to this Sublease: Sections 1(b) 1(c), and 1(d); Section 2; Section 3(a); Section
4(d)(2); Section 5(b); Sections 6(c)(ii) and 6(d); Section 7(a), Section 8(a);
Section 10 (but only to the extent of any restoration obligations on the part of
the landlord); Section 15, Section 16(b); Sections 19(c) and 19(d); Section 20;
Section 21; Section 24(e); Exhibit A; Exhibit C; Exhibit D, Amendment No. 1 and
Amendment No. 2.

                    (e) Sublandlord agrees to perform its obligations under this
Sublease and its obligations under the Master Lease to the extent not made the
obligations of Subtenant hereunder. Sublandlord shall deliver to Subtenant a
copy of each notice of default received by Sublandlord from Master Landlord
pursuant to the Master Lease within five (5) business days after Sublandlord's
receipt thereof.

               11. Insurance. Sublandlord shall not be required to obtain and
maintain any insurance required of Master Landlord under the Master Lease.
Subtenant agrees to name both Master Landlord and Sublandlord as additional
insureds under the insurance policies which Subtenant is required to obtain and
maintain under the Master Lease.

               12. Signage. Subject to Master Landlord's consent and the
satisfaction of any applicable terms and conditions set forth in the Master
Lease, Subtenant shall have the right to, at Subtenant's cost and expense, (i)
display Subtenant's company name on the fifth (5th) floor sign directory, and
(ii) display Subtenant's company name as part of the directory for the building
in which the Space is located.

               13. Assignment and Subletting. Subtenant shall not assign,
mortgage, encumber or otherwise transfer this Sublease, nor sublease all or any
part of the Space, without in each case first obtaining the prior written
consent of (i) Sublandlord, which shall not be unreasonably withheld or delayed,
and (ii) Master Landlord. No later than 30 days prior to any proposed assignment
or sublease, Subtenant shall submit to Sublandlord such information as may be
reasonably required by Sublandlord with respect to the proposed assignee or
sublessee (collectively, the "TRANSFER INFORMATION"). In any event, no
assignment, subletting or other transfer shall relieve Subtenant of any
liability under this Sublease. Consent to any such assignment, subletting or
transfer shall not operate as a waiver of the necessity for consent to any
subsequent assignment, subletting or transfer. In connection with each request
for an assignment or subletting, Subtenant shall pay the actual and reasonable
out of pocket cost incurred by Sublandlord in connection with or as a result of
such assignment or subletting, including, without limitation, attorneys fees
(not to exceed $5,000), within fifteen (15) days after receipt of demand of
Sublandlord. In the event Subtenant proposes to assign or sublease all or any
portion of the Space for the remainder of the Term, then Sublandlord shall have
the right to recapture the Space and terminate this Sublease upon notice to
Subtenant given, if at all, within ten (10) business days of the date Subtenant
delivers the following: (a) all Transfer Information related to such


                                        6
<PAGE>
assignment or sublease, and (b) written request for Sublandlord's consent to
such assignment or sublease. With respect to all subleases, Subtenant will share
equally with Sublandlord any rents paid by such any sublessee that are in excess
of the Rents payable under this Sublease (after deduction for any costs
incurred by Subtenant directly related to such sublease). Sublandlord shall have
the right to assign, mortgage, encumber or otherwise transfer its interest in
this Sublease without the consent of Subtenant. Subject to the foregoing
provisions of this paragraph, this Sublease shall be binding upon and inure to
the benefit of Sublandlord and Sublandlord's successors and assigns, and
Subtenant and Subtenant's successors and permitted assigns.

               14. No Options. Subtenant acknowledges and agrees that it has no
rights to extend the Term. In any event and notwithstanding anything in this
Sublease that may be construed to the contrary, nothing herein shall be
construed as permitting Subtenant hereunder to exercise any extension or renewal
rights or to exercise any rights (whether rights of first refusal, first offer
or otherwise) to lease additional space or purchase the Space or expand the
Space, if any such rights exist, under the Master Lease (collectively,
"PREFERENTIAL RIGHTS"), and in no event shall Sublandlord be obligated to: (i)
extend the term of the Master Lease for any reason, and/or (ii) exercise any
such Preferential Rights.

               15. Notices. Any notice required or desired to be given under
this Sublease shall be in writing and made pursuant to Section 37 of the Master
Lease and shall be addressed to the address of the party to be served, at the
address provided in this section (or to such other addresses as any party hereto
may, from time to time, designate in writing to the others in accordance
herewith), as follows:

If to Sublandlord:       Dewey Ballantine LLP
                         1301 Avenue of the Americas
                         New York, New York 10019
                         Attn: Managing Partner

                         With a copy to:

                         Dewey Ballantine LLP
                         1301 Avenue of the Americas
                         New York, New York 10019
                         Attn: Tom VanBuskirk

If to Subtenant:         Thomas Weisel Partners Group
                         One Montgomery Street, 37th Floor
                         San Francisco, California 94104
                         Attention: Corporate Real Estate Department

If to Master Landlord:   To the address specified in the Master Lease.

          16. Broker's Fees. Sublandlord and Subtenant each represents and
warrants to the other that it has dealt with no broker or other intermediary in
connection with this transaction other than Cushman & Wakefield of California,
Inc., as Sublandlord's broker, and Roger Fields of Cornish & Carey, as
Subtenant's exclusive broker (collectively, the "DISCLOSED BROKERS").
Sublandlord agrees to pay, pursuant to a separate agreement between Sublandlord
and Disclosed


                                        7
<PAGE>
Brokers, any commission payable to Disclosed Brokers in connection herewith, and
shall indemnify, defend and hold harmless Subtenant with respect thereto.
Notwithstanding the foregoing, if any broker, finder or other intermediary other
than the Disclosed Brokers claims to be entitled to a fee or commission by
reason of having dealt with Sublandlord or Subtenant in connection with this
transaction, or having introduced the Space to Subtenant for lease, or having
been the inducing or procuring cause to this Sublease, the party with whom such
broker, finder or other intermediary claims to have dealt with shall indemnify,
defend and hold harmless the other party of and from any claim for commission or
other compensation by such broker, finder or other intermediary. The provisions
of this paragraph 16 shall survive the expiration of the Term hereof or any
earlier termination of this Sublease.

          17. Default By Sublandlord Under Master Lease; Casualty and
Condemnation.

               (a) In the event of a default by Sublandlord under the Master
Lease which results in termination of the Master Lease, this Sublease shall, at
the sole and absolute option and discretion of the Master Landlord, remain in
full force and effect as a direct lease between Master Landlord and Subtenant
upon and subject to all of the terms hereof, and the Subtenant shall attorn to
and recognize Master Landlord as Sublandlord hereunder and shall promptly upon
such Master Landlord's request, execute and deliver all instruments necessary or
appropriate to confirm such attornment and recognition. The Subtenant hereunder
hereby waives all rights under any present or future law or otherwise to elect,
by reason of the termination of the Master Lease, to terminate this Sublease or
surrender possession of the premises demised hereby. Subject to subparagraph (b)
below, for so long as Master Landlord is not in default under the Master Lease,
Sublandlord shall not voluntarily terminate the Master Lease during the Term
unless and until Master Landlord has agreed in writing to continue this Sublease
in full force and effect as a direct lease between Master Landlord and Subtenant
upon and subject to all of the terms, covenants and conditions of this Sublease
for the balance of the Term hereof. If Master Landlord so consents, Subtenant
shall attorn to and recognize Master Landlord as Landlord hereunder and shall
promptly upon such Master Landlord's request, execute and deliver all
instruments necessary or appropriate to confirm such attornment and recognition.

               (b) Nothing in this Sublease shall restrict or preclude
Sublandlord from exercising any right to terminate the Master Lease (i) by
reason of any default of Master Landlord thereunder, or (ii) pursuant to the
provisions of the Master Lease relating to fire or other casualty, or
condemnation

          18. Landlord's Consent. This Sublease is subject to and contingent
upon Master Landlord's execution and delivery of its written consent to this
Sublease on or before the date which is fifteen (15) business days after the
date hereof . In the event Master Landlord does not execute and deliver such
consent within such time, then either Sublandlord or Subtenant may terminate
this Sublease by giving the other party ten (10) days' prior written notice, in
which case this Sublease shall terminate on the day following the last day of
the ten (10)-day notice period (unless Master Landlord's consent is obtained
during such ten (10)-day period, in which case this Sublease shall remain in
full force and effect), neither party shall have any further rights or
obligations (hereunder except for any liability or obligation that is expressly
provided hereunder to survive the expiration of the Term hereof of or
termination of this Sublease), and Sublandlord shall return to Subtenant all
sums paid by Subtenant to Sublandlord in connection with Subtenant's execution
hereof.


                                        8
<PAGE>
          19. Miscellaneous Representations. Subtenant warrants and represents,
for the benefit of Sublandlord only, that (i) Subtenant is a duly organized and
existing limited liability company under the laws of the State of Delaware and
is authorized to transact business in the State of California; (ii) Subtenant
has full right and authority to execute, deliver and perform under this
Sublease; and (iii) the persons executing this Sublease were authorized to do
so. Sublandlord warrants and represents, for the benefit of Subtenant only, that
(i) Sublandlord is a duly organized and existing limited liability partnership
under the laws of the State of New York, and is authorized to transact business
in the State of California; (ii) Sublandlord has full right and authority to
execute, deliver and perform under this Sublease; (iii) the persons executing
this Sublease on behalf of Sublandlord were authorized to do so, and (iv) there
exists under the Master Lease no uncured default or event of default on the part
of Sublandlord or, to Sublandlord's actual knowledge, on the part of Master
Landlord, nor to Sublandlord's actual knowledge has there occurred any event
which, with the giving of notice or passage of time or both, would constitute
such a default or event of default.

20. Governing Law. This Sublease shall be governed by and construed in
accordance with the laws of the State of California. If any provision of this
Sublease is held to be or rendered unenforceable for any reason whatsoever, all
other provisions hereof shall remain in full force and effect.

          21. Entire Agreement. This Sublease sets forth all covenants,
agreements and understandings between Sublandlord and Subtenant with respect to
the specific subject matter hereof and there are no other covenants, conditions
or understandings, either written or oral, between the parties hereto except as
set forth in this Sublease. Subtenant is not a third party beneficiary of the
Master Lease.

          22. Counterparts. This Sublease may be executed in multiple
counterparts, and each counterpart when fully executed and delivered shall
constitute an original instrument, and all such multiple counterparts shall
constitute but one and the same instrument.

          23. Holdover. If Subtenant holds over in the Space after the
expiration of the term of this Sublease (or the termination of this Sublease)
without the prior written consent of Sublandlord and Master Landlord, Subtenant
shall be deemed to be occupying the Space as a tenant at sufferance at a daily
rental equal to one thirtieth (1/30th) of one hundred twenty five percent (125%)
of the Base Rental in effect during the last month of the Term, as may be
extended hereby, and otherwise subject to all the conditions, provisions and
obligations of this Sublease insofar as the same are applicable to a tenancy at
sufferance. In addition, Subtenant shall: (i) indemnify Sublandlord against all
costs or claims for damages Sublandlord may incur from Master Landlord by reason
of such holdover; and (ii) indemnify Sublandlord against all claims for damages
by any other tenant or person to whom Sublandlord may have leased all or any
part of the Space covered hereby and being held over by Subtenant from and after
the expiration of this Sublease; provided, however, that Sublandlord agrees to
promptly notify and inform Subtenant about any proposed leasing or other
occupancy transactions with respect to all or any part of the Space, whether
initiated by Master Landlord, Sublandlord or any other person. The inclusion of
this Section shall not be deemed Sublandlord's or Master Landlord's consent to
any holding over.


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<PAGE>
          24. Cure Right. If Subtenant shall at any time fail to make any
payment or perform any other obligation of Subtenant hereunder, then Sublandlord
shall have the right, but not the obligation, after the lesser of five (5)
business days' notice to Subtenant or the time within which Master Landlord may
act on Sublandlord's behalf under the Master Lease, or without notice to
Subtenant in the case of any emergency, and without waiving or releasing
Subtenant from any obligations of Subtenant hereunder, to make such payment or
perform such other obligation of Subtenant in such manner and to such extent as
Sublandlord shall deem necessary, and in exercising any such right, to pay any
incidental costs and expenses, employ attorneys and other professionals, and
incur and pay reasonable attorneys' fees and other costs reasonably required in
connection therewith. Subtenant shall pay to Sublandlord upon demand all sums so
paid by Sublandlord and all incidental costs and expenses of Sublandlord in
connection therewith, together with interest thereon at the interest rate
provided in Section 3(d) of the Master Lease.

          25. Access. Sublandlord reserves the right to enter the Space upon
reasonable advance notice to Subtenant (except that in case of emergency no
notice shall be necessary) in order to (i) inspect the Space and/or the
performance by Subtenant of the terms of this Sublease, and (ii) during the last
thirty (30) days of the Term, to perform Sublandlord's restoration obligations
under the Master Lease, if any. Except in case of an emergency, Subtenant shall
have the right to require that a representative of Subtenant be present during
Sublandlord's entry into the Space pursuant to this paragraph.

                            [Signatures on next page]


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<PAGE>
          IN WITNESS WHEREOF, the undersigned have executed this Sublease as of
the day and date first written above.

Sublandlord:

DEWEY BALLANTINE LLP,
a New York limited liability partnership


By: /s/ Richard Shutran
    ---------------------------------
Name: Richard Shutran
Title: Co-Managing Partner


Subtenant:

THOMAS WEISEL PARTNERS GROUP LLC,
a Delaware limited liability company


By: /s/ Robert West
    ---------------------------------
Name: Robert West
Title: Chief Financial Officer


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