EXHIBIT 10.1

May 11, 2001

Equity Office Properties Trust
EOP Operating Limited Partnership
Senior Term Loan Facility
Commitment Letter

Equity Office Properties Trust
Two North Riverside Plaza
Suite 2100
Chicago, Illinois 60606
Attention: Richard Kincaid

Ladies and Gentlemen:

EOP Operating Limited Partnership, a Delaware limited partnership (the
Borrower) and Equity Office Properties Trust (the Guarantor) have requested
that Banc of America Securities, LLC, J.P. Morgan Securities Inc. and Salomon
Smith Barney Inc. (collectively, the Arrangers) jointly agree to structure and
arrange a senior term loan facility in an aggregate amount of up to
$1,000,000,000 (the Facility). The Arrangers are pleased to advise you that
they are willing to act as joint and exclusive co-advisors, co-lead arrangers
and co-book runners for the Facility. In addition, The Chase Manhattan Bank has
agreed to serve as exclusive syndication agent for the Facility (in such
capacity, the Syndication Agent), Bank of America, N.A. has agreed to serve as
exclusive administrative agent for the Facility (in such capacity, the
Administrative Agent) and Salomon Smith Barney Inc. has agreed to serve as
exclusive documentation agent for the Facility (in such capacity, the
Documentation Agent, and together with the Syndication Agent and the
Administrative Agent, the Agents).

Furthermore, the Syndication Agent, the Administrative Agent and
Citicorp Real Estate, Inc. (CRE, and together with the Syndication Agent and
the Administrative Agent, the Lead Lenders) and Dresdner Bank AG, New York
and Cayman Branches (Dresdner), Deutsche Bank AG (Deutsche Bank) and PNC
Bank, NA (PNC, and together with Dresdner and Deutsche Bank the Co-Lenders)
are pleased to advise you of the several commitment of each of the Lead Lenders
and Co-Lenders to provide up to the following amounts of the Facility upon the
terms and subject to the conditions set forth in this commitment letter (the
Commitment





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Letter) and in the Summary of Terms and Conditions attached hereto as Exhibit A
(the Term Sheet)(each, an Initial Commitment):

|                     |  |   |                | 
|-------------------- |  | - | -------------- | 
|Syndication Agent    |  | $ | 271,666,666.67 | 
|                    
|                    
|                    
|                    
|Administrative Agent |  | $ | 271,666,666.67 | 
|                    
|                    
|                    
|                    
|CRE                  |  | $ | 271,666,666.66 | 
|                    
|                    
|                    
|                    
|Dresdner Bank        |  | $ | 75,000,000.00  | 
|                    
|                    
|                    
|                    
|Deutsche Bank        |  | $ | 75,000,000.00  | 
|                    
|                    
|                    
|                    
|PNC                  |  | $ | 35,000,000.00  | 

In the event funds are advanced under the Facility and remain
outstanding for more than 120 days, the Arrangers shall have the right to
syndicate the Facility to financial institutions (collectively, with the Lead
Lenders and the Co-Lenders, the Lenders) as further described below, in each
case upon the terms and subject to the conditions set forth or referred to in
this Commitment Letter, the Term Sheet or the Fee Letter referred to below.

It is agreed that the Administrative Agent will act as the sole and
exclusive administrative agent, that the Documentation Agent will act as sole
and exclusive documentation agent, that the Syndication Agent will act as sole
and exclusive syndication agent and that the Arrangers will act jointly as the
arrangers for the Facility, and each will, in such capacities, perform the
duties and exercise the authority customarily performed and exercised by it in
such roles. The Borrower and the Guarantor agree that no other agents, co-agents
or arrangers will be appointed, no other titles will be awarded and no
compensation (other than that expressly contemplated by the Term Sheet and the
Fee Letter referred to below) will be paid in connection with the Facility
unless the Borrower, the Arrangers, the Agents and the Lead Lenders shall so
agree.

In the event the Arrangers commence syndication efforts the Borrower
and the Guarantor agree to actively assist the Arrangers in completing such
syndication as reasonably requested by the Arrangers. Such assistance shall
include (a) the Borrower and the Guarantor using commercially reasonable
efforts to ensure that the syndication efforts benefit materially from the
Borrowers and the Guarantors existing lending relationships; (b) the Borrower
and the Guarantor assisting in the preparation of a confidential information
memorandum and other marketing materials to be used in connection with the
syndication by providing the information described in the following paragraph;
and (c) the Borrower and the Guarantor making their senior management and
advisors available to participate, upon reason-

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able notice, in information meetings for potential syndicate members at such
times and places as the Arrangers may reasonably request.

The Arrangers will jointly manage all aspects of the syndication,
provided that decisions as to the selection of institutions to be approached and
when they will be approached, when their commitments will be accepted and which
institutions will participate, will be made by mutual agreement of the Arrangers
and the Borrower and the allocations of the commitments among the Lenders and
the amount and distribution of fees among the Lenders will be determined by the
Arrangers, the Agents and the Lead Lenders. The Arrangers will have no
responsibility other than to arrange the syndication. To assist the Arrangers in
their syndication efforts, the Borrower and the Guarantor agree promptly to
prepare and provide to the Arrangers all information with respect to the
Borrower and the Guarantor and the transactions contemplated hereby, including
all financial information and projections (the Projections), as the Arrangers
may reasonably request in connection with the arrangement and syndication of the
Facility, so long as disclosure by the Borrower, the Guarantor or any of their
subsidiaries, of such information would not result in a violation of, or expose
the Borrower, the Guarantor or their subsidiaries to any material liability
under, any applicable law, ordinance or regulation or any agreements with
unaffiliated third parties which are binding on the Borrower, the Guarantor or
any of their subsidiaries or on any property of any of them. The Borrower and
the Guarantor agree to use commercially reasonable efforts to obtain any
necessary consents or waivers under any such agreements to disclose such
information to the Arrangers, the Agents and the Lenders. The Borrower and the
Guarantor hereby represent and covenant that (a) all information other than the
Projections (the Information) that has been or will be made available to the
Arrangers by the Borrower, the Guarantor or any of their respective
representatives is or will be, when furnished, complete and correct in all
material respects and does not or will not, when furnished, contain any material
misstatement or omission of fact and (b) the Projections that have been or will
be made available to the Arrangers by the Borrower, the Guarantor or any of
their representatives have been or will be prepared in good faith based upon
assumptions believed to be reasonable at the time of preparation thereof. The
Borrower and the Guarantor agree to supplement the Information and Projections
on the 120th day following the funding of the Facility and from time to time
upon request of the Arrangers or the Agents from the date hereof until the
completion of any syndication of the Facility as contemplated by this Commitment
Letter so all Information are complete and correct in all material respects and
do not contain any material misstatements or omissions of fact. The Borrower and
the Guarantor understand that in arranging and syndicating the Facility we may
use and rely on the Information and Projections without independent verification
thereof.

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As consideration for the Lenders commitment hereunder and the
respective agreements of the Arrangers and the Agents to perform the services
described herein, the Borrower and the Guarantor agree, jointly and severally,
to pay to each of the Lenders the nonrefundable fees set forth in the Term Sheet
and in the Fee Letter dated the date hereof and delivered herewith (the Fee
Letter).

The commitment of the Lead Lenders and the Co-Lenders hereunder and the
respective agreements of the Arrangers and the Agents to perform the services
described herein are subject to (a) there not occurring or becoming known to us
any material adverse condition or material adverse change in or affecting the
business, operations, property, condition (financial or otherwise) or prospects
of the Borrower, the Guarantor and their respective subsidiaries, taken as a
whole since the latest audited financial statements delivered to the Arrangers,
(b) our completion of and satisfaction in all respects with a due diligence
investigation up until the execution of definitive documentation with respect to
the Facility with respect to the business, operations, property, condition
(financial or otherwise) or prospects of the Borrower, the Guarantor and their
respective subsidiaries, (c) our not becoming aware after the date hereof of any
information or other matter affecting the Borrower, the Guarantor or the
transactions contemplated hereby which is inconsistent in a material and adverse
manner with any such information or other matter disclosed to us prior to the
date hereof which inconsistency would have a material adverse effect on the
business, operations, property, condition (financial or otherwise) or prospects
of the Borrower, the Guarantor and their respective subsidiaries, taken as a
whole as shown in the latest audited financial statements delivered to the
Arrangers, (d) our satisfaction that prior to and during the syndication of the
Facility there shall be no competing offering, placement or arrangement of any
bank financing other than property-specific mortgage debt and property-specific
mezzanine debt not prohibited by the Existing Credit Agreement (as defined in
the Term Sheet) by or on behalf of the Borrower, the Guarantor or any affiliate
thereof and other than the assumption of (or advances under) that certain
$171,000,000.00 Master Construction Funding Facility with Mountain Ventures
Golden State, LLC, and other single-member limited liability companies, as
Borrower, First Union National Bank, as Senior Lender and Administrative Agent,
Spieker Properties #183, as Junior Lender, First Union Development Corporation,
as Equity Investor, and Spieker Properties, L.P., as Purchaser, unless otherwise
agreed by the Arrangers and the Agents, (e) the negotiation, execution and
delivery on or before June 15, 2001 of definitive documentation with respect to
the Facility satisfactory to the Lenders and their counsel and (f) the other
conditions set forth or referred to in the Term Sheet.

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The Term Sheet attached hereto is intended as an outline only and does
not purport to summarize all of the terms, conditions, covenants,
representations, warranties and other provisions which will be contained in
definitive financing agreements for the Facility. The commitment of each of the
Lenders is subject to the satisfaction of the conditions set forth in this
Commitment Letter and the Term Sheet and customary conditions for transactions
of this type. Subject to the provisions of this Commitment Letter, the
definitive financing agreements shall contain terms, conditions, representations
and warranties, financial and other covenants, events of default and remedies
consistent with the Term Sheet and otherwise satisfactory to the Arrangers, the
Agents and the Lenders.

The Borrower and the Guarantor agree, jointly and severally to indemnify
the Arrangers, the Agents, the Lenders and the respective affiliates and the
respective directors, officers, agents, advisors and employees of the foregoing
(each an Indemnitee) and hold each Indemnitee harmless from and against any
and all liabilities, losses, damages, costs and expenses of any kind, including,
without limitation, the reasonable fees and disbursements of counsel, which may
be incurred by such Indemnitee in connection with any investigative,
administrative or judicial proceeding that may at any time (including, without
limitation, at any time following termination or expiration of this Commitment
Letter) be asserted against any Indemnitee, as a result of, or arising out of,
or in any way related to or by reason of this Commitment Letter, or any of the
transactions contemplated by this Commitment Letter or the execution, delivery
or performance of this Commitment Letter, but excluding those liabilities,
losses, damages, costs and expenses (a) for which such Indemnitee has been
compensated pursuant to the terms of this Commitment Letter or the Fee Letter or
(b) incurred solely by reason of the gross negligence, willful misconduct, bad
faith or fraud of any Indemnitee as finally determined by a court of competent
jurisdiction or (c) owing by such Indemnitee to any third party based upon
contractual obligations of such Indemnitee owing to such third party which are
not expressly set forth in this Commitment Letter. In addition, the
indemnification set forth in this paragraph in favor of any director, officer,
agent, advisor or employee of any Arranger, Agent or Lender shall be solely in
their respective capacities as such director, officer, agent, advisor or
employee. The Borrowers and the Guarantors obligations under this paragraph
shall survive the termination or expiration of this Commitment Letter.

Except for liability of each Lender for damages incurred by the Borrower
or the Guarantor to Spieker Properties, Inc. or Spieker Properties, L.P.
(collectively, Spieker Properties) in connection with a default by the
Borrower or the Guarantor under the Borrowers agreement with Spieker Properties
that results

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solely and directly from a breach of the obligations of such Lender under this
Commitment Letter (or directly in combination with such Lenders breach and a
breach of the obligations of another Lender under this Commitment Letter), no
Arranger, Agent or Lender shall be liable for any special, indirect,
consequential or punitive damages in connection with its activities related to
the Facility or for any special, indirect, consequential or punitive damages in
connection with this Commitment Letter.

This Commitment Letter shall not be assignable by the Borrower or the
Guarantor without the prior written consent of the Arrangers, the Agents and the
Lead Lenders (and any purported assignment without such consent shall be null
and void). The commitments of the Lenders and the obligations of the Arrangers
and the Agents set forth in this Commitment Letter are intended to be solely for
the benefit of the Borrower and the Guarantor and are not intended to confer any
benefits upon, or create any rights in favor of, any person other than the
Borrower and the Guarantor. This Commitment Letter may not be amended or waived
except by an instrument in writing signed by the Borrower, the Guarantor, the
Arrangers, the Agents and the Lenders. This Commitment Letter may be executed in
any number of counter-parts, each of which shall be an original, and all of
which, when taken together, shall constitute one agreement. Delivery of an
executed signature page of this Commitment Letter by facsimile transmission
shall be effective as delivery of manually executed counterpart hereof. This
Commitment Letter and the Fee Letter are the only agreements that have been
entered into among the Borrower, the Guarantor, the Arrangers, the Agents and
the Lenders with respect to the Facility and set forth the entire understanding
of the parties with respect thereto. This Commitment Letter shall be governed
by, and construed in accordance with, the laws of the State of New York.

Neither this Commitment Letter, the Term Sheet, the Fee Letter nor any
of the terms or substance thereof shall be disclosed, directly or indirectly, by
the Borrower, the Guarantor or their respective affiliates to any other person,
other than (i) to the respective directors, offices, employees, attorneys and
auditors of the Borrower and the Guarantor on a confidential, need-to-know
basis, (ii) such disclosure as may be compelled in a judicial or administrative
proceeding or as otherwise required by applicable law, (iii) to the rating
agencies, (iv) as may be required pursuant to the provisions of any agreement to
which Borrower, Guarantor or such affiliate is a party, (v) as may be required
in connection with Borrowers, Guarantors or such affiliates financial
statements, and (vi) in response to a query with respect to this Commitment
Letter, the Fee Letter or the terms or substance thereof.

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The Borrower and the Guarantor each acknowledge that the Arrangers, the
Agents and the Lenders may be providing debt financing, equity capital or other
services (including financial advisory services) to other companies in respect
of which the Borrower or the Guarantor may have conflicting interests regarding
the transactions described herein and otherwise. None of the Arrangers, the
Agents, the Lead Lenders or the Co-Lenders will use confidential information
obtained from the Borrower or the Guarantor by virtue of the transactions
contemplated by this Commitment Letter or their other relationships with the Borrower or the Guarantor
in connection with the performance by the Arrangers, the Agents, the Lead
Lenders or the Co-Lenders of services for other companies, and none of the
Arrangers, the Agents, the Lead Lenders or the Co-Lenders will furnish any such
information to other companies. The Borrower and the Guarantor also acknowledge
that the Arrangers, the Agents, the Lead Lenders and the Co-Lenders have no
obligation to use in connection with the transactions contemplated by this
Commitment Letter, or to furnish to the Borrower or the Guarantor, confidential
information obtained from other companies.

The compensation, reimbursement, indemnification, confidentiality,
syndication and market flex provisions contained herein and in the Fee Letter
shall remain in full force and effect regardless of whether definitive financing
documentation shall be executed and delivered and, with respect to
reimbursement, indemnification and confidentiality, notwithstanding the
termination of this Commitment Letter or commitments and respective agreements
of the Arrangers, the Agents and the Lenders hereunder.

If the foregoing correctly sets forth our agreement, please indicate the
Borrower and the Guarantors acceptance of the terms hereof and of the Term
Sheet and the Fee Letter by returning to us executed counterparts hereof and of
the Fee Letter not later than 5:00 p.m., New York City time, on May 15, 2001.
The commitments and respective agreements of the Arrangers, the Agents, the
Lead Lenders and the Co-Lenders herein will expire at such time in the event the
Administrative Agent has not received such executed counterparts in accordance
with the immediately preceding sentence.

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The Arrangers, the Agents, the Lead Lenders and the Co-Lenders are pleased to
have been given the opportunity to assist you in connection with this important
financing.



| | Very truly yours,
| | -----------------



| | Arrangers
| | ---------



| | BANC OF AMERICA SECURITIES, LLC
| | -------------------------------



| | By:/s/ PATRICK TROWBRIDGE
     Name: Patrick Trowbridge
     Title: Vice President
| | ----------------------------------------------------------------------------------



| | J.P. MORGAN SECURITIES INC.
| | ---------------------------



| | By:/s/ JOHN PERKINS
     Name: John Perkins
     Title: Vice President
| | ----------------------------------------------------------------------



| | SALOMON SMITH BARNEY INC.
| | -------------------------



| | By:/s/ KENT E. JEWETT
     Name: Kent E. Jewett
     Title: Managing Director
| | -----------------------------------------------------------------------------





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| | Agents
| | ------



| | BANK OF AMERICA, N.A.
| | ---------------------



| | By:/s/ PATRICK TROWBRIDGE
     Name: Patrick Trowbridge
     Title: Vice President
| | ----------------------------------------------------------------------------------



| | THE CHASE MANHATTAN BANK
| | ------------------------



| | By:/s/ MARC E. COSTANTINO
     Name: Marc E. Costantino
     Title: Vice President
| | ----------------------------------------------------------------------------------



| | SALOMON SMITH BARNEY INC.
| | -------------------------



| | By:/s/ KENT E. JEWETT
     Name: Kent E. Jewett
     Title: Managing Director
| | -----------------------------------------------------------------------------





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| | Lead Lenders
| | ------------



| | BANK OF AMERICA, N.A.
| | ---------------------



| | By:/s/ PATRICK TROWBRIDGE
     Name: Patrick Trowbridge
     Title: Vice President
| | ----------------------------------------------------------------------------------



| | THE CHASE MANHATTAN BANK
| | ------------------------



| | By:/s/ MARC E. COSTANTINO
     Name: Marc E. Costantino
     Title: Vice President
| | ----------------------------------------------------------------------------------



| | CITICORP REAL ESTATE, INC.
| | --------------------------



| | By:/s/ DAVID BOUTON
     Name: David Bouton
     Title: Director
| | ----------------------------------------------------------------





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| | Co-Lenders
| | ----------



| | DRESDNER BANK AG, NEW YORK
AND CAYMAN BRANCHES
| | ----------------------------------------------



| | By:_______________________________
     Name:
     Title:
| | ---------------------------------------------------------



| | DEUTSCHE BANK AG
| | ----------------



| | By:_______________________________
     Name:
     Title:
| | ---------------------------------------------------------



| | PNC BANK, NA
| | ------------



| | By:_______________________________
     Name:
     Title:
| | ---------------------------------------------------------





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Accepted and agreed to as of
the date first written above by:



|EQUITY OFFICE PROPERTIES TRUST
|------------------------------



|By:/s/ MAUREEN FEAR
     Name: Maureen Fear
     Title: Senior Vice President, Treasurer
|----------------------------------------------------------------------------------------



|EOP OPERATING LIMITED PARTNERSHIP
By:     Equity Office Properties Trust,
          its general partner
|-------------------------------------------------------------------------------------------------------



| | By:/s/ MAUREEN FEAR
     Name: Maureen Fear
     Title: Senior Vice President, Treasurer
| | ----------------------------------------------------------------------------------------