Exhibit
4.1


FOURTH
SUPPLEMENTAL INDENTURE


This FOURTH SUPPLEMENTAL INDENTURE (this “Fourth
Supplemental Indenture”) is dated as of October 5, 2007, between
Archstone-Smith Operating Trust (the successor to Archstone
Communities Trust, Security Capital Pacific Trust and Property Trust of
America), a real
estate investment trust organized under the laws of the State of Maryland (the “Company”),
and U.S. Bank National Association, as trustee (as successor Trustee to
Morgan Guaranty Trust Company of New York and State Street Bank and Trust
Company) (the “Trustee”)
under the Indenture (as hereinafter defined).


WHEREAS, the Company (formerly known as Property Trust
of America), and the Trustee (as successor Trustee to Morgan Guaranty Trust
Company of New York and State Street Bank and Trust Company) are parties to an
Indenture, dated as of February 1, 1994, as amended and supplemented by the
First Supplemental Indenture (the “First Supplemental Indenture”) dated
as of February 2, 1994, the Second Supplemental Indenture, dated as of August
2, 2004 (the “Second Supplemental Indenture”), and the Third
Supplemental Indenture (the “Third Supplemental Indenture”) dated as of
July 14, 2006 (as amended and supplemented by the First Supplemental Indenture,
the Second Supplemental Indenture, and the Third Supplemental Indenture, the “Indenture”),
pursuant to which the Company issued its 4.00% Exchangeable Senior Notes due
2036 (the “Notes”);


WHEREAS, on May 28, 2007, the Company entered into
Agreement and Plan of Merger by and among Archstone-Smith Trust, a real estate investment trust formed under
the laws of the State of Maryland and sole trustee of the Company (“Archstone”),
River Holding, LP, River Acquisition (MD), LP and River Trust Acquisition (MD),
LLC (the “Operating Trust MergerSub”), as amended by Amendment No. 1 to Agreement and Plan of Merger, dated as
of August 5, 2007 (as so amended, the “Merger Agreement”),
pursuant to which, among other things, Archstone
will merge with and into Tishman Speyer Archstone-Smith Multifamily
Series I Trust (“Tishman Speyer”), an assignee of River Acquisition (MD), LP (the “Merger”), with Tishman
Speyer being the surviving entity;


WHEREAS, Section 8.06 of the Third Supplemental
Indenture provides that in the event of a merger of Archstone with another
person as a result of which Holders of Common
Shares shall be entitled to receive cash, securities or other property or
assets with respect to or in exchange for such Common Shares, then, the Company
shall execute with the Trustee a supplemental indenture providing for the
exchange and settlement of the Notes as set forth in the Third Supplemental
Indenture;


WHEREAS, the execution and delivery of this instrument
have been duly authorized and all conditions and requirements necessary to make
this instrument a valid and binding agreement have been duly performed and
complied with; and


WHEREAS, this Fourth Supplemental Indenture is being
executed and delivered concurrently with the effectiveness of the Merger.


NOW, THEREFORE, in consideration of the premises set
forth herein and for other good and valuable consideration, the receipt and
sufficiency of which are hereby 

















 


acknowledged, it is mutually covenanted and agreed,
for the equal and proportionate benefit of all Holders, as follows:


ARTICLE 1.                          EFFECT OF MERGER


Section 1.01.          In
accordance with Section 8.06 of the Third Supplemental Indenture, at and after
the effective time of the Merger, the right to exchange each $1,000 principal
amount of Notes will be changed to a right to exchange such Notes into an
amount of cash that a Holder immediately prior to the effective time of the
Merger of a number of Common Shares equal to the sum of (x) 15.7304, which
was the Exchange Rate immediately prior to the Merger, after adjustment
pursuant to Section 8.04(d) of the Third Supplemental Indenture, plus (y),
solely with respect to any Holder that delivers an exchange notice during the
period beginning on the date hereof and ending on the Fundamental Change
Repurchase Date, a number of Additional Shares equal to 1.7834 in accordance
with Section 8.01(g) of the Third Supplemental Indenture, would have been or
entitled to receive as a result of the Merger.


ARTICLE
2.                          MISCELLANEOUS


Section 2.01.          Capitalized
terms used herein and not defined herein have the meanings ascribed to such
terms in the Indenture.


Section 2.02.          This
Fourth Supplemental Indenture shall become effective as of the date hereof at
such time as executed counterparts of this Fourth Supplemental Indenture have
been delivered by each party hereto to the other party thereto.


Section 2.03.          On
the date hereof, the Indenture shall be supplemented and amended in accordance
herewith, and this Fourth Supplemental Indenture shall form part of the
Indenture for all purposes, and the Holder of every Note heretofore or
hereafter authenticated and delivered under the Indenture shall be bound
thereby.  The Trustee accepts the trusts
created by the Indenture, as amended and supplemented by this Fourth
Supplemental Indenture, and agrees to perform the same upon the terms and
conditions of the Indenture, as amended and supplemented by this Fourth
Supplemental Indenture.


Section 2.04.          This
Fourth Supplemental Indenture shall be deemed to be incorporated in, and made a
part of, the Indenture.  The Indenture, as
amended and supplemented by this Fourth Supplemental Indenture, shall be read,
taken and construed as one and the same instrument and all provisions in the
Indenture and the Notes shall remain in full force and effect in accordance
with the terms thereof and as amended and supplemented by this Fourth
Supplemental Indenture.


Section 2.05.          In
case any one or more of the provisions contained in this Fourth Supplemental
Indenture shall for any reason be held to be invalid, illegal or unenforceable
in any respect, such invalidity, illegality or unenforceability shall not
affect any other provisions of this Fourth Supplemental Indenture, but this
Fourth Supplemental Indenture shall be construed as if such invalid, illegal or
unenforceable provision had never been contained herein.


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Section 2.06.          The
parties may sign any number of copies of this Fourth Supplemental
Indenture.  Each signed copy shall be an
original, but all of them together represent the same agreement.


Section 2.07.          The
Trustee shall not be responsible in any manner whatsoever for or in respect of
the validity and sufficiency of this Fourth Supplemental Indenture or for or in
respect of the recitals contained herein, all of which are made solely by the
Company.


Section 2.08.          In
entering into this Fourth Supplemental Indenture, the Trustee shall be entitled
to the benefit of every provision of the Indenture and the Securities relating
to the conduct or affecting the liability of or affording protection to the
Trustee, whether or not elsewhere herein so provided.


Section 2.09.          All
covenants and agreements in this Fourth Supplemental Indenture by the Company
and the Trustee shall bind their respective successors and assigns.  Nothing in this Fourth Supplemental
Indenture, express or implied,  shall
give to any person, other than the parties hereto and their successors under
the Indenture and the Holders of the Notes, any benefit of any legal or
equitable right, remedy or claim under the Indenture.


Section 2.10.          This
Fourth Supplemental Indenture shall be governed by, and construed in accordance
with, the laws of the State of New York, without regard to principles of
conflicts of law.


 


[Signature page follows]


 


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IN WITNESS WHEREOF, the parties hereto have caused
this Fourth Supplemental Indenture to be duly executed as of the day and year
first above written.


 


	
   

  	
  ARCHSTONE-SMITH OPERATING TRUST

  
	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ Charles E. Mueller, Jr.

  
	
   

  	
  Name:

  	
  Charles E. Mueller, Jr.

  
	
   

  	
  Title:

  	
  Executive Vice President and 

  
	
   

  	
   

  	
  Chief Financial Officer

  
	
   

  	
   

  	
   

  
	
   

  	
  U.S. BANK NATIONAL ASSOCIATION,

  
	
   

  	
  as Trustee

  
	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ Thomas E. Tabor 

  
	
   

  	
  Name:

  	
  Thomas E. Tabor 

  
	
   

  	
  Title:

  	
  Vice President

  



 


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