EXHIBIT 99.6
              UNIT TWO CONTRACT ASSIGNMENT AND ASSUMPTION AGREEMENT


     This ASSIGNMENT AND ASSUMPTION OF CONTRACT OF SALE (this "ASSIGNMENT") is
made and entered into as of the 25th day of April 2001, by and among DAI-ICHI
LIFE INVESTMENT PROPERTIES, INC., a Delaware corporation (the "ASSIGNOR"),
BP/CGCENTER II LLC, a Delaware limited liability company ("ASSIGNEE"), and
CITIBANK, N.A., a national banking association ("SELLER").

                               W I T N E S S E T H

         WHEREAS, the premises described in EXHIBIT A, together with the
improvements erected thereon (collectively, "CITIGROUP CENTER") are subject to
condominium form of ownership pursuant to the terms of that certain Amended and
Restated Declaration of Condominium dated as of August 22, 2000 (the
"CONDOMINIUM DECLARATION");

         WHEREAS, Assignor, Seller and St. Peter's Lutheran Church of Manhattan
are the owners of the fee title interest in and to the condominium units in the
Citigroup Center created pursuant to the Condominium Declaration;

         WHEREAS, Seller is the fee owner of the premises described in EXHIBIT
B, together with the improvements erected thereon and referred to as "CITIGROUP
CENTER OFFICE UNIT TWO" in the Condominium Declaration (the "UNIT");

         WHEREAS, Seller, as Seller, and Assignor, as Purchaser, executed a
Contract of Sale, dated as of November 22, 2000 (which, together with all
modifications, amendments and assignments thereto or thereof, is hereinafter
referred to collectively as the "CONTRACT OF SALE"), a copy of which is attached
hereto as EXHIBIT C, pursuant to which Seller has agreed to sell its fee
interest in the Unit to Assignor, or Assignor's assignee, upon the terms and
conditions set forth therein;

         WHEREAS, Assignor and Assignee desire that, among other things,
Assignee shall acquire from Assignor Assignor's right to purchase the Unit
pursuant to and under the Contract of Sale, and that Assignee shall assume
certain liabilities and obligations from Assignor, including Assignor's
liabilities and obligations under the Contract of Sale;

         WHEREAS, in furtherance thereof, Assignor agreed, pursuant to that
certain Agreement to Enter Into Unit Two Contract Assignment and Assumption
Agreement dated as of February 6, 2001 between Assignor and Assignee, to assign
the Contract of Sale to Assignee, and Assignee agreed to accept the assignment
of the Contract of Sale from Assignor and to assume and be bound by all of the
terms, conditions, provisions, obligations, covenants and duties of Assignor
under the Contract of Sale from and after the date hereof upon and subject to
the terms of this Agreement;


         WHEREAS, Seller has agreed to enter into this Assignment for the sole
purposes of (a) agreeing to be bound by the provisions of SECTION 5 and (b)
consenting to this Assignment, as required pursuant to Section 20(a) of the
Contract of Sale; and

         WHEREAS, the parties hereto are desirous of setting forth their
respective rights and obligations with respect to the transactions contemplated
by this Assignment,

         NOW, THEREFORE, in consideration of the foregoing recitals which are
incorporated into the operative provisions of this Assignment by this reference,
mutual covenants and agreements herein contained and for other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged,
Assignor and Assignee hereby covenant and agree as follows:

1.   DEFINITIONS. Capitalized terms used in this Assignment without definition
     shall have the respective meanings ascribed to them in the Contract of
     Sale.

2.   ASSIGNMENT. Assignor hereby grants, assigns and transfers to Assignee, its
     successors and assigns, all of Assignor's right, title and interest in, to
     and under the Contract of Sale (except as expressly limited by the terms of
     this Assignment), and Assignee accepts from Assignor all of Assignor's
     right, title and interest in, to and under the Contract of Sale (except as
     expressly limited by the terms of this Assignment).

3.   ASSUMPTION OF OBLIGATIONS. Assignee hereby assumes and agrees to be bound
     by and to perform and fulfill all of the terms, conditions, provisions,
     obligations, covenants and duties required to be performed and fulfilled by
     Assignor under the Contract of Sale from and after the date of this
     Assignment as if Assignee was an original party thereto (except as
     expressly limited by the terms of this Assignment), including, without
     limitation, the obligation to make all payments due or payable under the
     Contract of Sale to be made by the Purchaser as they become due and
     payable.

4.   ASSIGNOR NOT RELIEVED OF ITS OBLIGATIONS. Notwithstanding the assumption by
     Assignee set forth in SECTION 2, nothing in this Assignment shall be deemed
     to relieve Assignor of any obligations it may have to Seller under the
     Contract of Sale.

5.   RETAINED RIGHTS OF ASSIGNOR. Assignor and Assignee hereby agree that,
     notwithstanding the other provisions of this Assignment, from and after the
     date hereof, (a) Assignor shall retain its obligations to pay any fees due
     to JLL pursuant to Section 5(a) of the Contract of Sale, (b) Assignor shall
     retain its rights under Section 6(h) of the Contract of Sale and Assignor
     and Assignee shall thereafter each have the right granted pursuant to
     Section 6(h) of the Contract of Sale to review the books and records of
     Seller, subject to the terms and conditions set forth therein, and (c)
     Seller's indemnification obligations under Sections 5(b) and 9(b) of the
     Contract of Sale shall run in favor of both Assignor and Assignee. Seller,
     by executing this Assignment below, hereby consents to the provisions of
     this SECTION 5 and agrees to be bound hereby.

                                       2


6.   ASSIGNMENT WITHOUT WARRANTY OR REPRESENTATION BY OR RECOURSE AGAINST
     ASSIGNOR. The assignment is made by Assignor without warranty or
     representation by, or recourse against, Assignor, except as to the validity
     of this Assignment and Assignor's authority to enter into it.

7.   SUCCESSORS AND ASSIGNS. This Assignment shall be binding on and inure to
     the benefit of the parties hereto, and their respective successors and
     assigns, PROVIDED THAT this SECTION 7 shall not be construed to permit any
     future assignments of the Contract of Sale.

8.   COUNTERPARTS. This Assignment may be signed in counterparts, each of which
     shall be deemed an original and all of which, when taken together, shall
     constitute one and the same instrument.

9.   GOVERNING LAW. This Assignment shall be governed by and construed in
     accordance with the Laws of the State of New York.


           [The remainder of this page is intentionally left blank.]

                                       3


     IN WITNESS WHEREOF, the parties hereto have executed this Assignment by
their respective duly authorized representatives as of the date first above
written.

                                       ASSIGNOR:

                                       DAI-ICHI LIFE INVESTMENT PROPERTIES,
                                       INC.


                                       By: /S/ HITOSHI YAMAUCHI
                                          --------------------------------------
                                          Name:  Hitoshi Yamauchi
                                          Title: Senior Vice President



                                       ASSIGNEE:

                                       BP/CGCENTER II LLC,
                                       a Delaware limited liability company


                                       By: /s/ ROBERT E. SELSAM
                                          --------------------------------------
                                          Name:  Robert E. Selsam
                                          Title: Vice President



AGREED TO AND ACCEPTED BY:


CITIBANK, N.A.

By: /s/ MICHAEL W. BROIDO
   ------------------------------------
   Name:  Michael W. Broido
   Title: Vice President

                                      S-1