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                        ASSIGNMENT OF PURCHASE AGREEMENT


     This Assignment of Purchase Agreement  ("Assignment") is made as of January
15,  1998,  by and between  TRINET  CORPORATE  REALTY  TRUST,  INC.,  a Maryland
corporation  ("Assignor"),  and TRINET ESSENTIAL  FACILITIES X, INC., a Maryland
corporation ("Assignee"), with reference to the following facts:

     A. ICG HOLDINGS,  INC., a Colorado corporation  ("Seller"),  as seller, and
Assignor,  as buyer,  entered into that certain Purchase Agreement,  dated as of
December 9, 1997 (the "Purchase  Agreement"),  covering the Property (as defined
in the Purchase Agreement).

     B. Assignee is a wholly-owned subsidiary of Assignor.

     C. The parties  desire to enter into this  Assignment to assign  Assignor's
rights under the Purchase Agreement to Assignee.

     THEREFORE, the parties agree as follows:

     1. Assignment and Assumption.

          (a) Assignor hereby assigns and transfers to Assignee all right, title
     and interest of Assignor in, to and under the Purchase Agreement.

          (b) Assignee hereby accepts the foregoing assignment,  and assumes and
     agrees to perform  all of the  covenants  and  agreements  in the  Purchase
     Agreement to be performed by the Buyer thereunder.

     2. Further  Assurances.  Assignor and Assignee  agree to execute such other
documents and perform such other acts as may be  reasonably  necessary or proper
and usual to effect this Assignment.

     3.  Governing  Law. This  Assignment  shall be governed by and construed in
accordance with the laws of the State of Colorado.

     4. Successors and Assigns.  This Assignment shall be binding upon and shall
inure to the benefit of Assignor  and  Assignee  and their  respective  personal
representatives, heirs, successors and assigns.


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     5.  Counterparts.  This  Assignment may be signed in multiple  counterparts
which, when signed by all parties, shall constitute a binding agreement.

     IN WITNESS WHEREOF,  Assignor and Assignee have executed this Assignment as
of the date first hereinabove written.


ASSIGNOR:                     TRINET CORPORATE REALTY TRUST, INC., 
                              a Maryland corporation


                              By  /s/ Gary P. Lyon
                                 ---------------------------------
                                   Gary P. Lyon  

                                 Its  Executive Vice President


ASSIGNEE:                     TRINET ESSENTIAL FACILITIES X, INC., 
                              a Maryland corporation


                              By  /s/ Gary P. Lyon
                                 ---------------------------------
                                   Gary P. Lyon  

                                 Its  Executive Vice President