<PAGE>

                                                                    EXHIBIT 10.2

                             AMENDMENT NO. FIVE TO
                           PLATINUM TECHNOLOGY, INC.
                                 OFFICE LEASE

     THIS AMENDMENT NO. FIVE ("Amendment No. Five"), to that certain Oakbrook
Terrace Corporate Center, Phase III ("Building") Office Lease dated May 6, 1992
("Base Lease"), as amended by Amendment No. One to Office Lease dated May 3,
1993, ("Amendment No. One"), Amendment No. Two to Office Lease dated October 26,
1993, Amendment No. Three to Office Lease dated December 22, 1994, ("Amendment
No. Three"), and Amendment No. Four to Platinum Technology, Inc. Office Lease
dated March 9, 1995 by and between LaSalle National Trust, N.A., not personally,
but as Trustee under Trust Agreement dated May 28, 1986, and known as Trust No.
111156 ("Landlord") and Platinum Technology, Inc., a Delaware corporation
("Tenant"), (the "Lease") is made as of this 1st day of December, 1996.


                                   RECITALS

     WHEREAS, in Amendment No. Three, the 7,541 rentable square feet referred to
therein as the "First Option Space" was erroneously described and was meant to
relate to 7,541 rentable square feet of the Second Expansion Space (being that
portion of the Second Expansion Space net of the Initial Second Expansion
Space), which for purposes of this Lease, will hereafter be referred to as the
"Balance of Second Expansion Space"; and

     WHEREAS, under the Base Lease, the Second Expansion Space was to be
incorporated into the Premises on the first day of the forty-fifth month of the
Lease Term (August 15, 1996), at which time the Base Rent, Tenant's
Proportionate Share of the Premises and the Premises occupied by Tenant under
the Lease was to increase ("Adjusted Items");

     WHEREAS, the Initial Second Expansion Space and the Balance of Second
Expansion Space (collectively comprising the Second Expansion Space in its
entirety) was incorporated into the Premises by virtue of Amendment No. One and
Amendment No. Three, respectively;

     WHEREAS, while the Adjusted Items had been incorporated into the Lease to
reflect Tenant's early occupancy of the two components of the Second Expansion
Space, corresponding changes effective August 15, 1996 were inadvertently
omitted; and

     WHEREAS, Landlord and Tenant are entering into this Amendment No. Five to
correct the inadvertent reference to the "First Option Space" in Amendment No.
Three and the failure to adjust the August 15, 1996 Adjusted Items associated
with the early incorporation of the Second Expansion Space.


<PAGE>
 
     NOW THEREFORE, Landlord and Tenant mutually agree as follows:

     1. The above Recitals are incorporated into the text of this Amendment No. 
Five as though fully set forth herein.

     2. Section 1.H. of the Lease shall be deleted in its entirety and a Revised
Schedule of Base Rental attached to this Amendment No. Five as Exhibit A-1 shall
be inserted in lieu thereof.

     3. Section 1.I. of the Lease shall be adjusted as follows:

<TABLE>
<CAPTION>
For the Period of                     Square Feet
-----------------                     -----------
<S>                                   <C>
December 15, 1992 to                       
March 31, 1993                             86,119

April 1, 1993 to 
December 14, 1993                         104,757

December 15, 1993 to
November 30, 1994                         115,409

December 1, 1994 to
May 31, 1995                              122,950

June 1, 1995 to
December 14, 1995                         156,946

December 15, 1995 to
December 14, 2002                         169,319
</TABLE>

4. Section 1.K. of the Lease shall be adjusted as follows:

<TABLE>
<CAPTION>
For the Period of             Percentage Interest
-----------------             -------------------
<S>                           <C>
December 15, 1992 to                     
March 31, 1993:                          .3483285

April 1, 1993 to
December 14, 1993                        .4237143
</TABLE>

                                       2
<PAGE>
 
December 15, 1993 to
November 30, 1994                                                 .4667988

December 1, 1994 to
May 31, 1995                                                      .4973001

June 1, 1995 to
December 14, 1995                                                 .6348049

December 15, 1995 to
December 14, 2002                                                 .6848504

     5.  Section 1.M. of the Lease shall be amended as follows:

     1.M. Floor of Premises
          -----------------
     December 15, 1992 to March 31, 1993: Tenth Floor (24,500 r.s.f.), Ninth
     Floor (24,582 r.s.f.), Eighth Floor (24,664 r.s.f.) and the southern half
     of the Seventh Floor (12,373 r.s.f.)

     April 1, 1993 to December 14, 1993: Tenth Floor (24,500 r.s.f.), Ninth
     Floor (24,582 r.s.f.), Eighth Floor (24,664 r.s.f.), Seventh Floor (12,373
     r.s.f.), Sixth Floor (17,283 r.s.f.), Fifth Floor (1,355 r.s.f.)

     December 15, 1993 to November 30, 1994: Tenth Floor (24,500 r.s.f.), Ninth
     Floor (24,582 r.s.f.), Eighth Floor (24,664 r.s.f.), Seventh Floor (12,373
     r.s.f.), Sixth Floor (17,283 r.s.f.), Fifth Floor (1,355 r.s.f.), and
     Second Floor (10,652 r.s.f.)

     December 1, 1994 to May 31, 1995: Tenth Floor (24,500 r.s.f.), Ninth Floor
     (24,582 r.s.f.), Eighth Floor (24,664 r.s.f.), Seventh Floor (12,373
     r.s.f.), Sixth Floor (24,824 r.s.f.), Fifth Floor (1,355 r.s.f.), and
     Second Floor (10,652 r.s.f.)

     June 1, 1995 to December 14, 1995: Tenth Floor (24,500 r.s.f.), Ninth Floor
     (24,582 r.s.f.), Eighth Floor (24,664 r.s.f.), Seventh Floor (12,373
     r.s.f.), Sixth Floor (24,824 r.s.f.), Fifth Floor (1,355 r.s.f.), Third
     Floor (25,027 r.s.f.), and Second Floor (19,621 r.s.f.)

     December 15, 1995 to December 14, 2002: Tenth Floor (24,500 r.s.f.), Ninth
     Floor (24,582 r.s.f.), Eighth Floor (24,664 r.s.f.), Seventh Floor (24,746
     square feet), Sixth Floor (24,824 square feet), Fifth Floor (1,355 r.s.f.),
     Third Floor (25,027 r.s.f.), and Second Floor (19,621 r.s.f.)

                                      3 

<PAGE>

     6.  The following shall be inserted as subparagraph (19) in Section 7A(1) 
of the Lease as an additional exclusion from the definition of Expenses:

      "Costs for any After-Hours HVAC provided by Landlord and paid for by
      Tenant per Section 3A(1) of the Lease. Costs shall be defined as $10 per
      hour for each Building Zone requiring After-Hours HVAC."

     7.  Except as provided in this Amendment No. Five, the Lease shall remain
in full force and effect and is hereby ratified and confirmed. To the extent
that any of the covenants, terms and conditions of the Lease conflict with the
covenants, terms and conditions of this Amendment No. Five, the covenants, terms
and conditions of this Amendment No. Five shall govern and control.

     8.  This Amendment No. Five to Office Lease is executed by LaSalle National
Trust, N.A., as successor trustee to LaSalle National Bank, not personally but
as Trustee, as aforesaid, in the exercise of the power and authority conferred
upon and vested in it as such Trustee and under the express direction of the
beneficiaries of a certain Trust Agreement dated May 28, 1986, and known as
Trust No. 111156, to all provisions of which Trust Agreement the Lease, as
amended, is expressly made subject. It is expressly understood and agreed that
nothing herein or in said Lease contained shall be construed as creating any
liability whatsoever against said Trustee personally, and in particular, without
limiting the generality of the foregoing, there shall be no personal liability
to pay any indebtedness accruing hereunder or to perform any covenant, either
express or implied, herein contained, or to keep, preserve or sequester any
property of said Trust; that all personal liability of said Trustee of every
sort, if any, is hereby expressly waived by said Lessee and by every person now
or hereafter claiming any right or security hereunder; and that, so far as said
Trustee is concerned, the owner of any indebtedness or liability accruing
hereunder shall look solely to the premises hereby leased for the payment
thereof. It is further understood and agreed that said Trustee has no agents or
employees and merely holds naked legal title to the property herein described;
that said Trustee has no control over and under the Lease, as amended, and
assumes no responsibility for (a) the management or control of such property;
(b) the upkeep, inspection, maintenance or repair of such property; (c) the
collection of rents or rental of such property; or (d) the conduct of any
business which is carried on upon such premises.

                                      4 
<PAGE>
 
     IN WITNESS WHEREOF, Landlord and Tenant have executed this Amendment No. 
Five to Office Lease on the day and in the year first above written.

LANDLORD:                           TENANT:
---------                           -------

LaSalle National Trust, N.A.,       Platinum Technology, Inc.,
not personally, but solely          a Delaware corporation
as Trustee under Trust 
Agreement dated May 28, 1986
and known as Trust No. 111156

By:                                 By:  /s/ Michael Cullinane
   -----------------------              -----------------------------
   VICE PRESIDENT                        Michael Cullinane
                                         
                                    Its: Executive Vice President and
                                         Chief Financial Officer      
                                         ----------------------------  

                                    ATTEST:

                                    By:  /s/ Arthur Anton
                                        -----------------------------  
                                         Arthur Anton
                                                                 

                                    Its: Director of Real Estate 
                                         ----------------------------  


                                       5
<PAGE>

                                  EXHIBIT A-1

PLATINUM technology, inc.
Monthly Base Rent Summary
Oakbrook Terrace Corporate Center III

<TABLE>
<CAPTION>
--------------------------------------------------------------------------------------------------------------------------------
Space Name:    Original Premises                 First Expansion Space First Option Space          Initial 2nd Expansion Space
Amendment #:   Original Lease                    Original Lease        1                           1
Square Feet:   86,119                            12,373                11,171                      6,112
Description:      24,500    10th Floor           7th Floor             6th Floor                   6th Floor
                  24,582     9th Floor
                  24,664     8th Floor
                  12,373     7th Floor
--------------------------------------------------------------------------------------------------------------------------------

                              Rent      Monthly           Monthly                 Rent    Monthly              Rent    Monthly
               Rent/SF     Abatement     Rent    Rent/SF    Rent       Rent/SF  Abatement   Rent   Rent/SF  Abatement    Rent
--------------------------------------------------------------------------------------------------------------------------------
<S>            <C>         <C>      <C>         <C>     <C>            <C>      <C>      <C>       <C>      <C>         <C>
12/15/92        $16.00      $16.00        0.00
1/1/93          $16.00      $16.00        0.00
2/1/93          $16.00      $16.00        0.00
3/1/93          $16.00      $16.00        0.00
4/1/93          $16.00      $16.00        0.00                         $11.50   $11.50        0.00 $11.50   $11.50          0.00
5/1/93          $16.00      $16.00        0.00                         $11.50   $11.50        0.00 $11.50   $11.50          0.00
6/1/93          $16.00      $16.00        0.00                         $11.50   $11.50        0.00 $11.50   $11.50          0.00
7/1/93          $16.00      $16.00        0.00                         $11.50   $11.50        0.00 $11.50   $11.50          0.00
8/1/93          $16.00      $16.00        0.00                         $11.50   $11.50        0.00 $11.50   $11.50          0.00
9/1/93          $16.00      $16.00        0.00                         $11.50   $11.50        0.00 $11.50   $11.50          0.00
10/1/93         $16.00      $16.00        0.00                         $11.50   $11.50        0.00 $11.50   $11.50          0.00
11/1/93         $16.00      $16.00        0.00                         $11.50   $11.50        0.00 $11.50   $11.50          0.00
12/1/93         $16.00      $16.00        0.00                         $11.50   $11.50        0.00 $11.50   $11.50          0.00
12/15/93        $16.00      $16.40        0.00                         $11.50   $11.50        0.00 $11.50   $11.50          0.00
--------------------------------------------------------------------------------------------------------------------------------
1/1/94          $16.40      $16.40        0.00                         $11.50   $ 4.91    6,137.68 $11.50   $11.50          0.00
2/1/94          $16.40      $16.40        0.00                         $11.50   $ 4.91    6,137.68 $11.50   $11.50          0.00
3/1/94          $16.40      $16.40        0.00                         $11.50   $ 4.91    6,137.68 $11.50   $11.50          0.00
4/1/94          $16.40      $16.40        0.00                         $11.85   $ 4.91    6,458.85 $11.85   $11.85          0.00
5/1/94          $16.40      $16.40        0.00                         $11.85   $ 4.91    6,458.85 $11.85   $11.85          0.00
6/1/94          $16.40      $16.40        0.00                         $11.85   $ 4.91    6,458.85 $11.85   $11.85          0.00
7/1/94          $16.40      $16.40        0.00                         $11.85   $ 4.91    6,458.85 $11.85   $11.85          0.00
8/1/94          $16.40      $16.40        0.00                         $11.85   $ 4.91    6,458.85 $11.85   $11.85          0.00
9/1/94          $16.40      $16.40        0.00                         $11.85   $ 4.91    6,458.85 $11.85   $11.85          0.00
10/1/94         $16.40      $16.40        0.00                         $11.85   $ 4.91    6,458.85 $11.85   $11.85          0.00
11/1/94         $16.40      $16.40        0.00                         $11.85   $ 4.91    6,458.85 $11.85   $11.85          0.00
12/1/94         $16.40      $16.40        0.00                         $11.85   $ 4.91    2,916.90 $11.85   $11.85          0.00
12/15/94        $16.81      $16.81        0.00                         $11.85   $ 4.91    3,541.95 $11.85   $11.85          0.00
--------------------------------------------------------------------------------------------------------------------------------
1/1/95          $16.81      $16.81        0.00                         $11.85   $ 4.91    6,458.85 $11.85   $11.85          0.00
2/1/95          $16.81      $16.81        0.00                         $11.85   $ 4.91    6,458.85 $11.85   $11.85          0.00
3/1/95          $16.81      $16.81        0.00                         $11.85   $ 4.91    6,458.85 $11.85   $11.85          0.00
4/1/95          $16.81      $16.81        0.00                         $12.21   $ 4.91    6,789.65 $12.21               6,218.96
5/1/95          $16.81      $16.81        0.00                         $12.21   $ 4.91    6,789.65 $12.21               6,218.96
6/1/95          $16.81      $16.81        0.00                         $12.21   $ 4.91    6,789.65 $12.21               6,218.96
7/1/95          $16.81      $16.81        0.00                         $12.21   $ 4.91    6,789.65 $12.21               6,218.96
8/1/95          $16.81      $16.81        0.00                         $12.21   $ 4.91    6,789.65 $12.21               6,218.96
9/1/95          $16.81      $16.81        0.00                         $12.21   $ 4.91    6,789.65 $12.21               6,218.96
10/1/95         $16.81      $16.81        0.00                         $12.21   $ 4.91    6,789.65 $12.21               6,218.96
11/1/95         $16.81      $ 7.84   64,340.46                         $12.21   $ 4.91    6,789.65 $12.21               6,218.96
12/1/95         $16.81               54,481.84                         $12.21   $ 4.91    3,066.29 $12.21               2,808.56
12/15/95        $17.23               67,809.45   $17.23  9,742.41      $12.21   $ 4.91    3,723.36 $12.21               3,410.40
--------------------------------------------------------------------------------------------------------------------------------
1/1/96          $17.23              123,652.53   $17.23 17,765.57      $12.21   $ 4.91    6,789.65 $12.21               6,218.96
2/1/96          $17.23              123,652.53   $17.23 17,765.57      $12.21   $ 4.91    6,789.65 $12.21               6,218.96
3/1/96          $17.23              123,652.53   $17.23 17,765.57      $12.21   $ 4.91    6,789.65 $12.21               6,218.96
4/1/96          $17.23              123,652.53   $17.23 17,765.57      $12.58   $ 4.91    7,130.37 $12.58               6,407.41
5/1/96          $17.23              123,652.53   $17.23 17,765.57      $12.58   $ 4.91    7,130.37 $12.58               6,407.41
6/1/96          $17.23              123,652.53   $17.23 17,765.57      $12.58   $ 4.91    7,130.37 $12.58               6,407.41
7/1/96          $17.23              123,652.53   $17.23 17,765.57      $12.58   $ 4.91    7,130.37 $12.58               6,407.41
8/1/96          $17.23              123,652.53   $17.23 17,765.57      $12.58   $ 4.91    7,130.37 $15.13               7,706.21
9/1/96          $17.23              123,652.53   $17.23 17,765.57      $12.58   $ 4.91    7,130.37 $17.23               8,775.81
10/1/96         $17.23              123,652.53   $17.23 17,765.57      $12.58   $ 4.91    7,130.37 $17.23               8,775.81
11/1/96         $17.23              123,652.53   $17.23 17,765.57      $12.58   $ 4.91    7,130.37 $17.23               8,775.81
12/1/96         $17.23               55,843.08   $17.23  8,023.16      $12.58   $ 4.91    3,220.17 $17.23               3,963.27
12/15/96        $17.66               69,501.74   $17.66  9,985.54      $12.58   $ 4.91    3,910.20 $17.66               4,932.65
--------------------------------------------------------------------------------------------------------------------------------
1/1/97          $17.66              126,738.46   $17.66 18,208.93      $12.58   $ 4.91    7,130.37 $17.66               8,994.83
2/1/97          $17.66              126,738.46   $17.66 18,208.93      $12.58   $ 4.91    7,130.37 $17.66               8,994.83
3/1/97          $17.66              126,738.46   $17.66 18,208.93      $12.58   $ 4.91    7,130.37 $17.66               8,994.83
4/1/97          $17.66              126,738.46   $17.66 18,208.93      $12.94   $ 4.91    7,481.32 $17.66               8,994.83
5/1/97          $17.66              126,738.46   $17.66 18,208.93      $12.94   $ 4.91    7,481.32 $17.66               8,994.83
6/1/97          $17.66              126,738.46   $17.66 18,208.93      $12.94   $ 4.91    7,481.32 $17.66               8,994.83
7/1/97          $17.66              126,738.46   $17.66 18,208.93      $12.94   $ 4.91    7,481.32 $17.66               8,994.83
8/1/97          $17.66              126,738.46   $17.66 18,208.93      $12.94   $ 4.91    7,481.32 $17.66               8,994.83
9/1/97          $17.66              126,738.46   $17.66 18,208.93      $12.94   $ 4.91    7,481.32 $17.66               8,994.83
10/1/97         $17.66              126,738.46   $17.66 18,208.93      $12.94   $ 4.91    7,481.32 $17.66               8,994.83
11/1/97         $17.66              126,738.46   $17.66 18,208.93      $12.94   $ 4.91    7,481.32 $17.66               8,994,83
12/1/97         $17.66               57,236.72   $17.66  8,223.39      $12.94   $ 2.45    3,157.64 $17.66               8,994.83
12/15/97        $18.10               71,233.38   $18.10 10,234.33      $18.10             9,240.10 $18.10               5,055.54
--------------------------------------------------------------------------------------------------------------------------------
1/1/98          $18.10              129,896.16   $18.10 18,662.61      $18.10            16,849.59 $18.10               9,218.93
2/1/98          $18.10              129,896.16   $18.10 18,662.61      $18.10            16,849.59 $18.10               9,218.93
3/1/98          $18.10              129,896.16   $18.10 18,662.61      $18.10            16,849.59 $18.10               9,218.93
4/1/98          $18.10              129,896.16   $18.10 18,662.61      $18.10            16,849.59 $18.10               9,218.93
5/1/98          $18.10              129,896.16   $18.10 18,662.61      $18.10            16,849.59 $18.10               9,218.93
</TABLE>
<TABLE>
<CAPTION>
-------------------------------------------------------------------------------------------------------------------------
Space Name:    3rd Expansion Space                    4th Expansion Space                Balance 2nd Expansion Space
Amendment #:   1                                      2                                  3(5)
Square Feet:   1,355                                  10,652                             7,541
Description:   5th Floor                              2nd Floor                          6th Floor

-------------------------------------------------------------------------------------------------------------------------

                             Rent      Monthly                  Rent     Monthly                          Rent    Monthly
                Rent/SF    Abatement     Rent         Rent/SF Abatement    Rent          Rent/SF       Abatement    Rent
-------------------------------------------------------------------------------------------------------------------------
<S>            <C>         <C>        <C>             <C>     <C>       <C>              <C>           <C>       <C>
12/15/92
1/1/93
2/1/93
3/1/93
4/1/93          $16.00      $16.00        0.00
5/1/93          $16.00      $16.00        0.00
6/1/93          $16.00      $16.00        0.00
7/1/93          $16.00      $16.00        0.00
8/1/93          $16.00      $16.00        0.00
9/1/93          $16.00      $16.00        0.00
10/1/93         $16.00      $16.00        0.00
11/1/93         $16.00      $16.00        0.00
12/1/93         $16.00      $16.00        0.00
12/15/93        $16.40      $16.40        0.00        $16.40  $16.40        00.00
-------------------------------------------------------------------------------------------------------------------------
1/1/94          $16.40      $16.40        0.00        $16.40  $16.40        00.00
2/1/94          $16.40      $16.40        0.00        $16.40  $16.40        00.00
3/1/94          $16.40      $16.40        0.00        $16.40  $16.40        00.00
4/1/94          $16.40      $16.40        0.00        $16.40  $16.40        00.00
5/1/94          $16.40      $16.40        0.00        $16.40  $16.40        00.00
6/1/94          $16.40      $16.40        0.00        $16.40  $16.40        00.00
7/1/94          $16.40      $16.40        0.00        $16.40  $16.40        00.00
8/1/94          $16.40      $16.40        0.00        $16.40  $16.40        00.00
9/1/94          $16.40      $16.40        0.00        $16.40  $16.40        00.00
10/1/94         $16.40      $16.40        0.00        $16.40  $16.40        00.00
11/1/94         $16.40      $16.40        0.00        $16.40  $16.40        00.00
12/1/94         $16.40      $16.40        0.00        $16.40  $16.40        00.00        $16.40        $16.40        0.00
12/15/94        $16.81      $16.81        0.00        $16.81  $16.81        00.00        $16.81        $16.81        0.00
-------------------------------------------------------------------------------------------------------------------------
1/1/95          $16.81      $16.81        0.00        $16.81  $16.81        00.00        $16.81        $16.81        0.00
2/1/95          $16.81      $16.81        0.00        $16.81  $16.81        00.00        $16.81        $16.81        0.00
3/1/95          $16.81      $16.81        0.00        $16.81  $16.81        00.00        $14.04                  8,822.97
4/1/95          $16.81      $16.81        0.00        $16.81  $16.81        00.00        $14.04                  8,822.97
5/1/95          $16.81      $16.81        0.00        $16.81  $16.81        00.00        $14.04                  8,822.97
6/1/95          $16.81      $16.81        0.00        $16.81  $16.81        00.00        $14.04                  8,822.97
7/1/95          $16.81      $16.81        0.00        $16.81  $16.81        00.00        $14.04                  8,822.97
8/1/95          $16.81      $16.81        0.00        $16.81            14,921.68        $14.04                  8,822.97
9/1/95          $16.81      $16.81        0.00        $16.81            14,921.68        $14.04                  8,822.97
10/1/95         $16.81      $16.81        0.00        $16.81            14,921.68        $14.04                  8,822.97
11/1/95         $16.81      $16.81        0.00        $16.81            14,921.68        $14.04                  8,822.97
12/1/95         $16.81      $16.81        0.00        $16.81             6,738.82        $14.04                  3,984.57
12/15/95        $17.23      $17.23        0.00        $17.23             8,387.30        $14.46                  4,983.14
-------------------------------------------------------------------------------------------------------------------------
1/1/96          $17.23      $17.23        0.00        $17.23            15,294.50        $14.46                  9,086.91
2/1/96          $17.23      $17.23        0.00        $17.23            15,294.50        $14.46                  9,086.91
3/1/96          $17.23      $17.23        0.00        $17.23            15,294.50        $14.46                  9,086.91
4/1/96          $17.23                1,945.55        $17.23            15,294.50        $14.46                  9,086.91
5/1/96          $17.23                1,945.55        $17.23            15,294.50        $14.46                  9,086.91
6/1/96          $17.23                1,945.55        $17.23            15,294.50        $14.46                  9,086.91
7/1/96          $17.23                1,945.55        $17.23            15,294.50        $14.46                  9,086.91
8/1/96          $17.23                1,945.55        $17.23            15,294.50        $14.46                  9,086.91
9/1/96          $17.23                1,945.55        $17.23            15,294.50        $14.46                  9,086.91
10/1/96         $17.23                1,945.55        $17.23            15,294.50        $14.46                  9,086.91
11/1/96         $17.23                1,945.55        $17.23            15,294.50        $14.46                  9,086.91
12/1/96         $17.23                  878.64        $17.23             6,907.19        $14.46                  4,103.76
12/15/96        $17.66                1,093,54        $17.66             8,596.62        $14.89                  5,131.33
-------------------------------------------------------------------------------------------------------------------------
1/1/97          $17.66                1,994.11        $17.66            15,676.19        $14.89                  9,357.12
2/1/97          $17.66                1,994.11        $17.66            15,676.19        $14.89                  9,357.12
3/1/97          $17.66                1,994.11        $17.66            15,676.19        $14.89                  9,357.12
4/1/97          $17.66                1,994.11        $17.66            15,676.19        $14.89                  9,357.12
5/1/97          $17.66                1,994.11        $17.66            15,676.19        $14.89                  9,357.12
6/1/97          $17.66                1,994.11        $17.66            15,676.19        $14.89                  9,357.12
7/1/97          $17.66                1,994.11        $17.66            15,676.19        $14.89                  9,357.12
8/1/97          $17.66                1,994.11        $17.66            15,676.19        $14.89                  9,357.12
9/1/97          $17.66                1,994.11        $17.66            15,676.19        $14.89                  9,357.12
10/1/97         $17.66                1,994.11        $17.66            15,676.19        $14.89                  9,357.12
11/1/97         $17.66                1,994.11        $17.66            15,676.19        $14.89                  9,357.12
12/1/97         $17.66                  900.57        $17.66             7,079.57        $14.89                  4,225.80
12/15/97        $18.10                1,120.79        $18.10             8,810.81        $15.33                  5,282.96
-------------------------------------------------------------------------------------------------------------------------
1/1/98          $18.10                2,043.79        $18.10            16,066.77        $15.33                  9,633.63
2/1/98          $18.10                2,043.79        $18.10            16,066.77        $15.33                  9,633.63
3/1/98          $18.10                2,043.79        $18.10            16,066.77        $15.33                  9,633.63
4/1/98          $18.10                2,043.79        $18.10            16,066.77        $15.33                  9,633.63
5/1/98          $18.10                2,043.79        $18.10            16,066.77        $15.33                  9,633.63
</TABLE>
<TABLE>
<CAPTION>
-------------------------------------------------------------------------------------------------
Space Name:    5th Expansion Space                    6th Expansion Space                Totals
Amendment #:   3                                      4
Square Feet:   6,919                                  27,077                             169,319
Description:   2nd Floor                                25,027 3rd Floor
                                                         2,050 2nd Floor
-------------------------------------------------------------------------------------------------
                                                                                         Total
                              Rent      Monthly                  Rent      Monthly       From
               Rent/SF     Abatement     Rent         Rent/SF  Abatement     Rent        Detail
-------------------------------------------------------------------------------------------------
<S>            <C>         <C>        <C>            <C>      <C>       <C>            <C>
12/15/92                                                                                     0.00
1/1/93                                                                                       0.00
2/1/93                                                                                       0.00
3/1/93                                                                                       0.00
4/1/93                                                                                       0.00
5/1/93                                                                                       0.00
6/1/93                                                                                       0.00
7/1/93                                                                                       0.00
8/1/93                                                                                       0.00
9/1/93                                                                                       0.00
10/1/93                                                                                      0.00
11/1/93                                                                                      0.00
12/1/93
12/15/93                                                                                     0.00
-------------------------------------------------------------------------------------------------
1/1/94                                                                                   6,137.68
2/1/94                                                                                   6,137.68
3/1/94                                                                                   6,137.68
4/1/94                                                                                   6,458.85
5/1/94                                                                                   6,458.85
6/1/94                                                                                   6,458.85
7/1/94                                                                                   6,458.85
8/1/94                                                                                   6,458.85
9/1/94                                                                                   6,458.85
10/1/94                                                                                  6,458.85
11/1/94                                                                                  6,458.85
12/1/94
12/15/94                                                                                 6,458.85
-------------------------------------------------------------------------------------------------
1/1/95                                                                                   6,458.85
2/1/95                                                                                   6,458.85
3/1/95                                                                                  15,281.82
4/1/95                                                                                  21,831.58
5/1/95                                                                                  21,831.58
6/1/95          $16.81      $16.81        0.00        $16.81  $16.81        00.00       21,831.58
7/1/95          $16.81      $16.81        0.00        $16.81  $16.81        00.00       21,831.58
8/1/95          $16.81      $16.81        0.00        $16.81  $16.81        00.00       36,753.26
9/1/95          $13.39                7,720.45        $16.81            37,930.36       82,404.07
10/1/95         $13.39                7,720.45        $16.81            37,930.36       82,404.07
11/1/95         $13.39                7,720.45        $16.81            37,930.36      146,744.53
12/1/95         $13.39                3,486.66        $16.81            17,129.84
12/15/95        $13.81                4,366.60        $17.23            21,320.23      215,439.47
-------------------------------------------------------------------------------------------------
1/1/96          $13.81                7,962.62        $17.23            38,878.06      225,648.78
2/1/96          $13.81                7,962.62        $17.23            38,878.06      225,648.78
3/1/96          $13.81                7,962.62        $17.23            38,878.06      225,648.78
4/1/96          $13.81                7,962.62        $17.23            38,878.06      228,123.51
5/1/96          $13.81                7,962.62        $17.23            38,878.06      228,123.51
6/1/96          $13.81                7,962.62        $17.23            38,878.06      228,123.51
7/1/96          $13.81                7,962.62        $17.23            38,878.06      228,123.51
8/1/96          $13.81                7,962.62        $17.23            38,878.06      229,422.31
9/1/96          $13.81                7,962.62        $17.23            38,878.06      230,491.91
10/1/96         $13.81                7,962.62        $17.23            38,878.06      230,491.91
11/1/96         $13.81                7,962.62        $17.23            38,878.06      230,491.91
12/1/96         $13.81                3,596.02        $17.23            17,557.83
12/15/96        $14.24                4,502.56        $17.66            21,852.30      233,599.60
-------------------------------------------------------------------------------------------------
1/1/97          $14.24                8,210.55        $17.66            39,848.32      236,158.88
2/1/97          $14.24                8,210.55        $17.66            39,848.32      236,158.88
3/1/97          $14.24                8,210.55        $17.66            39,848.32      236,158.88
4/1/97          $14.24                8,210.55        $17.66            39,848.32      236,509.83
5/1/97          $14.24                8,210.55        $17.66            39,848.32      236,509.83
6/1/97          $14.24                8,210.55        $17.66            39,848.32      236,509.83
7/1/97          $14.24                8,210.55        $17.66            39,848.32      236,509.83
8/1/97          $14.24                8,210.55        $17.66            39,848.32      236,509.83
9/1/97          $14.24                8,210.55        $17.66            39,848.32      236,509.83
10/1/97         $14.24                8,210.55        $17.66            39,848.32      236,509.83
11/1/97         $14.24                8,210.55        $17.66            39,848.32      236,509.83
12/1/97         $14.24                3,707.99        $17.66            17,996.01
12/15/97        $14.68                4,641.68        $18.10            22,396.76      244,606.21
-------------------------------------------------------------------------------------------------
1/1/98          $14.68                8,464.24        $18.10            40,841.14      251,676.86
2/1/98          $14.68                8,464.24        $18.10            40,841.14      251,676.86
3/1/98          $14.68                8,464.24        $18.10            40,841.14      251,676.86
4/1/98          $14.68                8,464.24        $18.10            40,841.14      251,676.86
5/1/98          $14.68                8,464.24        $18.10            40,841.14      251,676.86
</TABLE>
<PAGE>

                                  EXHIBIT A-1

PLATINUM technology, inc.
Monthly Base Rent Summary
Oakbrook Terrace Corporate Center III

<TABLE>
<CAPTION>
-----------------------------------------------------------------------------------------------------
Space Name:  Original Premises              First Expansion Space      First Option Space
Amendment #  Original Lease                 Original Lease             1
Square Feet: 86,119                         12,373                     11,171
Description:      24,500  10th Floor        7th Floor                  6th Floor
                  24,582   9th Floor
                  24,664   8th Floor
                  12,373   7th Floor
-----------------------------------------------------------------------------------------------------
                        Rent       Monthly                 Monthly                Rent      Monthly
             Rent/SF  Abatement     Rent       Rent/SF      Rent       Rent/SF   Abatement     Rent
-----------------------------------------------------------------------------------------------------
<S>          <C>      <C>       <C>           <C>        <C>           <C>       <C>         <C>
6/1/98       $18.10             129,896.16    $18.10     18,662.61     $18.10               16,849.59
7/1/98       $18.10             129,896.16    $18.10     18,662.61     $18.10               16,849.59
8/1/98       $18.10             129,896.16    $18.10     18,662.61     $18.10               16.849.59
9/1/98       $18.10             129,896.16    $18.10     18,662.61     $18.10               16.849.59
10/1/98      $18.10             129,896.16    $18.10     18,662.61     $18.10               16.849.59
11/1/98      $18.10             129,896.16    $18.10     18,662.61     $18.10               16.849.59
12/1/98      $18.10              58,662.78    $18.10      8,428.27     $18.10                7,609.49
12/15/98     $18.56              73,043.73    $18.56     10,494.43     $18.56                9,474.93
-----------------------------------------------------------------------------------------------------
1/1/99       $18.56             133,197.39    $18.56     19,136.91     $18.56               17,277.81
2/1/99       $18.56             133,197.39    $18.56     19,136.91     $18.56               17,277.81
3/1/99       $18.56             133,197.39    $18.56     19,136.91     $18.56               17,277.81
4/1/99       $18.56             133,197.39    $18.56     19,136.91     $18.56               17,277.81
5/1/99       $18.56             133,197.39    $18.56     19,136.91     $18.56               17,277.81
6/1/99       $18.56             133,197.39    $18.56     19,136.91     $18.56               17,277.81
7/1/99       $18.56             133,197.39    $18.56     19,136.91     $18.56               17,277.81
8/1/99       $18.56             133,197.39    $18.56     19,136.91     $18.56               17,277.81
9/1/99       $18.56             133,197.39    $18.56     19,136.91     $18.56               17,277.81
10/1/99      $18.56             133,197.39    $18.56     19,136.91     $18.56               17,277.81
11/1/99      $18.56             133,197.39    $18.56     19,136.91     $18.56               17,277.81
12/1/99      $18.56              60,153.66    $18.56      8,642.47     $18.56                7,802.88
12/15/99     $19.02              74,854.08    $19.02     10,754.53     $19.02                9,709.76
-----------------------------------------------------------------------------------------------------
1/1/00       $19.02             136,498.62    $19.02     19,611.21     $19.02               17,706.04
2/1/00       $19.02             136,498.62    $19.02     19,611.21     $19.02               17,706.04
3/1/00       $19.02             136,498.62    $19.02     19,611.21     $19.02               17,706.04
4/1/00       $19.02             136,498.62    $19.02     19,611.21     $19.02               17,706.04
5/1/00       $19.02             136,498.62    $19.02     19,611.21     $19.02               17,706.04
6/1/00       $19.02             136,498.62    $19.02     19,611.21     $19.02               17,706.04
7/1/00       $19.02             136,498.62    $19.02     19,611.21     $19.02               17,706.04
8/1/00       $19.02             136,498.62    $19.02     19,611.21     $19.02               17,706.04
9/1/00       $19.02             136,498.62    $19.02     19,611.21     $19.02               17,706.04
10/1/00      $19.02             136,498.62    $19.02     19,611.21     $19.02               17,706.04
11/1/00      $19.02             136,498.62    $19.02     19,611.21     $19.02               17,706.04
12/1/00      $19.02              61,644.54    $19.02      8,856.67     $19.02                7,996.27
12/15/00     $19.50              76,743.14    $19.50     11,025.94     $19.50                9,954.80
-----------------------------------------------------------------------------------------------------
1/1/01       $19.50             139,943.38    $19.50     20,106.13     $19.50               18,152.88
2/1/01       $19.50             139,943.38    $19.50     20,106.13     $19.50               18,152.88
3/1/01       $19.50             139,943.38    $19.50     20,106.13     $19.50               18,152.88
4/1/01       $19.50             139,943.38    $19.50     20,106.13     $19.50               18,152.88
5/1/01       $19.50             139,943.38    $19.50     20,106.13     $19.50               18,152.88
6/1/01       $19.50             139,943.38    $19.50     20,106.13     $19.50               18,152.88
7/1/01       $19.50             139,943.38    $19.50     20,106.13     $19.50               18,152.88
8/1/01       $19.50             139,943.38    $19.50     20,106.13     $19.50               18,152.88
9/1/01       $19.50             139,943.38    $19.50     20,106.13     $19.50               18,152.88
10/1/01      $19.50             139,943.38    $19.50     20,106.13     $19.50               18,152.88
11/1/01      $19.50             139,943.38    $19.50     20,106.13     $19.50               18,152.88
12/1/01      $19.50              63,200.23    $19.50      9,080.19     $19.50                8,198.07
12/15/01     $19.99              78,671.56    $19.99     11,303.00     $19.99               10,204.95
-----------------------------------------------------------------------------------------------------
1/1/02       $19.99             143,459.90    $19.99     20.611.36     $19.99               18,609.02
2/1/02       $19.99             143,459.90    $19.99     20,611.36     $19.99               18,609.02
2/1/02       $19.99             143,459.90    $19.99     20,611.36     $19.99               18,609.02
4/1/02       $19.99             143,459.90    $19.99     20,611.36     $19.99               18,609.02
5/1/02       $19.99             143,459.90    $19.99     20,611.36     $19.99               18,609.02
6/1/02       $19.99             143,459.90    $19.99     20,611.36     $19.99               18,609.02
7/1/02       $19.99             143,459.90    $19.99     20,611.36     $19.99               18,609.02
8/1/02       $19.99             143,459.90    $19.99     20,611.36     $19.99               18,609.02
9/1/02       $19.99             143,459.90    $19.99     20,611.36     $19.99               18,609.02
10/1/02      $19.99             143,459.90    $19.99     20,611.36     $19.99               18,609.02
11/1/02      $19.99             143,459.90    $19.99     20,611.36     $19.99               18,609.02
12/1/02      $19.99              64,788.34    $19.99      9,308.35     $19.99                8,404.08
=====================================================================================================
</TABLE>
<PAGE>
<TABLE>
<CAPTION>
-----------------------------------------------------------------------------------------------------------------
 Space Name:    Initial 2nd Expansion Space        3rd Expansion Space              4th Expansion Space
 Amendment #    1                                  1                                2
 Square Feet:   6,112                              1,355                            10,652
 Description:   6th Floor                          5th Floor                        2nd Floor
-----------------------------------------------------------------------------------------------------------------
                            Rent       Monthly                 Rent     Monthly                Rent     Monthly
                 Rent/SF  Abatement     Rent       Rent/SF   Abatement   Rent       Rent/SF  Abatement   Rent
-----------------------------------------------------------------------------------------------------------------
<S>             <C>         <C>                    <C>       <C>        <C>        <C>      <C>
6/1/98          $18.10                9,218.93     $18.10              2,043.79     $18.10              16,066.77
7/1/98          $18.10                9,218.93     $18.10              2,043.79     $18.10              16,066.77
8/1/98          $18.10                9,218.93     $18.10              2,043.79     $18.10              16,066.77
9/1/98          $18.10                9,218.93     $18.10              2,043.79     $18.10              16,066.77
10/1/98         $18.10                9,218.93     $18.10              2,043.79     $18.10              16,066.77
11/1/98         $18.10                9,218.93     $18.10              2,043.79     $18.10              16,066.77
12/1/98         $18.10                4,163.39     $18.10                923.00     $18.10               7,255.96
12/15/98        $18.56                5,184.03     $18.56              1,149.27     $18.56               9,034.73
-----------------------------------------------------------------------------------------------------------------
 1/1/99         $18.56                9,453.23     $18.56              2,095.73     $18.56              16,475.09
 2/1/99         $18.56                9,453.23     $18.56              2,095.73     $18.56              16,475.09
 3/1/99         $18.56                9,453.23     $18.56              2,095.73     $18.56              16,475.09
 4/1/99         $18.56                9,453.23     $18.56              2,095.73     $18.56              16,475.09
 5/1/99         $18.56                9,453.23     $18.56              2,095.73     $18.56              16,475.09
 6/1/99         $18.56                9,453.23     $18.56              2,095.73     $18.56              16,475.09
 7/1/99         $18.56                9,453.23     $18.56              2,095.73     $18.56              16,475.09
 8/1/99         $18.56                9,453.23     $18.56              2,095.73     $18.56              16,475.09
 9/1/99         $18.56                9,453.23     $18.56              2,095.73     $18.56              16,475.09
 10/1/99        $18.56                9,453.23     $18.56              2,095.73     $18.56              16,475.09
 11/1/99        $18.56                9,453.23     $18.56              2,095.73     $18.56              16,475.09
 12/1/99        $18.56                4,269.20     $18.56                946.46     $18.56               7,440.36
 12/15/99       $19.02                5,312.51     $19.02              1,177.76     $19.02               9,258.65
-----------------------------------------------------------------------------------------------------------------
 1/1/00         $19.02                9,687.52     $19.02              2,147.68     $19.02              16,883.42
 2/1/00         $19.02                9,687.52     $19.02              2,147.68     $19.02              16,883.42
 3/1/00         $19.02                9,687.52     $19.02              2,147.68     $19.02              16,883.42
 4/1/00         $19.02                9,687.52     $19.02              2,147.68     $19.02              16,883.42
 5/1/00         $19.02                9,687.52     $19.02              2,147.68     $19.02              16,883.42
 6/1/00         $19.02                9,687.52     $19.02              2,147.68     $19.02              16,883.42
 7/1/00         $19.02                9,687.52     $19.02              2,147.68     $19.02              16,883.42
 8/1/00         $19.02                9,687.52     $19.02              2,147.68     $19.02              16,883.42
 9/1/00         $19.02                9,687.52     $19.02              2,147.68     $19.02              16,883.42
 10/1/00        $19.02                9,687.52     $19.02              2,147.68     $19.02              16,883.42
 11/1/00        $19.02                9,687.52     $19.02              2,147.68     $19.02              16,883.42
 12/1/00        $19.02                4,375.01     $19.02                969.92     $19.02               7,624.77
 12/15/00       $19.50                5,446.58     $19.50              1,207.46     $19.50               9,492.31
-----------------------------------------------------------------------------------------------------------------
 1/1/01         $19.50                9,932.00     $19.50              2,201.88     $19.50              17,309.50
 2/1/01         $19.50                9,932.00     $19.50              2,201.88     $19.50              17,309.50
 3/1/01         $19.50                9,932.00     $19.50              2,201.88     $19.50              17,309.50
 4/1/01         $19.50                9,932.00     $19.50              2,201.88     $19.50              17,309.50
 5/1/01         $19.50                9,932.00     $19.50              2,201.88     $19.50              17,309.50
 6/1/01         $19.50                9,932.00     $19.50              2,201.88     $19.50              17,309.50
 7/1/01         $19.50                9,932.00     $19.50              2,201.88     $19.50              17,309.50
 8/1/01         $19.50                9,932.00     $19.50              2,201.88     $19.50              17,309.50
 9/1/01         $19.50                9,932.00     $19.50              2,201.88     $19.50              17,309.50
 10/1/01        $19.50                9,932.00     $19.50              2,201.88     $19.50              17,309.50
 11/1/01        $19.50                9,932.00     $19.50              2,201.88     $19.50              17,309.50
 12/1/01        $19.50                4,485.42     $19.50                994.40     $19.50               7,817.19
 12/15/01       $19.99                5,583.44     $19.99              1,237.82     $19.99               9,730.83
-----------------------------------------------------------------------------------------------------------------
 1/1/02         $19.99               10,181.75     $19.99              2,257.20     $19.99              17,744.46
 2/1/02         $19.99               10,181.75     $19.99              2,257.20     $19.99              17,744.46
 2/1/02         $19.99               10,181.75     $19.99              2,257.20     $19.99              17,744.46
 4/1/02         $19.99               10,181.75     $19.99              2,257.20     $19.99              17,744.46
 5/1/02         $19.99               10,181.75     $19.99              2,257.20     $19.99              17,744.46
 6/1/02         $19.99               10,181.75     $19.99              2,257.20     $19.99              17,744.46
 7/1/02         $19.99               10,181.75     $19.99              2,257.20     $19.99              17,744.46
 8/1/02         $19.99               10,181.75     $19.99              2,257.20     $19.99              17,744.46
 9/1/02         $19.99               10,181.75     $19.99              2,257.20     $19.99              17,744.46
 10/1/02        $19.99               10,181.75     $19.99              2,257.20     $19.99              17,744.46
 11/1/02        $19.99               10,181.75     $19.99              2,257.20     $19.99              17,744.46
 12/1/02        $19.99                4,598.13     $19.99              1,019.38     $19.99               8,013.63
=================================================================================================================
</TABLE>
 <PAGE>
 <TABLE>
<CAPTION>
--------------------------------------------------------------------------------------------
Space Name:           Balance 2nd Expansion Space               5th Expansion Space
Amendment #           3 (5)                                     3
Square Feet:          7,541                                     6,919
Description:          6th Floor                                 2nd Floor
--------------------------------------------------------------------------------------------
                                 Rent      Monthly                          Rent    Monthly
                      Rent/SF  Abatement    Rent                Rent/SF  Abatement    Rent
--------------------------------------------------------------------------------------------
<S>                   <C>     <C>         <C>                   <C>      <C>        <C>
6/1/98                $15.33              9,633.63              $14.68              8,464.24
7/1/98                $15.33              9,633.63              $14.68              8,464.24
8/1/98                $15.33              9,633.63              $14.68              8,464.24
9/1/98                $15.33              9,633.63              $14.68              8,464.24
10/1/98               $15.33              9,633.63              $14.68              8,464.24
11/1/98               $15.33              9,633.63              $14.68              8,464.24
12/1/98               $15.33              4,350.67              $14.68              3,822.56
12/15/98              $15.79              5,441.48              $15.14              4,787.13
--------------------------------------------------------------------------------------------
1/1/99                $15.79              9,922.70              $15.14              8,729.47
2/1/99                $15.79              9,922.70              $15.14              8,729.47
3/1/99                $15.79              9,922.70              $15.14              8,729.47
4/1/99                $15.79              9,922.70              $15.14              8,729.47
5/1/99                $15.79              9,922.70              $15.14              8,729.47
6/1/99                $15.79              9,922.70              $15.14              8,729.47
7/1/99                $15.79              9,922.70              $15.14              8,729.47
8/1/99                $15.79              9,922.70              $15.14              8,729.47
9/1/99                $15.79              9,922.70              $15.14              8,729.47
10/1/99               $15.79              9,922.70              $15.14              8,729.47
11/1/99               $15.79              9,922.70              $15.14              8,729.47
12/1/99               $15.79              4,481.22              $15.14              3,942.34
12/15/99              $16.25              5,600.00              $15.60              4,932.58
--------------------------------------------------------------------------------------------
1/1/00                $16.25             10,211.77              $15.60              8,994.70
2/1/00                $16.25             10,211.77              $15.60              8,994.70
3/1/00                $16.25             10,211.77              $15.60              8,994.70
4/1/00                $16.25             10,211.77              $15.60              8,994.70
5/1/00                $16.25             10,211.77              $15.60              8,994.70
6/1/00                $16.25             10,211.77              $15.60              8,994.70
7/1/00                $16.25             10,211.77              $15.60              8,994.70
8/1/00                $16.25             10,211.77              $15.60              8,994.70
9/1/00                $16.25             10,211.77              $15.60              8,994.70
10/1/00               $16.25             10,211.77              $15.60              8,994.70
11/1/00               $16.25             10,211.77              $15.60              8,994.70
12/1/00               $16.25              4,611.77              $15.60              4,062.12
12/15/00              $16.73              5,765.42              $16.08              5,084.35
--------------------------------------------------------------------------------------------
1/1/01                $16.73             10,513.41              $16.08              9,271.46
2/1/01                $16.73             10,513.41              $16.08              9,271.46
3/1/01                $16.73             10,513.41              $16.08              9,271.46
4/1/01                $16.73             10,513.41              $16.08              9,271.46
5/1/01                $16.73             10,513.41              $16.08              9,271.46
6/1/01                $16.73             10,513.41              $16.08              9,271.46
7/1/01                $16.73             10,513.41              $16.08              9,271.46
8/1/01                $16.73             10,513.41              $16.08              9,271.46
9/1/01                $16.73             10,513.41              $16.08              9,271.46
10/1/01               $16.73             10,513.41              $16.08              9,271.46
11/1/01               $16.73             10,513.41              $16.08              9,271.46
12/1/01               $16.73              4,747.99              $16.08              4,187.11
12/15/01              $17.22              5,934.28              $16.57              5,239.28
--------------------------------------------------------------------------------------------
1/1/02                $17.22             10,821.34              $16.57              9,553.99
2/1/02                $17.22             10,821.34              $16.57              9,553.99
3/1/02                $17.22             10,821.34              $16.57              9,553.99
4/1/02                $17.22             10,821.34              $16.57              9,553.99
5/1/02                $17.22             10,821.34              $16.57              9,553.99
6/1/02                $17.22             10,821.34              $16.57              9,553.99
7/1/02                $17.22             10,821.34              $16.57              9,553.99
8/1/02                $17.22             10,821.34              $16.57              9,553.99
9/1/02                $17.22             10,821.34              $16.57              9,553.99
10/1/02               $17.22             10,821.34              $16.57              9,553.99
11/1/02               $17.22             10,821.34              $16.57              9,553.99
12/1/02               $17.22              4,887.05              $16.57              4,314.70
============================================================================================
</TABLE>
<PAGE>
<TABLE>
<CAPTION>
-----------------------------------------------------------------
Space Name:   6th Expansion Space                       Totals
Amendment #   4
Square Feet:  27,077                                    169,319
Description:  25,027  3rd Floor
               2,050  2nd Floor
-----------------------------------------------------------------
                                                        Total
                         Rent      Monthly              From
              Rent/SF   Abatement    Rent               Detail
-----------------------------------------------------------------
<S>          <C>       <C>        <C>                  <C>
6/1/98        $18.10              40,841.14            251,676.86
7/1/98        $18.10              40,841.14            251,676.86
8/1/98        $18.10              40,841.14            251,676.86
9/1/98        $18.10              40,841.14            251,676.86
10/1/98       $18.10              40,841.14            251,676.86
11/1/98       $18.10              40,841.14            251,676.86
12/1/98       $18.10              18,444.39
12/15/98      $18.56              22,965.95            255,236.20
-----------------------------------------------------------------
1/1/99        $18.56              41,879.09            258,167.42
2/1/99        $18.56              41,879.09            258,167.42
3/1/99        $18.56              41,879.09            258,167.42
4/1/99        $18.56              41,879.09            258,167.42
5/1/99        $18.56              41,879.09            258,167.42
6/1/99        $18.56              41,879.09            258,167.42
7/1/99        $18.56              41,879.09            258,167.42
8/1/99        $18.56              41,879.09            258,167.42
9/1/99        $18.56              41,879.09            258,167.42
10/1/99       $18.56              41,879.09            258,167.42
11/1/99       $18.56              41,879.09            258,167.42
12/1/99       $18.56              18,913.14
12/15/99      $19.02              23,535.15            261,726.76
-----------------------------------------------------------------
1/1/00        $19.02              42,917.05            264,657.99
2/1/00        $19.02              42,917.05            264,657.99
3/1/00        $19.02              42,917.05            264,657.99
4/1/00        $19.02              42,917.05            264,657.99
5/1/00        $19.02              42,917.05            264,657.99
6/1/00        $19.02              42,917.05            264,657.99
7/1/00        $19.02              42,917.05            264,657.99
8/1/00        $19.02              42,917.05            264,657.99
9/1/00        $19.02              42,917.05            264,657.99
10/1/00       $19.02              42,917.05            264,657.99
11/1/00       $19.02              42,917.05            264,657.99
12/1/00       $19.02              19,381.89
12/15/00      $19.50              24,129.10            268,372.08
-----------------------------------------------------------------
1/1/01        $19.50              44,000,13            271,430.75
2/1/01        $19.50              44,000,13            271,430.75
3/1/01        $19.50              44,000,13            271,430.75
4/1/01        $19.50              44,000,13            271,430.75
5/1/01        $19.50              44,000,13            271,430.75
6/1/01        $19.50              44,000,13            271,430.75
7/1/01        $19.50              44,000,13            271,430.75
8/1/01        $19.50              44,000,13            271,430.75
9/1/01        $19.50              44,000,13            271,430.75
10/1/01       $19.50              44,000,13            271,430.75
11/1/01       $19.50              44,000,13            271,430.75
12/1/01       $19.50              19,871.02
12/15/01      $19.99              24,735.42            275,222.22
-----------------------------------------------------------------
1/1/02        $19.99              45,105.77            278,344.61
2/1/02        $19.99              45,105.77            278,344.61
2/1/02        $19.99              45,105.77            278,344.61
4/1/02        $19.99              45,105.77            278,344.61
5/1/02        $19.99              45,105.77            278,344.61
6/1/02        $19.99              45,105.77            278,344.61
7/1/02        $19.99              45,105.77            278,344.61
8/1/02        $19.99              45,105.77            278,344.61
9/1/02        $19.99              45,105.77            278,344.61
10/1/02       $19.99              45,105.77            278,344.61
11/1/02       $19.99              45,105.77            278,344.61
12/1/02       $19.99              20,370.35            125,704.02
=================================================================
</TABLE>