PROMISSORY NOTE

$5,500,000.00                                                   Denver, Colorado
                                                               September 1, 1999

1.       Agreement to Pay. FOR VALUE RECEIVED,  the undersigned,  CAX RIVERSIDE,
         L.L.C., a Delaware limited liability company  (hereinafter  referred to
         as the  "Borrower"),  whose mailing  address is 3410 S. Galena  Street,
         Suite 210, Denver, Colorado 80231, hereby agrees and promises to pay to
         the order of MINNESOTA LIFE INSURANCE COMPANY, a Minnesota corporation,
         its endorsees,  successors and assigns (hereinafter  referred to as the
         "Lender"),  at its principal office and mailing address at c/o Advantus
         Capital Management,  Inc., 400 Robert Street North, St. Paul, Minnesota
         55101-2098,  or such  other  place as the  Lender may from time to time
         designate,  the principal sum of Five Million Five Hundred Thousand and
         00/100 Dollars ($5,500,000.00),  or so much as may from time to time be
         disbursed  hereon,  together  with  interest  on the  unpaid  principal
         balance at the rates  provided  for herein,  payable in lawful money of
         the United States of America which shall be legal tender for public and
         private debts at the time of payment.

2.       Interest  Rate.  The  outstanding  principal  balance hereof shall bear
         interest at the rate of Six and  seven-tenths  percent (6.7%) per annum
         (hereinafter  referred to as the  "Regular  Rate").  Interest  shall be
         computed  on the  basis  of a  three  hundred  sixty  (360)  day  year,
         consisting of twelve (12) successive  thirty (30) day months.  Interest
         for periods of less than one (1) month shall be computed by multiplying
         the monthly  interest  amount as computed  above times a fraction,  the
         numerator of which is the actual  number of days elapsed in said period
         and the  denominator of which is the actual number of days contained in
         the month for which the computation is being made.

3.       Late  Charge.  Any  payment  of  principal,  interest  and/or  tax  and
         insurance  escrows not made by the Borrower within five (5) days of the
         due date  thereof  shall be subject to a late  payment  charge equal to
         four percent (4%) of the  delinquent  payment  amount.  The late charge
         shall  apply  individually  to all  payments  past  due  with no  daily
         adjustment and shall be used to defray the costs of the Lender incident
         to collecting such late payment.  This provision shall not be deemed to
         excuse a late  payment  or be deemed a waiver of any other  rights  the
         Lender  may have  including  the right to  declare  the  entire  unpaid
         principal and interest immediately due and payable.

4.       Default Rate. Upon the occurrence of an Event of Default  hereunder the
         interest  rate shall  thereafter  increase  and shall be payable on the
         whole of the unpaid principal balance at a rate equal to twelve percent
         (12%) per annum (hereinafter  referred to as the "Default Rate"), which
         Default  Rate shall be effective  as of the date of the  occurrence  of
         such Event of Default. The above increase in the interest rate upon the
         occurrence of an Event of Default  shall be  applicable  whether or not
         the Lender has exercised its option to accelerate  the maturity of this
         Note and declared the entire unpaid  principal  indebtedness  to be due
         and  payable.  The  Default  Rate  shall  continue  until such Event of
         Default is cured, payment in full of all indebtedness evidenced by this
         Note, or  completion  of all  foreclosure  proceedings  and  redemption
         periods, whichever shall occur first.
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5.       Monthly  Payments.  Principal and interest upon this Note shall be paid
         as follows:


         a.     Interest  only on the unpaid  principal  balance at the  Regular
                Rate  shall be due and  payable in advance on the date funds are
                disbursed  hereunder in an amount equal to interest accrued from
                and including the date of disbursement hereunder to the last day
                of September, 1999.

         b.     On the first (1st) day of November,  1999,  and on the first day
                of each month  thereafter,  principal and interest  shall be due
                and payable in equal monthly  installments of Forty-One Thousand
                Six Hundred  Fifty-Six  and 68/100  Dollars  ($41,656.68)  until
                October  1,  2019  (hereinafter  referred  to as  the  "Maturity
                Date"),  on  which  date the  entire  unpaid  principal  balance
                together with all accrued  interest,  if not sooner paid,  shall
                become due and payable.

         All payments  shall be applied  first to late charges and  Reinvestment
         Charge and/or  Default  Premium,  as defined below,  if any,  second to
         interest at the rate then in effect under the terms hereof and third to
         principal,  provided however, that if any advance made by the Lender as
         the result of a default on the part of the Borrower  under the terms of
         this Note or any instrument securing this Note is not repaid on demand,
         any monies received,  at the option of the Lender, may first be applied
         to repay such advances,  plus interest thereon at the Default Rate, and
         the balance, if any, shall be applied in accordance with the provisions
         hereof.

6.       Security. This Note is given to evidence a loan in the above amount and
         is the Note referred to in and secured by:

         a.     A  Mortgage  and  Security   Agreement  and  Fixture   Financing
                Statement  (hereinafter  referred to as the "Mortgage") given by
                Borrower, as mortgagor,  to Lender, as mortgagee,  dated of even
                date herewith,  encumbering the Borrower's  interest in the real
                property and all improvements,  fixtures, equipment and personal
                property thereon located in the County of Hillsborough, State of
                Florida (hereinafter referred to as the "Premises"); and

         b.     An  Assignment of Leases and Rents  (hereinafter  referred to as
                the "Assignment of Leases") given by Borrower,  as assignor,  to
                Lender, as assignee,  dated of even date herewith,  assigning to
                Lender  all of the  rents,  issues,  profits  and  leases of the
                Premises; and

         c.     Other collateral security documents  (hereinafter referred to as
                the "Security Documents") given by Borrower to Lender, all dated
                of even date herewith.

         Reference is hereby made to the Mortgage,  the Assignment of Leases and
         the Security  Documents (which are incorporated  herein by reference as
         fully and with the same effect as if set forth  herein at length) for a
         description  of  the  Premises,   a  statement  of  the  covenants  and
         agreements,  a  statement  of the rights and  remedies  and  securities
         afforded thereby and all other matters contained therein.

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7.       Default and  Acceleration.  The  occurrence of an Event of Default,  as
         defined in the Mortgage, shall constitute an Event of Default hereunder
         (hereinafter  referred  to as an "Event of  Default"),  and the  entire
         unpaid principal  balance together with accrued interest at the Default
         Rate shall become,  without notice,  immediately due and payable at the
         option of the Lender. No delay or omission on the part of the Lender in
         exercising any right  hereunder shall operate as a waiver of such right
         or of any other  remedy  under this Note.  A waiver on any one occasion
         shall  not be  construed  as a bar to or  waiver  of any such  right or
         remedy on a future occasion.

8.       Prepayment Privilege.  The indebtedness evidenced hereby may be prepaid
         in accordance with the provisions of this Section 8 and not otherwise.

         a.     For the  purposes  hereof,  the term  "Loan  Year"  shall mean a
                period  consisting of twelve (12) consecutive  months commencing
                on the first  (1st) day of October or any  anniversary  thereof,
                the first  (1st)  Loan Year being the Loan Year  commencing  the
                first (1st) day of October, 1999.

         b.     Prior to the expiration of the fifth (5th) Loan Year no payments
                of principal may be made hereon other than the scheduled monthly
                installment  payments of  principal  and  interest  set forth in
                Section 5 hereof.

         c.     After the  expiration  of the fifth (5th) Loan Year and prior to
                the end of the tenth  (10th) Loan Year,  the Borrower may prepay
                this Note in full but not in part,  provided such  prepayment is
                accompanied by a reinvestment charge (hereinafter referred to as
                the "Reinvestment Charge"). The Reinvestment Charge with respect
                to the  period  commencing  on the first  (1st) day of the sixth
                (6th) Loan Year and expiring on the last day of the tenth (10th)
                Loan  Year  shall  be equal to the  excess,  if any,  of (i) the
                aggregate  present  value as of the date of such  prepayment  of
                each  dollar  of  principal  being  prepaid  and the  amount  of
                interest  that would have been payable in respect of such dollar
                if such prepayment had not been made,  determined by discounting
                such amounts at the Reinvestment  Rate,  defined below, from the
                respective  dates on which they would  have been  payable,  over
                (ii) one hundred percent (100%) of the principal  amount of this
                Note being prepaid.  "Reinvestment Rate" shall mean the yield to
                maturity  of the U.S.  Treasury  Note or Bond  for the  maturity
                (rounded to the nearest  month)  corresponding  to the  weighted
                average life to maturity of the principal  being prepaid or paid
                (as  reported  in the Wall  Street  Journal  on the fifth  (5th)
                business day preceding the date of prepayment).

         d.     The Borrower may prepay this Note,  in full but not in part,  at
                any  time  after  the  tenth  (10th)  Loan  Year  provided  such
                prepayment is accompanied by a Reinvestment  Charge in an amount
                equal to five percent (5%) of the principal  amount prepaid with
                respect to prepayments  made in the eleventh  (11th) and twelfth
                (12th) Loan Years, such Reinvestment Charge thereafter declining
                one percent (1%) during each Loan Year thereafter until the same
                shall be  reduced to one  percent  (1%),  where it shall  remain


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<PAGE>

                until ninety (90) days prior to the Maturity Date.

         e.     The  Borrower  may prepay this Note in full but not in part,  at
                par, and without  payment of a  Reinvestment  Charge  during the
                period commencing ninety (90) days prior to the Maturity Date.

         f.     At the  option  of the  Lender,  this  Note is also  subject  to
                mandatory  prepayment  upon  certain  events  set  forth  in the
                Mortgage including prepayments required by Lender to be made out
                of proceeds of insurance or  condemnation  awards.  In each such
                instance, the terms of the Mortgage shall govern with respect to
                the  requirement  for the  payment of a  Reinvestment  Charge or
                Default Premium.

         g.     Any prepayment  (other than  prepayments  pursuant to Subsection
                8(f) above) shall be made on a regularly  scheduled  installment
                payment date,  shall be made only upon thirty (30) days' advance
                written notice to the Lender,  and all such prepayments shall be
                applied to required monthly installment payments of principal in
                the inverse order of their scheduled due dates.

         h.     Any prepayment of all or any portion of the principal balance of
                this Note made  prior to the end of the fifth  (5th)  Loan Year,
                for  whatever  reason  (other  than   prepayments   pursuant  to
                Subsection 8(f) above), whether voluntary or involuntary,  shall
                constitute  an Event of Default  hereunder,  and, in addition to
                the other  rights and  remedies  provided  for herein and in the
                Mortgage,  the  Assignment  of  Leases  or  any  other  Security
                Document, the Borrower shall be obligated to pay to the Lender a
                default  prepayment  premium  (hereinafter  referred  to as  the
                "Default  Premium")  in an  amount  equal to the sum of (i) four
                percent  (4%) of the amount of  principal  prepaid  and (ii) the
                applicable  Reinvestment  Charge  computed  in  accordance  with
                Section 8(c) above.

9.       Prepayment Upon An Event of Default. Upon the occurrence of an Event of
         Default under this Note and following  acceleration  of maturity hereof
         by the  Lender,  a tender of  payment of or entry of  judgment  for the
         amount  necessary  to  satisfy  the  entire  unpaid  principal  balance
         declared  due and payable  shall be deemed to  constitute  an attempted
         evasion of the aforesaid  restrictions  on the right of prepayment  and
         shall be deemed a  prepayment  hereunder,  and such payment or judgment
         must, therefore,  include the applicable Reinvestment Charge or Default
         Premium   payable  under  the  terms  hereof  in  connection  with  any
         prepayment.

10.      Costs of Collection. The Borrower agrees that if, and as often as, this
         Note is placed in the hands of an attorney for  collection or to defend
         or enforce any of the Lender's rights  hereunder or under the Mortgage,
         the  Assignment  of  Leases  or any other  Security  Document  securing
         payment  of  this  Note,  the  Borrower  will  pay  to the  Lender  its
         attorneys'  fees and all court  costs  (including  attorney's  fees and
         court  costs  prior  to  trial,  at  trial  and  on  appeal,  or in any
         bankruptcy  proceeding)  and  other  expenses  incurred  in  connection
         therewith.

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<PAGE>

11.      Time.  Time is of the  essence of this Note and each of the  provisions
         hereof.

12.      Governing  Law. This Note shall be governed by the laws of the State of
         Florida.

13.      Interest Limitation. All agreements between the Borrower and the Lender
         are  hereby  expressly  limited  so that  in no  contingency  or  event
         whatsoever,  whether  by  reason of  acceleration  of  maturity  of the
         indebtedness  evidenced  hereby or otherwise,  shall the amount paid or
         agreed to be paid to the  Lender for the use,  forbearance,  loaning or
         detention  of the  indebtedness  evidenced  hereby  exceed the  maximum
         permissible under applicable law. If from any circumstances whatsoever,
         fulfillment of any provisions hereof or of the Mortgage,  Assignment of
         Leases or any other  Security  Document at any time given shall  exceed
         the maximum  permissible  under applicable law, then, the obligation to
         be fulfilled shall automatically be reduced to an amount which complies
         with  applicable law, and if from any  circumstances  the Lender should
         ever  receive as  interest  an amount  which  would  exceed the highest
         lawful rate of  interest,  such amount which would be in excess of such
         lawful  rate of  interest  shall be  applied  to the  reduction  of the
         principal  balance evidenced hereby and not to the payment of interest.
         This  provision  shall control every other  provision of all agreements
         between  the  Borrower  and Lender  and shall also be binding  upon and
         available to any subsequent holder of this Note.

14.      Waivers. The Borrower,  endorsers,  sureties,  guarantors and all other
         persons liable for all or any part of the principal  balance  evidenced
         by this Note severally waive presentment for payment,  protest,  notice
         of  nonpayment  and notice of dishonor.  Such parties  hereby  consent,
         without  affecting their  liability,  to any extension or alteration of
         the time or terms of payment hereof, any renewal, any release of any or
         all of the security  given for the payment  hereof,  any  acceptance of
         additional  security of any kind,  and any release of, or resort to any
         party liable for payment hereof.

15.      Disbursement.  Funds  representing  the  proceeds  of the  indebtedness
         evidenced  hereby  which are  disbursed  by the  Lender  by mail,  wire
         transfer or other delivery to the Borrower, to escrows or otherwise for
         the  benefit  of the  Borrower  shall,  for  all  purposes,  be  deemed
         outstanding  hereunder  and to have been received by the Borrower as of
         the date of such mailing,  wire transfer, or delivery and until repaid,
         notwithstanding  the fact that such funds may not at any time have been
         remitted by such escrows to the Borrower or for its benefit.

16.      Captions. The captions to the Sections of this Note are for convenience
         only  and  shall  not be  deemed  part of the  text  of the  respective
         Sections and shall not vary, by  implication  or otherwise,  any of the
         provisions of this Note.

17.      Notices. All notices required or permitted to be given hereunder to the
         Borrower or the Lender shall be given in the manner and to the place as
         provided in the Mortgage for notices to the Mortgagor or the Mortgagee.

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<PAGE>

18.      Due-on-Sale-and-Encumbrance   Provisions.  The  Mortgage  provides  for
         certain  rights  on the  part of the  Lender  to call  all  outstanding
         principal  and  accrued  interest  on this Note due and payable in full
         together with the Reinvestment Charge or Default Premium then in effect
         under  the terms of this Note in the  event  that (a)  Borrower  should
         sell,  convey,  contract  to sell or  convey,  assign or  encumber  any
         property,  real or personal,  encumbered  by the  Mortgage,  or (b) any
         member interests in the Borrower should be sold, conveyed,  assigned or
         encumbered, without, in each instance, the prior written consent of the
         Lender.  Reference to the Mortgage  must be made for the terms of these
         provisions. Such provisions are incorporated herein by this reference.

19.      Partial Non-Recourse to the Borrower.  Notwithstanding  anything to the
         contrary  contained herein, the Borrower shall have no liability to pay
         the outstanding principal balance of this Note or any interest that may
         accrue  thereon,  all such  liability  being  expressly  waived  by the
         Lender,  and the  Lender's  monetary  remedies  under  this  Note,  the
         Mortgage  and  the  Assignment  of  Leases  shall  be  limited  to  the
         Borrower's interest in the Premises and the improvements,  furnishings,
         equipment, leases and rents on which the Mortgage and the Assignment of
         Leases  constitute  a  lien.   Notwithstanding  the  foregoing,  it  is
         expressly  understood  and  agreed  that the  aforesaid  limitation  on
         liability shall in no way effect or apply to the continued liability of
         the Borrower and Commercial Assets,  Inc. for the payment to the Lender
         of: (i) any rents,  issues,  profits or income  which have been prepaid
         more than thirty (30) days in advance; (ii) any rents, issues,  profits
         or  income  collected  by the  Borrower  from the  Premises  after  the
         occurrence  of an Event of Default  under the terms of this  Note,  the
         Mortgage,  the  Assignment of Leases or any other  instrument  securing
         this Note;  (iii)  security  deposits  made by tenants of the Premises;
         (iv)  payments  of all  real  estate  taxes,  special  assessments  and
         insurance  premiums;  (v) insurance  proceeds and condemnation  awards,
         payments and consideration which the Borrower receives and to which the
         Lender is entitled  pursuant to the terms of this Note,  the  Mortgage,
         the Assignment of Leases or of any other instrument securing this Note;
         (vi)   loss  or   damage   suffered   by  the   Lender   arising   from
         misrepresentation  or fraud in  connection  with the loan  evidenced by
         this Note  occurring  as the result of the actions or  inactions of the
         Borrower;  (vii) loss or damage  suffered  by the Lender  occurring  by
         reason of the existence of Hazardous Materials or Wastes, as defined in
         Article 9 of the Mortgage, associated with the Premises or occurring by
         reason of the  failure of the  Borrower  to  observe  and  perform  its
         covenants and  indemnities  respecting the release or discharge of such
         Hazardous  Materials  or Wastes  as set forth in both  Article 9 of the
         Mortgage and in the Indemnity Agreement described in Section 2.9 of the
         Mortgage;  (viii) reasonable  attorney's fees incurred by the Lender as
         provided for in this Note,  the Mortgage,  the  Assignment of Leases or
         any other  instrument  securing this Note;  (ix) damages arising out of
         the  Borrower's  failure  to  comply  with  any  of the  leases  on the
         Premises;  and (x)  damages to the  Premises  from waste  committed  or
         permitted by the Borrower or from a failure by Borrower to maintain the
         Premises  in the  manner  required  by the  terms  of  this  Note,  the
         Mortgage,  the Assignment and all other instruments securing this Note.
         Nothing  contained  herein  shall be deemed to  release  any  entity or
         person,  including the Borrower and Commercial Assets, Inc., from their
         obligations  under the terms of any  separate  Indemnity  Agreement  or
         Guaranty executed in connection with the loan evidenced by this Note.

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20.      WAIVER OF JURY TRIAL. NEITHER LENDER,  BORROWER, ANY GUARANTOR OR OTHER
         PERSON OR ENTITY LIABLE FOR THE INDEBTEDNESS  EVIDENCED HEREBY, NOR ANY
         ASSIGNEE,   SUCCESSOR,  HEIR  OR  PERSONAL  REPRESENTATIVE  OF  LENDER,
         BORROWER, ANY GUARANTOR OR ANY SUCH OTHER PERSON OR ENTITY SHALL SEEK A
         JURY  TRIAL  IN ANY  LAWSUIT,  PROCEEDING,  COUNTERCLAIM  OR ANY  OTHER
         LITIGATION  PROCEDURE  BASED  UPON OR  ARISING  OUT OF THIS  NOTE,  THE
         MORTGAGE,  ANY OTHER OF THE SECURITY DOCUMENTS,  ANY RELATED INSTRUMENT
         OR AGREEMENT,  ANY COLLATERAL FOR THE PAYMENT HEREOF OR THE DEALINGS OR
         THE RELATIONSHIP  BETWEEN OR AMONG SUCH PERSONS OR ENTITIES,  OR ANY OF
         THEM.  NEITHER  LENDER,  BORROWER  NOR ANY  GUARANTOR OR ANY SUCH OTHER
         PERSON OR ENTITY WILL SEEK TO CONSOLIDATE  ANY SUCH ACTION,  IN WHICH A
         JURY TRIAL HAS BEEN WAIVED, WITH ANY OTHER ACTION IN WHICH A JURY TRIAL
         CANNOT BE OR HAS NOT BEEN WAIVED. THE PROVISIONS OF THIS PARAGRAPH HAVE
         BEEN FULLY DISCUSSED BY THE PARTIES HERETO,  AND THE PROVISIONS  HEREOF
         SHALL BE SUBJECT TO NO EXCEPTIONS.  NO PARTY HAS IN ANY WAY AGREED WITH
         OR REPRESENTED TO ANY OTHER PARTY THAT THE PROVISIONS OF THIS PARAGRAPH
         WILL NOT BE FULLY ENFORCED IN ALL INSTANCES.

         IN WITNESS  WHEREOF,  the Borrower has executed this Promissory Note as
of the date and year first above written.

                                     CAX RIVERSIDE, L.L.C.,
                                     a Delaware limited liability company

                                     By:      COMMERCIAL ASSETS, INC.,
                                              a Delaware corporation

                                              By: /s/David M. Becker
                                                 -------------------------------
                                                    David M. Becker
                                              Its:  Chief Financial Officer

                                     Its: Member and Manager

         FLORIDA  DOCUMENTARY  STAMP TAXES REQUIRED TO BE PAID ON ACCOUNT OF THE
INDEBTEDNESS  EVIDENCED  HEREBY  HAVE  BEEN PAID AND THE  DOCUMENTARY  STAMPS SO
PURCHASED HAVE BEEN AFFIXED TO THE MORTGAGE SECURING THIS NOTE.


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