ASSUMPTION AGREEMENT
                              --------------------


         THIS ASSUMPTION  AGREEMENT (the "Assumption  Agreement") is executed as
of this 31st day of December,  1996,  by among  Monterey  Management,  Inc.,  an
Arizona corporation ("MMI"); Monterey Homes Corporation,  an Arizona corporation
("MHC");  Monterey  Management-Tucson,  Inc.,  an Arizona  corporation  ("MMT"),
Monterey   Homes-Tucson   Corporation,   an  Arizona   corporation  ("MHT"  and,
collectively  with MMI,  MHC,  and MM-TI,  the  "Company");  and  Norwest  Bank,
Minnesota,  NA ("Warrant Agent").  Capitalized terms used and not defined herein
shall have the meanings  ascribed to them in the Warrant Agreement (the "Warrant
Agreement"), dated as of October 17, 1994, by and among MMI, MHC and the Warrant
Agent.

                              W I T N E S S E T H:

         WHEREAS,  MMI has  agreed to merge with and into MMT and MHC has agreed
to merge with and into MHT (the "Monterey  Mergers"),  with MMT and MHT assuming
the obligations of MMI and MHC under the Warrant Agreement; and

         WHEREAS,  MMT and MHT have agreed,  subsequent to the Monterey  Mergers
and  subject  to  the  execution  and  delivery  of an  Agreement  and  Plan  of
Reorganization  (the "HPX Merger Agreement") with Homeplex Mortgage  Investments
Corporation,  a Maryland  corporation ("HPX") and satisfaction of the conditions
thereto,  to merge with and into HPX (the "HPX  Merger"),  with HPX assuming the
obligations of MMT and MHT under the Warrant Agreement;

         WHEREAS, pursuant to the HPX Merger Agreement, on the effective date of
the HPX Merger, the Warrants will be converted into warrants ("HPX Warrants") to
purchase shares of HPX common stock,  par value $.01 per share, in an amount and
at an exercise price as set forth herein;

         WHEREAS, pursuant to Section 6.07 of the Warrant Agreement, the parties
hereto  desire to modify the  Warrant  Agreement  to clarify  certain  ambiguous
provisions.

         NOW THEREFORE,  in  consideration  of the foregoing  premises and other
good and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto hereby agree as follows:

                                A G R E E M E N T

         1.  Assumption by MMT and MHT. As of the effective date of the Monterey
Mergers,  MMT and MHT  hereby  expressly  assume all  rights,  responsibilities,
obligations,  and  liabilities  of MMI and MHC under the Warrant  Agreement  and
represent and warrant that MMT and MHT will timely discharge the same.
                                        1

         2.  Effect of  Monterey  Mergers  and  Assumption  by MMT and MHT.  The
parties hereto agree that the Monterey  Mergers will not result in any change in
the overall  stock  ownership or  operations of the Company and are an "internal
reorganization"  as that term is used in Section 2.02 of the Warrant  Agreement.
Consequently,  as a result of the Monterey  Mergers:  (i) the Warrants  will not
become  exercisable or  transferable;  and (ii) no adjustment  will be made with
respect  to the  number of shares of stock or other  securities  covered by each
Warrant,  the number of Warrants  outstanding,  or the Purchase Price at which a
Warrantholder may purchase shares of stock or other securities upon the exercise
of the Warrants.

         3.  Assumption  by HPX.  As of the  Effective  Date  of the HPX  Merger
Agreement  and upon the execution  and delivery of the  acceptance  set forth as
Supplement A hereto (the "HPX Assumption  Date"),  HPX hereby expressly  assumes
all rights, responsibilities,  obligations, and liabilities of MMT and MHT under
the Warrant  Agreement and represents and warrants that it will timely discharge
the same.

         4. Effect of Merger and Assumption by HPX. On the HPX Assumption  Date,
the  Warrants  will be  converted  into HPX  Warrants to purchase  shares of HPX
Common Stock.  The number of shares covered by the HPX Warrants and the Purchase
Price of the HPX Common Stock  issuable upon exercise of the HPX Warrants  shall
be determined as follows:

                  (a) Number of Shares. The number of shares of HPX Common Stock
issuable upon exercise of each HPX Warrant shall be equal to the sum of: (i) the
total  number  of  Exchange  Shares  (as  such  term is  defined  in the  Merger
Agreement) issued in the HPX Merger  (calculated in accordance with the terms of
the HPX Merger  Agreement)  divided by 2,427,776 (the number of shares of Common
Stock of the  Company  outstanding  following  the  Monterey  Mergers on a fully
diluted basis) (the "Warrant Conversion  Ratio");  and (ii) 131,840 (the Warrant
holders'  proportionate share of the 800,000 shares of Contingent Stock (as such
term is defined in the Merger  Agreement) to be issued by HPX in the HPX Merger)
divided by 400,000 (the number of shares issuable upon the exercise of currently
outstanding  Warrants).  The number of shares of HPX Common Stock  issuable upon
exercise of the HPX Warrants shall be subject to further adjustment  pursuant to
Article 3 of the  Warrant  Agreement  with  respect to any events that may occur
after the effective date of the HPX Merger.

                  (b) Purchase  Price.  The  Purchase  Price of each HPX Warrant
will be determined by: (i) subtracting  from the current Purchase Price of $6.25
an amount determined by dividing the Previously Taxed Earnings  Distribution (as
such term is defined in the HPX Merger  Agreement)  by 2,027,776  (the number of
issued and  outstanding  shares of Common  Stock of the  Company  following  the
Monterey Mergers);  (ii) dividing the resulting number by the Warrant Conversion
Ratio; and (iii)  subtracting $.15. This adjusted Purchase Price will be reduced
by an additional $.20 if during the 18 month period following the HPX Merger the
closing  price of the HPX Common Stock on the New York Stock  Exchange  does not
exceed $3.00 per share for five consecutive trading days.
                                        2

         5. Escrowed  Shares.  Upon the HPX Assumption  Date and pursuant to the
HPX Merger Agreement, all Exchange Shares issued in the Merger will be issued in
the name of the Monterey  Stockholders;  provided,  that HPX will hold in escrow
approximately  16.5% of the Exchange  Shares issued in the names of the Monterey
Stockholders  for issuance to Warrant holders upon exercise of the HPX Warrants,
and HPX will remit the Purchase  Price paid upon such  exercises to the Monterey
Stockholders.  Upon  expiration  of  any  unexercised  HPX  Warrants,  HPX  will
distribute the Exchange Shares  underlying such  unexercised HPX Warrants to the
Monterey Stockholders.

         6. Failure to Close  Merger.  In the event that the HPX Merger does not
become  effective,  the Warrants will not be converted  into HPX Warrants and no
adjustment  will be made to the number of shares  covered by the Warrants or the
Purchase  Price of the  Warrants;  provided,  that pursuant to the terms of that
certain  Limited  Guarantee  of  Payment,  dated  as  of ,  1996,  the  Monterey
Stockholders, on or before March 31, 1997, will re-contribute to the Company the
amount of the  Previously  Taxed  Earnings  Distribution  which would exceed the
amount permitted to be distributed under the Indenture relating to the Company's
13% Senior Subordinated Notes Due 2001 (which were issued with the Warrants).

         7.  Clarifications.  Pursuant to Section 6.07 of the Warrant Agreement,
the Warrant  Agent may,  without the  concurrence  of the  Warrant  holders,  by
supplemental  agreement  or  otherwise,  concur  with the  Company in making any
changes or  corrections  to the Warrant  Agreement that are necessary to cure or
correct  any  ambiguity  or  defective  or  inconsistent  provision  or clerical
omission  or  mistake  or  manifest  error  therein  contained  and that are not
prejudicial to the rights of the Warrant holders.  The parties hereto agree that
certain  provisions  of the  Warrant  Agreement  are  ambiguous  and in  need of
clarification and that the Warrant Agreement is modified as follows:

                  (a) Section 3.03 of the Warrant  Agreement,  entitled "When No
Adjustment  Required,"  is hereby  modified to provide  that,  following the HPX
Merger:  (i) any shares of stock issued upon the exercise of options  granted to
HPX officers or employees prior to the Merger will not be counted in determining
whether the aggregate number of shares of stock issued pursuant to any option or
stock  purchase  agreement  entered  into  with  officers  or  employees  of HPX
following the HPX Merger  exceeds 15% of the issued and  outstanding  HPX Common
Stock  as of the date of  adoption  of any such  plans or  agreements;  and (ii)
options  granted to the Monterey  Stockholders  in  connection  with  employment
agreements entered into by HPX and the Monterey  Stockholders  following the HPX
Merger will be counted against the 15% limitation  referred to above only to the
extent that the exercise  price of such options is lower than the Purchase Price
of the HPX Warrants as of the date of such option grants.

                  (b) The Warrant  Agreement is hereby  modified to provide that
the HPX Merger  constitutes the Company's "initial public offering" as that term
is used in the Warrant Agreement.
                                        3

         8. Successors and Assigns.  This Assumption  Agreement shall be binding
on and inure to the benefit of the parties and their  respective  successors and
assigns.

         9. Captions.  The captions of this Assumption  Agreement are solely for
the convenience of reference and shall not affect its interpretation.

         10.  Counterparts.  This Assumption Agreement may be executed in two or
more  counterparts,  each of which shall be deemed an original  but all of which
together shall constitute one and the same instrument.

         11.  Governing Law. This Assumption  Agreement shall be governed by and
interpreted in accordance with the laws of the State of Arizona  (without regard
to conflict of law principles).

         12. No Other Changes.  The parties acknowledge that, except as provided
herein,  all terms of the Warrant  Agreement  remain  unchanged  and are in full
force and effect.



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                                        4

         IN WITNESS WHEREOF, the undersigned, by their duly authorized officers,
have set their hands effective as of the day and year first noted above.

                                        MONTEREY MANAGEMENT, INC.,
                                        an Arizona corporation

                                        By: /s/ Larry W. Seay
                                           -------------------------------
                                        Name: Larry W. Seay
                                             -----------------------------
                                        Title: Vice President
                                              ----------------------------


                                        MONTEREY HOMES CORPORATION,
                                        an Arizona corporation

                                        By: /s/ Larry W. Seay
                                           -------------------------------
                                        Name: Larry W. Seay
                                             -----------------------------
                                        Title: Vice President
                                              ----------------------------


                                        MONTEREY MANAGEMENT-TUCSON, INC.,
                                        an Arizona corporation

                                        By: /s/ Larry W. Seay
                                           -------------------------------
                                        Name: Larry W. Seay
                                             -----------------------------
                                        Title: Vice President
                                              ----------------------------


                                        MONTEREY HOMES-TUCSON CORPORATION,
                                        an Arizona Corporation

                                        By: /s/ Larry W. Seay
                                           -------------------------------
                                        Name: Larry W. Seay
                                             -----------------------------
                                        Title: Vice President
                                              ----------------------------


                                        NORWEST BANK, MINNESOTA, NATIONAL
                                        ASSOCIATION

                                        By: /s/ Raymond S. Hamstadt
                                           -------------------------------
                                        Name: Raymond S. Hamstadt
                                             -----------------------------
                                        Title: Vice President
                                              ----------------------------
                                        5


                                  SUPPLEMENT A
                                  ------------

         Homeplex  Mortgage  Investments  Corporation,  a  Maryland  corporation
("HPX"),  hereby  agrees  that it shall  assume  all  rights,  responsibilities,
obligations,  and  liabilities of Monterey  Management-Tucson,  Inc., an Arizona
corporation  ("MMT"),  and  Monterey   Homes-Tucson   Corporation,   an  Arizona
corporation ("MHT"),  under that certain Warrant Agreement,  dated as of October
17, 1994, by and among Monterey  Management,  Inc., an Arizona  corporation  (as
predecessor  to MMT with  respect to such  Warrant  Agreement),  Monterey  Homes
Corporation,  an Arizona corporation (as predecessor to MHT with respect to such
Warrant  Agreement),  and Norwest  Bank,  Minnesota,  National  Association,  as
Warrant Agent, and further agrees to abide by and be subject to all of the terms
and conditions of the Warrant Agreement, as modified.

DATED this ____ day of ___________________ , 1996.


                                        HOMEPLEX MORTGAGE INVESTMENTS
                                        CORPORATION, a Maryland corporation


                                        By: 
                                           -------------------------------
                                        Name: 
                                             -----------------------------
                                        Title: 
                                              ----------------------------
                                        6