<PAGE>   1
                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                                    FORM 10-Q


[X]  QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE
     ACT OF 1934 FOR THE QUARTERLY PERIOD ENDED MARCH 31, 1999

                                       OR

[ ]  TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES 
     EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM ________ TO ________


                         Commission file number 0-21518

                            IEA INCOME FUND XII, L.P.
             (Exact name of registrant as specified in its charter)


            California                                        94-3143940
 (State or other jurisdiction of                           (I.R.S. Employer
  incorporation or organization)                         Identification No.)

         444 Market Street, 15th Floor, San Francisco, California 94111
         (Address of principal executive offices)           (Zip Code)

                                 (415) 677-8990
              (Registrant's telephone number, including area code)


Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months (or for such shorter period that the registrant was
required to file such reports), and (2) has been subject to such filing
requirements for the past 90 days. Yes [X]. No [ ].

<PAGE>   2

                            IEA INCOME FUND XII, L.P.

                  REPORT ON FORM 10-Q FOR THE QUARTERLY PERIOD
                              ENDED MARCH 31, 1999

                                TABLE OF CONTENTS


<TABLE>
<CAPTION>
                                                                                                  PAGE
                                                                                                  ----
<S>                                                                                               <C>
PART I - FINANCIAL INFORMATION

 Item 1. Financial Statements


         Balance Sheets - March 31, 1999 (unaudited) and December 31, 1998                         4


         Statements of Operations for the three months ended March 31, 1999 and 1998 (unaudited)   5


         Statements of Cash Flows for the three months ended March 31, 1999 and 1998 (unaudited)   6


         Notes to Financial Statements (unaudited)                                                 7


 Item 2. Management's Discussion and Analysis of Financial Condition and Results of Operations    10


 Item 3. Quantitative and Qualitative Disclosures About Market Risk                               11


PART II - OTHER INFORMATION


 Item 1. Legal Proceedings                                                                        12


 Item 3. Defaults Upon Senior Securities                                                          12


 Item 5. Other Information                                                                        12


 Item 6. Exhibits and Reports on Form 8-K                                                         14
</TABLE>



                                       2
<PAGE>   3

                         PART I - FINANCIAL INFORMATION


Item 1.  Financial Statements

         Presented herein are the Registrant's balance sheets as of March 31,
         1999 and December 31, 1998, statements of operations for the three
         months ended March 31, 1999 and 1998, and statements of cash flows for
         the three months ended March 31, 1999 and 1998.



                                       3
<PAGE>   4

                            IEA INCOME FUND XII, L.P.

                                 BALANCE SHEETS

                                   (UNAUDITED)



<TABLE>
<CAPTION>
                                                                               March 31,        December 31,
                                                                                 1999               1998
                                                                             ------------       ------------
<S>                                                                          <C>                <C>         
                 Assets

Current assets:
   Cash and cash equivalents, includes $2,149,241 at March 31, 1999 and
      $2,407,514 at December 31, 1998 in interest-bearing accounts           $  2,149,341       $  2,407,614
   Net lease receivables due from Leasing Company
      (notes 1 and 2)                                                             617,245            656,520
                                                                             ------------       ------------

         Total current assets                                                   2,766,586          3,064,134
                                                                             ------------       ------------

Container rental equipment, at cost                                            62,506,283         62,646,590
   Less accumulated depreciation                                               23,787,568         23,010,870
                                                                             ------------       ------------
      Net container rental equipment                                           38,718,715         39,635,720
                                                                             ------------       ------------

                                                                             $ 41,485,301       $ 42,699,854
                                                                             ============       ============
            Liabilities and Partners' Capital

Current liabilities:
   Accrued expenses                                                          $    462,948       $    462,948
                                                                             ------------       ------------

         Total current liabilities                                                462,948            462,948
                                                                             ------------       ------------

Partners' capital (deficit):
   General partner                                                                (77,043)           (64,897)
   Limited partners                                                            41,099,396         42,301,803
                                                                             ------------       ------------

         Total partners' capital                                               41,022,353         42,236,906
                                                                             ------------       ------------

                                                                             $ 41,485,301       $ 42,699,854
                                                                             ============       ============
</TABLE>


   The accompanying notes are an integral part of these financial statements.



                                       4
<PAGE>   5

                            IEA INCOME FUND XII, L.P.

                            STATEMENTS OF OPERATIONS

                                   (UNAUDITED)



<TABLE>
<CAPTION>
                                                            Three Months Ended
                                                      -----------------------------
                                                       March 31,         March 31, 
                                                         1999              1998
                                                      -----------       -----------
<S>                                                   <C>               <C>        
Net lease revenue (notes 1 and 3)                     $ 1,093,475       $ 1,389,954

Other operating expenses:
  Depreciation                                            915,896           921,226
  Other general and administrative expenses                32,951            28,528
                                                      -----------       -----------
                                                          948,847           949,754
                                                      -----------       -----------

    Earnings from operations                              144,628           440,200

Other income (loss):
  Interest income                                          23,953            27,466
  Net gain (loss) on disposal of equipment                (92,685)            4,496
                                                      -----------       -----------
                                                          (68,732)           31,962
                                                      -----------       -----------

    Net earnings                                      $    75,896       $   472,162
                                                      ===========       ===========

Allocation of net earnings:
  General partner                                     $    48,547       $    62,802
  Limited partners                                         27,349           409,360
                                                      -----------       -----------

                                                      $    75,896       $   472,162
                                                      ===========       ===========

Limited partners' per unit share of net earnings      $      0.01       $      0.12
                                                      ===========       ===========
</TABLE>



   The accompanying notes are an integral part of these financial statements.



                                       5
<PAGE>   6

                            IEA INCOME FUND XII, L.P.

                            STATEMENTS OF CASH FLOWS

                                   (UNAUDITED)


<TABLE>
<CAPTION>
                                                                  Three Months Ended
                                                            -----------------------------
                                                             March 31,         March 31,
                                                               1999              1998
                                                            -----------       -----------
<S>                                                         <C>               <C>        
Net cash provided by operating activities                   $ 1,087,115       $ 1,330,865

Cash flows provided by (used in) investing activities:
  Proceeds from disposal of equipment                           154,371           214,805
  Purchase of container rental equipment                       (199,342)               --
  Acquisition fees paid to general partner                       (9,967)               --
                                                            -----------       -----------

Net cash provided by (used in) investing activities             (54,938)          214,805
                                                            -----------       -----------

Cash flows used in financing activities:
  Distribution to partners                                   (1,290,450)       (1,340,713)
                                                            -----------       -----------


Net increase (decrease) in cash and cash equivalents           (258,273)          204,957


Cash and cash equivalents at January 1                        2,407,614         1,883,389
                                                            -----------       -----------


Cash and cash equivalents at March 31                       $ 2,149,341       $ 2,088,346
                                                            ===========       ===========
</TABLE>


   The accompanying notes are an integral part of these financial statements.



                                       6
<PAGE>   7

                            IEA INCOME FUND XII, L.P.

                     NOTES TO UNAUDITED FINANCIAL STATEMENTS


(1)  Summary of Significant Accounting Policies

     (a) Nature of Operations

         IEA Income Fund XII, L.P. (the "Partnership") is a limited partnership
         organized under the laws of the State of California on August 28, 1991
         for the purpose of owning and leasing marine cargo containers worldwide
         to ocean carriers. To this extent, the Partnership's operations are
         subject to the fluctuations of world economic and political conditions.
         Such factors may affect the pattern and levels of world trade. The
         Partnership believes that the profitability of, and risks associated
         with, leases to foreign customers is generally the same as those of
         leases to domestic customers. The Partnership's leases generally
         require all payments to be made in United States currency.

         Cronos Capital Corp. ("CCC") is the general partner and, with its
         affiliate Cronos Containers Limited (the "Leasing Company"), manages
         the business of the Partnership. The Partnership shall continue until
         December 31, 2011, unless sooner terminated upon the occurrence of
         certain events.

         The Partnership commenced operations on January 31, 1992, when the
         minimum subscription proceeds of $2,000,000 were obtained. The
         Partnership offered 3,750,000 units of limited partnership interest at
         $20 per unit, or $75,000,000. The offering terminated on November 30,
         1992, at which time 3,513,594 limited partnership units had been
         purchased.

     (b) Leasing Company and Leasing Agent Agreement

         The Partnership has entered into a Leasing Agent Agreement whereby the
         Leasing Company has the responsibility to manage the leasing operations
         of all equipment owned by the Partnership. Pursuant to the Agreement,
         the Leasing Company is responsible for leasing, managing and re-leasing
         the Partnership's containers to ocean carriers and has full discretion
         over which ocean carriers and suppliers of goods and services it may
         deal with. The Leasing Agent Agreement permits the Leasing Company to
         use the containers owned by the Partnership, together with other
         containers owned or managed by the Leasing Company and its affiliates,
         as part of a single fleet operated without regard to ownership. Since
         the Leasing Agent Agreement meets the definition of an operating lease
         in Statement of Financial Accounting Standards (SFAS) No. 13, it is
         accounted for as a lease under which the Partnership is lessor and the
         Leasing Company is lessee.

         The Leasing Agent Agreement generally provides that the Leasing Company
         will make payments to the Partnership based upon rentals collected from
         ocean carriers after deducting direct operating expenses and management
         fees to CCC and the Leasing Company. The Leasing Company leases
         containers to ocean carriers, generally under operating leases which
         are either master leases or term leases (mostly one to five years).
         Master leases do not specify the exact number of containers to be
         leased or the term that each container will remain on hire but allow
         the ocean carrier to pick up and drop off containers at various
         locations; rentals are based upon the number of containers used and the
         applicable per-diem rate. Accordingly, rentals under master leases are
         all variable and contingent upon the number of containers used. Most
         containers are leased to ocean carriers under master leases; leasing
         agreements with fixed payment terms are not material to the financial
         statements. Since there are no material minimum lease rentals, no
         disclosure of minimum lease rentals is provided in these financial
         statements.


                                                                     (Continued)



                                       7
<PAGE>   8

                            IEA INCOME FUND XII, L.P.

                     NOTES TO UNAUDITED FINANCIAL STATEMENTS



     (c) Basis of Accounting

         The Partnership utilizes the accrual method of accounting. Net lease
         revenue is recorded by the Partnership in each period based upon its
         leasing agent agreement with the Leasing Company. Net lease revenue is
         generally dependent upon operating lease rentals from operating lease
         agreements between the Leasing Company and its various lessees, less
         direct operating expenses and management fees due in respect of the
         containers specified in each operating lease agreement.

     (d) Financial Statement Presentation

         These financial statements have been prepared without audit. Certain
         information and footnote disclosures normally included in financial
         statements prepared in accordance with generally accepted accounting
         procedures have been omitted. It is suggested that these financial
         statements be read in conjunction with the financial statements and
         accompanying notes in the Partnership's latest annual report on Form
         10-K.

         The preparation of financial statements in conformity with generally
         accepted accounting principles (GAAP) requires the Partnership to make
         estimates and assumptions that affect the reported amounts of assets
         and liabilities and disclosure of contingent assets and liabilities at
         the date of the financial statements and the reported amounts of
         revenues and expenses during the reported period. Actual results could
         differ from those estimates.

         The interim financial statements presented herewith reflect all
         adjustments of a normal recurring nature which are, in the opinion of
         management, necessary to a fair statement of the financial condition
         and results of operations for the interim periods presented.


(2)  Net Lease Receivables Due from Leasing Company

     Net lease receivables due from the Leasing Company are determined by
     deducting direct operating payables and accrued expenses, base management
     fees payable, and reimbursed administrative expenses payable to CCC and its
     affiliates from the rental billings payable by the Leasing Company to the
     Partnership under operating leases to ocean carriers for the containers
     owned by the Partnership. Net lease receivables at March 31, 1999 and
     December 31, 1998 were as follows:


<TABLE>
<CAPTION>
                                                                      March 31,       December 31,
                                                                         1999            1998 
                                                                      ----------      ----------
<S>                                                                   <C>             <C>       
         Lease receivables, net of doubtful accounts of $157,141
           at March 31, 1999 and $209,635 at December 31, 1998        $1,691,135      $1,690,827
         Less:
         Direct operating payables and accrued expenses                  543,806         491,270
         Damage protection reserve                                       235,054         237,855
         Base management fees                                            262,164         271,288
         Reimbursed administrative expenses                               32,866          33,894
                                                                      ----------      ----------

                                                                      $  617,245      $  656,520
                                                                      ==========      ==========
</TABLE>


                                                                     (Continued)



                                       8
<PAGE>   9

                            IEA INCOME FUND XII, L.P.

                     NOTES TO UNAUDITED FINANCIAL STATEMENTS


(3)  Net Lease Revenue

     Net lease revenue is determined by deducting direct operating expenses,
     base management fees and reimbursed administrative expenses to CCC and its
     affiliates from the rental revenue billed by the Leasing Company under
     operating leases to ocean carriers for the containers owned by the
     Partnership. Net lease revenue for the three-month periods ended March 31,
     1999 and 1998 was as follows:


<TABLE>
<CAPTION>
                                                      Three Months Ended
                                                  --------------------------
                                                   March 31,       March 31,
                                                     1999            1998
                                                  ----------      ----------
<S>                                               <C>             <C>       
         Rental revenue (note 4)                  $1,862,426      $2,179,358
         Less:
         Rental equipment operating expenses         537,698         487,720
         Base management fees                        128,266         149,902
         Reimbursed administrative expenses          102,987         151,782
                                                  ----------      ----------

                                                  $1,093,475      $1,389,954
                                                  ==========      ==========
</TABLE>


(4)  Operating Segment

     The Financial Accounting Standards Board has issued SFAS No. 131,
     "Disclosures about Segments of an Enterprise and Related Information",
     which changes the way public business enterprises report financial and
     descriptive information about reportable operating segments. An operating
     segment is a component of an enterprise that engages in business activities
     from which it may earn revenues and incur expenses, whose operating results
     are regularly reviewed by the enterprise's chief operating decision maker
     to make decisions about resources to be allocated to the segment and assess
     its performance, and about which separate financial information is
     available. Management operates the Partnership's container fleet as a
     homogenous unit and has determined, after considering the requirements of
     SFAS No. 131, that as such it has a single reportable operating segment.

     The Partnership derives its revenues from owning and leasing marine cargo
     containers. As of March 31, 1999, the Partnership operated 9,314
     twenty-foot, 5,207 forty-foot and 205 forty-foot high-cube marine dry cargo
     containers, as well as 195 twenty-foot and 305 forty-foot marine
     refrigerated cargo containers. A summary of gross lease revenue, by
     product, for the three-month periods ended March 31, 1999 and 1998 follows:

<TABLE>
<CAPTION>
                                                         1999            1998
                                                      ----------      ----------
<S>                                                   <C>             <C>       
         Dry cargo containers                         $1,489,917      $1,765,023
         Refrigerated containers                         372,509         414,335
                                                      ----------      ----------

         Total                                        $1,862,426      $2,179,358
                                                      ==========      ==========
</TABLE>

     Due to the Partnership's lack of information regarding the physical
     location of its fleet of containers when on lease in the global shipping
     trade, it is impracticable to provide the geographic area information
     required by SFAS No. 131. Any attempt to separate "foreign" operations from
     "domestic" operations would be dependent on definitions and assumptions
     that are so subjective as to render the information meaningless and
     potentially misleading.





                                       9
<PAGE>   10

Item 2.  Management's Discussion and Analysis of Financial Condition and Results
         of Operations

It is suggested that the following discussion be read in conjunction with the
Registrant's most recent annual report on Form 10-K.

1)   Material changes in financial condition between March 31, 1999 and December
     31, 1998.

     At March 31, 1999, the Registrant had $2,149,341 in cash and cash
     equivalents, a decrease of $258,273 from the cash balances at December 31,
     1998. During the first quarter of 1999, the Registrant expended $209,309 of
     cash generated from sales proceeds to purchase and replace containers which
     had been lost or damaged beyond repair.

     The Registrant's operating performance contributed to a 6% decline in net
     lease receivables at March 31, 1999 when compared to December 31, 1998. The
     Registrant's cash distribution from operations for the first quarter of
     1999 was 6.50% (annualized) of the limited partners' original capital
     contributions, unchanged from the fourth quarter of 1998. These
     distributions are directly related to the Registrant's results from
     operations and may fluctuate accordingly. The cash distribution from sales
     proceeds for the first quarter of 1999 was .50% (annualized) of the limited
     partners' original capital contribution, unchanged from the fourth quarter
     of 1998. Sales proceeds to its partners may fluctuate in subsequent
     periods, reflecting the level of container disposals.

     Growth in intra-Asian trade and improving lease-out activity in some key
     locations have expanded the requirement for leased containers in selected
     locations. As a result of these slowly improving trends, trade volumes in
     several markets are rebounding and utilization of the Registrant's
     equipment has been recently improving. However, per-diem rental rates
     remain unchanged and container imbalances are expected to continue for the
     remainder of 1999. In light of the encouraging signs mentioned above, the
     Registrant will selectively increase its repositioning of available
     equipment to higher demand locations when it believes that the impact will
     have a positive effect on operations.

2)   Material changes in the results of operations between the three-month
     period ended March 31, 1999 and the three-month period ended March 31,
     1998.

     Net lease revenue for the three-month period ended March 31, 1999 was
     $1,093,475, a decline of 21% from the same period in the prior year. Gross
     rental revenue (a component of net lease revenue) for the three-month
     period ended March 31, 1999 was $1,862,426, reflecting a decline of 15%
     from the same period in the prior year. Gross lease revenue was primarily
     impacted by lower per-diem rental rates and utilization levels. Average dry
     cargo container per-diem rental rates for the three-month period ended
     March 31, 1999 declined approximately 4%, when compared to the same period
     in the prior year. Average refrigerated container per-diem rental rates for
     the three-month period ended March 31, 1999 declined approximately 6%, when
     compared to the same period in the prior year.

     The Registrant's average fleet size and utilization rates for the
     three-month periods ended March 31, 1999 and 1998 were as follows:

<TABLE>
<CAPTION>
                                                           Three Months Ended
                                                         ----------------------
                                                         March 31,    March 31,
                                                           1999         1998
                                                         ---------    ---------
<S>                                                      <C>          <C>   
         Average fleet size (measured in twenty-foot
            equivalent units (TEU))
               Dry cargo containers                       20,135       20,277
               Refrigerated containers                       807          809
         Average Utilization
               Dry cargo containers                           66%          78%
               Refrigerated containers                        69%          85%
</TABLE>



                                       10
<PAGE>   11

     Rental equipment operating expenses were 29% of the Registrant's gross
     lease revenue during the three-month period ended March 31, 1999, as
     compared to 22% during the three-month period ended March 31, 1998. This
     increase was largely attributable to an increase in costs associated with
     lower utilization levels, including handling and storage.

     The Registrant disposed of 56 twenty-foot, 34 forty-foot and one forty-foot
     high-cube marine dry cargo containers during the first quarter of 1999, as
     compared to 25 twenty-foot, 17 forty-foot and one forty-foot high-cube
     marine dry cargo containers during the same period in the prior year. The
     decision to repair or dispose of a container is made when it is returned by
     a lessee. This decision is influenced by various factors including the age,
     condition, suitability for continued leasing, as well as the geographical
     location of the container when disposed. These factors also influence the
     amount of sales proceeds received and the related gain on container
     disposals.


     Year 2000

     The Registrant relies upon the financial and operational systems provided
     by the Leasing Company and its affiliates, as well as the systems provided
     by other independent third parties to service the three primary areas of
     its business: investor processing/maintenance; container leasing/asset
     tracking; and accounting finance. The Registrant has received confirmation
     from its third-party investor processing/maintenance vendor that their
     system is Year 2000 compliant. The Registrant does not expect a material
     increase in its vendor servicing fee to reimburse Year 2000 costs.
     Container leasing/asset tracking and accounting/finance services are
     provided to the Registrant by CCC and its affiliate, the Leasing Company,
     pursuant to the respective Limited Partnership Agreement and Leasing Agent
     Agreement. CCC and the Leasing Company have initiated a program to prepare
     their systems and applications for the Year 2000. Preliminary studies
     indicate that testing, conversion and upgrading of system applications is
     expected to cost CCC and the Leasing Company less than $500,000. Pursuant
     to the Limited Partnership Agreement, CCC or the Leasing Company, may not
     seek reimbursement of data processing costs associated with the Year 2000
     program. The financial impact of making these required system changes is
     not expected to be material to the Registrant's financial position, results
     of operations or cash flows.

     Cautionary Statement

     This Quarterly Report on Form 10-Q contains statements relating to future
     results of the Registrant, including certain projections and business
     trends, that are "forward-looking statements" as defined in the Private
     Securities Litigation Reform Act of 1995. Actual results may differ
     materially from those projected as a result of certain risks and
     uncertainties, including but not limited to changes in: economic
     conditions; trade policies; demand for and market acceptance of leased
     marine cargo containers; competitive utilization and per-diem rental rate
     pressures; as well as other risks and uncertainties, including but not
     limited to those described above in the discussion of the marine container
     leasing business under Item 2., Management's Discussion and Analysis of
     Financial Condition and Results of Operations; and those detailed from time
     to time in the filings of the Registrant with the Securities and Exchange
     Commission.


Item 3. Quantitative and Qualitative Disclosures About Market Risk

        Not applicable.



                                       11
<PAGE>   12

                           PART II - OTHER INFORMATION

Item 1.  Legal Proceedings

         As reported in the Registrant's Current Report on Form 8-K and
         Amendment No. 1 to Current Report on Form 8-K, filed with the
         Commission on February 7, 1997 and February 26, 1997, respectively,
         Arthur Andersen, London, England, resigned as auditors of The Cronos
         Group, (the "Parent Company"), on February 3, 1997.

         The Parent Company is the indirect corporate parent of CCC, the general
         partner of the Registrant. In its letter of resignation to the Parent
         Company, Arthur Andersen stated that it resigned as auditors of the
         Parent Company and all other entities affiliated with the Parent
         Company. While its letter of resignation was not addressed to CCC,
         Arthur Andersen confirmed to CCC that its resignation as auditors of
         the entities referred to in its letter of resignation included its
         resignation as auditors of CCC and the Registrant.

         CCC does not believe, based upon the information currently available to
         it, that Arthur Andersen's resignation was triggered by any concern
         over the accounting policies and procedures followed by the Registrant.

         Arthur Andersen's reports on the financial statements of CCC and the
         Registrant, for years preceding 1996, had not contained an adverse
         opinion or a disclaimer of opinion, nor were any such reports qualified
         or modified as to uncertainty, audit scope, or accounting principles.

         During the Registrant's fiscal year ended December 31, 1995 and the
         subsequent interim period preceding Arthur Andersen's resignation,
         there were no disagreements between CCC or the Registrant and Arthur
         Andersen on any matter of accounting principles or practices, financial
         statement disclosure, or auditing scope or procedure.

         In connection with its resignation, Arthur Andersen also prepared a
         report pursuant to the provisions of Section 10A(b)(2) of the
         Securities Exchange Act of 1934, as amended, for filing by the Parent
         Company with the Securities and Exchange Commission (the "SEC").
         Following the report of Arthur Andersen, the SEC, on February 10, 1997,
         commenced a private investigation of the Parent Company for the purpose
         of investigating the matters discussed in such report and related
         matters. The Registrant does not believe that the focus of the SEC's
         investigation is upon the Registrant or CCC. CCC is unable to predict
         the outcome of the SEC's ongoing private investigation of the Parent
         Company.


Item 3.  Defaults Upon Senior Securities

         See Item 5.  Other Information.


Item 5.  Other Information

         In 1993, the Parent Company negotiated a credit facility (hereinafter,
         the "Credit Facility") with several banks for the use by the Parent
         Company and its subsidiaries, including CCC. At December 31, 1996,
         approximately $73,500,000 in principal indebtedness was outstanding
         under the Credit Facility. As a party to the Credit Facility, CCC is
         jointly and severally liable for the repayment of all principal and
         interest owed under the Credit Facility. The obligations of CCC, and
         the five other subsidiaries of the Parent Company that are borrowers
         under the Credit Facility, are guaranteed by the Parent Company.



                                       12
<PAGE>   13

         Following negotiations in 1997 with the banks providing the Credit
         Facility, an Amended and Restated Credit Agreement was executed in June
         1997, subject to various actions being taken by the Parent Company and
         its subsidiaries, primarily relating to the provision of additional
         collateral. This Agreement was further amended in July 1997 and the
         provisions of the Agreement and its Amendment converted the facility to
         a term loan, payable in installments, with a final maturity date of May
         31, 1998. The terms of the Agreement and its Amendment also provided
         for additional security over shares in the subsidiary of the Parent
         Company that owns the head office of the Parent Company's container
         leasing operations. They also provided for the loans to the former
         Chairman of $5,900,000 and $3,700,000 to be restructured as obligations
         of the former Chairman to another subsidiary of the Parent Company (not
         CCC), together with the pledge to this subsidiary company of 2,030,303
         Common Shares beneficially owned by him in the Parent Company as
         security for these loans. They further provided for the assignment of
         these loans to the lending banks, together with the pledge of 1,000,000
         shares and the assignment of the rights of the Parent Company in
         respect of the other 1,030,303 shares. Additionally, CCC granted the
         lending banks a security interest in the fees to which it is entitled
         for the services it renders to the container leasing partnerships of
         which it acts as general partner, including its fee income payable by
         the Registrant. The Parent Company did not repay the Credit Facility at
         the amended maturity date of May 31, 1998.

         On June 30, 1998, the Parent Company entered into a third amendment
         (the "Third Amendment") to the Credit Facility. Under the Third
         Amendment, the remaining principal amount of $36,800,000 was to be
         amortized in varying monthly amounts commencing on July 31, 1998 with
         $26,950,000 due on September 30, 1998 and a final maturity date of
         January 8, 1999. The Parent Company did not repay the amounts due on
         September 30, 1998 and January 8, 1999. The balance outstanding on the
         Credit Facility at December 31, 1998 was $33,110,000.

         In March 1999, the Parent Company agreed to a fourth amendment (the
         "Fourth Amendment") to the Bank Facility under which the final maturity
         date will be September 1999. The Fourth Amendment became effective as
         of March 31, 1999 subject to the satisfaction thereafter of various
         conditions, including the delivery of the Parent Company's audited
         financial statements for 1998, together with various legal opinions and
         other loan documentation by April 15, 1999. This date was extended to
         April 30, 1999. The Parent Company furnished the required legal
         opinions and other loan documentation and are now under review.

         The directors of the Parent Company also are pursuing alternative
         sources of financing to meet the amended repayment obligations
         anticipated under the Fourth Amendment. Failure to meet revised lending
         terms would constitute an event of default with the lenders. The
         declaration of an event of default would result in further defaults
         with other lenders under loan agreement cross-default provisions.
         Should a default of the term loans be enforced, the Parent Company and
         CCC may be unable to continue as going concerns.

         The Registrant is not a borrower under the Credit Facility, and neither
         the containers nor the other assets of the Registrant have been pledged
         as collateral under the Credit Facility.

         CCC is unable to determine the impact, if any, these issues may have on
         the future operating results, financial condition and cash flows of the
         Registrant or CCC and on the Leasing Company's ability to manage the
         Registrant's fleet in subsequent periods.



                                       13
<PAGE>   14

Item 6.  Exhibits and Reports on Form 8-K

(a)  Exhibits

<TABLE>
<CAPTION>
      Exhibit
        No.                       Description                                 Method of Filing
     ---------   ----------------------------------------------------   ----------------------------
<S>              <C>                                                    <C>
       3(a)      Limited Partnership Agreement of the Registrant,          *
                 amended and restated as of December 2, 1991

       3(b)      Certificate of Limited Partnership of the Registrant      **

       10        Form of Leasing Agent Agreement with Cronos               ***
                 Containers Limited

       27        Financial Data Schedule                                   Filed with this document
</TABLE>


(b)  Reports on Form 8-K

     No reports on Form 8-K were filed by the Registrant during the quarter
ended March 31, 1999.



--------

*       Incorporated by reference to Exhibit "A" to the Prospectus of the
        Registrant dated December 2, 1991, included as part of Registration
        Statement on Form S-1 (No. 33-42697)

**      Incorporated by reference to Exhibit 3.2 to the Registration Statement
        on Form S-1 (No. 33-42697)

***     Incorporated by reference to Exhibit 10.2 to the Registration Statement
        on Form S-1 (No. 33-42697)



                                       14
<PAGE>   15

                                   SIGNATURES



        Pursuant to the requirements of the Securities Exchange Act of 1934, the
Registrant has duly caused this Report to be signed on its behalf by the
undersigned thereunto duly authorized.


                                        IEA INCOME FUND XII, L.P.


                                        By   Cronos Capital Corp.
                                             The General Partner




                                        By   /s/ Dennis J. Tietz
                                             -----------------------------------
                                             Dennis J. Tietz
                                             President and Director of Cronos
                                             Capital Corp. ("CCC") Principal 
                                             Executive Officer of CCC



Date: May 15, 1999



                                       15
<PAGE>   16

                                  EXHIBIT INDEX



<TABLE>
<CAPTION>
      Exhibit
        No.                       Description                                 Method of Filing
     ---------   ----------------------------------------------------   ----------------------------
<S>              <C>                                                    <C>
       3(a)      Limited Partnership Agreement of the Registrant,          *
                 amended and restated as of December 2, 1991

       3(b)      Certificate of Limited Partnership of the Registrant      **

       10        Form of Leasing Agent Agreement with Cronos               ***
                 Containers Limited

       27        Financial Data Schedule                                   Filed with this document
</TABLE>



----------

*       Incorporated by reference to Exhibit "A" to the Prospectus of the
        Registrant dated December 2, 1991, included as part of Registration
        Statement on Form S-1 (No. 33-42697)

**      Incorporated by reference to Exhibit 3.2 to the Registration Statement
        on Form S-1 (No. 33-42697)

***     Incorporated by reference to Exhibit 10.2 to the Registration Statement
        on Form S-1 (No. 33-42697)