<PAGE>
 
                                                                   EXHIBIT 10.50

                                LOAN AGREEMENT
                                --------------

The First National Bank of Chicago, Hong Kong Branch (the "Bank"), whose address
is 13/F Jardine House, 1 Connaught Place, Central, Hong Kong, agrees to extend 
the credit facility described below to CellStar (Asia) Corporation Limited (the 
"Borrower"), whose address is Rooms 509-510, 5/F, Block B, Sing Tao Building, 1 
Wang Kwong Road, Kowloon bay, Kowloon, Hong Kong, under the terms and conditions
set forth in this agreement (the "Agreement").

1.   CREDIT FACILITY
     ---------------

     The Bank agrees to extend the following credit facility to the Borrower, 
     CellStar (Asia) Corporation Limited:


     A United States Dollar Fifteen Million (US$15,000,000) revolving credit
     (the "Credit Facility") maturing July 31, 1997, the proceeds of which will
     be used for general working capital purposes and to negotiate export
     commercial letters of credit which may contain discrepancies whereby the
     Bank maintains full recourse to the Borrower.

2.   CONDITIONS PRECEDENT
     --------------------

     The Borrower shall provide the Bank the following documents prior to the 
     extension of the Credit Facility:

     (a)  A copy of a Board Resolution of the Borrower authorizing the Borrower
          to enter into this Agreement and appointing authorized persons to sign
          all applications, notices and documents to be delivered hereunder.

     (b)  Specimen signatures of the authorized persons under the Board 
          resolution referred to in section 2(b) above.

     (c)  A copy of this Agreement duly executed by the Borrower.

     (d)  Corporate guarantees of CellStar Corporation, and National Auto
          Center, Inc. (the "Guarantors").

     (e)  Board resolutions authorizing CellStar Corporation and National Auto 
          Center, Inc. to guarantee the Credit Facility.

     (f)  Copy of hazard and theft insurance policy covering inventory 
          maintained by Borrower.

     (g)  Such other documents as the Bank may reasonably require.

3.   INTEREST RATES
     --------------

     Interest rates charged to the Borrower under the Credit Facility are based
     on the interest rate pricing grids as defined in the National Auto Center,
     Inc. credit facility ("Domestic Facility") which is attached as Exhibit A.

     The Borrower agrees to pay the Bank interest calculated on a daily basis
     and at the rates specified below on all amounts outstanding under the
     Credit Facility. Interest will be calculated on the basis of actual days
     elapsed in a year of 360 days. All payments will be applied first to
     accrued interest, then to principal.

                            /s/JAS          /s/AHG
                         ------------    ------------
                            INITIAL         INITIAL
                            (Bank)         (Borrower)
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                                       2

     (a)  At Borrowers Option:
          -------------------

          1.   Texas Commerce Bank's (Agent) Base Rate (greater of Agent's
               "Prime Rate" or Fed Funds Rate plus 1/2%) plus applicable margin
               as defined in the Domestic Facility.

          2.   Eurodollar rate (1, 2 or 3 month) plus applicable margin as 
               defined in the Domestic Facility.

     (b)  Default Interest Rate:
          ---------------------

          In addition to the interest specified above, default interest shall be
          chargeable to the Borrower from the date of any default at an
          additional two percent (2%) per annum on all amounts outstanding.

4.   COMMITMENT FEE
     --------------

     The Borrower agrees to pay the Bank a fee of 0.5 percent (50 basis points)
     per annum on the unused portion of the Credit Facility. The commitment fee
     will be calculated on a daily basis and will be payable quarterly in
     arrears.

5.   UPFRONT FEE
     -----------

     0.35 percent (35 basis points) on the amount of the Credit Facility or 
     US$52,500.

6.   COLLATERAL
     ----------

     The Bank will file with the Registrar of Companies in Hong Kong a floating
     charge on the Borrower's trade accounts receivable and inventory contained
     in a debenture to be executed by the Borrower in favor of the Bank.

7.   BORROWING BASE
     --------------

     Notwithstanding any other provisions of this Agreement, the aggregate
     principal amount outstanding at any one time under the Credit Facility
     shall not exceed the lesser of the Borrowing Base or US$15,000,000.

     Borrowing Base means:

     Eighty percent* of the Borrower's trade accounts receivable in which the
     Bank has a perfected, first priority security interest, excluding accounts
     more than ninety days past due from the date of invoice, accounts subject
     to offset or defense, bonded, affiliate accounts and accounts otherwise
     reasonably unacceptable to the Bank plus:

     Ninety percent of bills receivable under commercial letters of credit
     issued by banks for which the Bank has approved credit limits, and not
     exceeding ninety days plus:

     Fifty percent of the Borrower's inventory in which the Bank has a
     perfected, first priority security interest, net of any obsolescence
     reserve, slow moving or inventory in transit.

     *    Advance rate against trade accounts receivable is reduced to seventy
          percent on any individual account which has a month end balance
          greater than twenty-five percent of the sum of the acceptable account
          balances at that same month end.

                            /s/JAS          /s/AHG
                         ------------    ------------
                            INITIAL         INITIAL
                            (Bank)         (Borrower)
<PAGE>
 
                                       3

8.   GUARANTY
     --------

     Payment of the Borrower under this Credit Facility shall be guaranteed by
     CellStar Corporation and National Auto Center, Inc. (the "Guarantors") by
     execution of the Bank's form of guaranty agreement.

9.   AFFIRMATIVE COVENANTS
     ---------------------

     So long as there is any outstanding under the Credit Facility, the Borrower
     shall:

     (a)  maintain insurance with financially sound and reputable insurers
          covering its properties and business against those casualties and
          contingencies and in the types and amounts as shall be in accordance
          with sound business and industry practices.

     (b) maintain its existence and business operations presently in effect in
         accordance with all applicable laws and regulations, pay its debts and
         obligations when due under normal terms (which, for the avoidance of
         doubt shall not limit or restrict the Borrower in accepting trade
         credit from its suppliers on normal commercial terms), and pay on or
         before their due date, all taxes, assessments, fees and other
         governmental monetary obligations, except as they may be contested in
         good faith if they have been properly reflected on its books and, at
         the Bank's request, adequate funds or security has been pledged to
         insure payment.

     (c) maintain proper books and records of account, in accordance with
         generally accepted accounting principles where applicable, and
         consistent with financial statements previously submitted to the Bank.

     (d) furnish to the bank whatever information, books and records the Bank
         may reasonably request, including at a minimum:

         (i)   annual audited financial statements of the Borrower and the
               Guarantors, and

         (ii)  monthly internally prepared financial statements of the Borrower.

         (iii) monthly computer generated account receivable aging/report.

         (iv)  monthly computer generated inventory report.

         (v)   monthly borrowing base report.

         (vi)  quarterly covenant compliance certificate.


10.  NEGATIVE COVENANTS
     ------------------

     (a) Definitions:
          
         As used in this Agreement, the following terms shall have the 
         following respective meanings:

         (i)  "Tangible Net Worth" shall mean total assets less intangible
              assets and total liabilities. Intangible assets include goodwill,
              patents, copyrights, mailing lists, catalogs, trademarks, bond
              discounts and underwriting expenses, organization expenses, and
              all other intangibles.


                            /s/JAS          /s/AHG
                         ------------    ------------
                            INITIAL         INITIAL
                            (Bank)         (Borrower)

<PAGE>
 
                                       4


          (ii)   Unless otherwise noted, the financial requirements set forth in
                 this Section 10 shall be computed in accordance with generally
                 accepted accounting principles applied on a basis consistent
                 with financial statements previously submitted by the Borrower
                 to the Bank.

     (b)  Without the written consent of the Bank, and so long as any
          outstanding remains under the Credit Facility, the Borrower shall 
          not:   

          (i)    Permit the ratio of its current assets to its current
                 liabilities to be less than 1.5:1.0.

          (ii)   Permit its Tangible Net Worth to be less than US$25,000,000 and
                 increasing to US$27,000,000 at 8-31-96; and increasing by 50%
                 of quarterly net income thereafter.

          (iii)  Permit its total liabilities divided by Tangible Net Worth to
                 exceed 2.0:1.0.

          (iv)   Permit the ratio of its earnings before deducting interest
                 expense and taxes to its interest expense to be less than
                 1.5:1.0.

          (v)    Advance any funds and/or dividends in an aggregate amount
                 greater than US$3,000,000 to affiliated companies through July
                 31, 1997.

          (vi)   Create or assume or permit to exist or arise any mortgage,
                 debenture, charge, or any other encumbrance or security
                 whatsoever over any of its assets or property, except for liens
                 in the ordinary course of business and liens for taxes,
                 assessments or other governmental charges which are not
                 delinquent and are part of the ordinary course of business, or
                 which are being contested in good faith and for which adequate
                 reserves have been established in agreement with the Bank.

          (vii)  Allow the legal or beneficial ownership of the Borrower to be
                 changed.

          (viii) Guarantee the liabilities of any other legal entity, affiliated
                 or unaffiliated.


11.  ACCELERATION OF PAYMENT
     -----------------------     
     
     Upon the occurrence of any one of the following events, the Borrower's
     indebtedness to the Bank hereunder shall immediately become due and payable
     without any notice or demand from the Bank:

     (a)  The Borrower or the Guarantors fail to pay (i) any installment of
          interest on any amount payable hereunder within 5 days after the due
          date thereof, or (ii) any installment of principal hereunder when due.

     (b)  The Borrower or the Guarantors fail to observe or perform any other
          term of the Agreement and such failure continues unremedied for a
          period of 15 days after the earlier of (i) the giving of notice to
          Borrower or Guarantors by the Bank of such failure, or (ii) the
          Borrower's or the Guarantors' actual knowledge of such failure; or the
          Borrower or the Guarantors make any materially incorrect or misleading
          representation, warranty, or certificate to the Bank which was
          materially incorrect or misleading when made; or make any materially
          incorrect or misleading representation in any financial statement or
          other information delivered to the Bank; or default under the terms of
          any agreement or instrument relating to any debt for borrowed money
          such that the creditor declares the debt due before its maturity.

     (c)  A default under the Domestic Facility.


                            /s/JAS          /s/AHG
                         ------------    ------------
                            INITIAL         INITIAL
                            (Bank)         (Borrower)


   

<PAGE>
 
                                       5

     (d)  The Borrower or the Guarantors default under the terms of any loan
          agreement, mortgage, security agreement or any other document executed
          in connection with this Agreement and such default continues
          unremedied for a period of fifteen days after the earlier of (i) the
          giving of notice to Borrower or Guarantors by the Bank of such
          failure, or (ii) the Borrower's or the Guarantors' actual knowledge of
          such failure; or if any guaranty of this Credit Facility becomes
          unenforceable in whole or in part, or the Guarantors fail to promptly
          perform under such a guaranty.

     (e)  The Borrower or the Guarantors become insolvent or unable to pay their
          debts as they become due.

     (f)  The Borrower or the Guarantors make an assignment for the benefit of
          creditors; consent to the appointment of a custodian, receiver or
          trustee for it or a substantial part of its assets; or commence any
          proceeding under any bankruptcy, reorganization, liquidation or
          similar laws of any jurisdiction.

     (g)  A custodian, receiver or trustee is appointed for the Borrower or the
          Guarantors or for a substantial part of its assets without the
          consent of the party against which the appointment is made.

     (h)  Proceedings are commenced against the Borrower or the Guarantors under
          any bankruptcy, reorganization, liquidation, or similar laws of any
          jurisdiction and not dismissed within 30 days from the commencement
          thereof, or the Borrower or the Guarantors consent to the commencement
          of such proceedings.

     (i)  Any final judgment for the payment of money in excess of US$500,000 is
          entered against the Borrower or the Guarantors, or any attachment,
          levy or garnishment is issued against any property of the Borrower or
          the Guarantors and the same shall not be discharged or a stay of
          execution thereof shall not be procured, within 30 days from the date
          of entry thereof.

     (j)  The Borrower or the Guarantors, without the Bank's written consent, is
          dissolved, merges or consolidates with any third party; leases, sells
          or otherwise conveys a material part of its assets or business outside
          the ordinary course of business; or agrees to do any of the foregoing.

     (k)  There is a substantial change in the existing or prospective financial
          condition of the Borrower or the Guarantors which the Bank in good
          faith determines to be materially adverse taken as a whole.

12.  PAYMENTS WITHOUT DEDUCTION
     --------------------------

     All payments by the Borrower hereunder shall be made without set-off or
     counterclaim and free and clear of and without deducting or withholding for
     or on account of all present and future taxes, levies, imposts, duties,
     fees or other restrictions or conditions whatsoever.

13.  LIEN AND SET-OFF
     ----------------

     To secure payment of any indebtedness of the Borrower under this Agreement
     and all the Borrower's other liabilities to the Bank, the Borrower grants
     to the Bank a continuing security interest in all securities and other
     property of the Borrower in the custody, possession or control of the Bank
     and all balances of deposit accounts of the Borrower with the Bank. The
     Bank shall have the right upon occurrence of an event described in Section
     11 hereof to apply its own debt or liability to the Borrower, or to any
     other party liable for payment under this Agreement, in whole or partial
     payment of the Borrower's indebtedness or its other present or future
     liabilities to the Bank, without any requirement of mutual maturity.


                            /s/JAS          /s/AHG
                         ------------    ------------
                            INITIAL         INITIAL
                            (Bank)         (Borrower)


<PAGE>
 
                                       6

14.  EXPENSES
     --------

     The Borrower shall pay or procure the payment of all stamp and other duties
     and taxes and all registration and other like fees to which this Agreement
     or other document referred to herein may be subject and shall reimburse the
     Bank on demand for all expenses (including reasonable legal fees,
     translation and other out-of-pocket expenses) incurred by the Bank in
     connection with the negotiation, preparation, execution and enforcement of
     this Agreement.

15.  NOTICE
     ------

     Notice from one party to another relating to this Agreement shall be deemed
     effective if made in writing (including telecommunications) and delivered
     to the recipient's address, telex number or facsimile number set forth
     under its name below by any of the following means: hand delivery,
     registered or certified mail, postage prepaid, with return receipt
     requested, mail, postage prepaid, overnight courier service or facsimile,
     telex or other wire transmission with request for assurance of receipt in a
     manner typical with respect to communication of that type. Notice made in
     accordance with this section shall be deemed delivered upon receipt if
     delivered by hand or wire transmission, three business days in the place of
     receipt after mailing if mailed by registered or certified mail or one
     business day in the place of receipt after mailing or deposit with an
     overnight courier service if delivered by express mail or overnight
     courier.

16.  WAIVER
     ------

     No delay on the part of the Bank in the exercise of any right or remedy
     shall operate as a waiver. No single or partial exercise by the Bank of any
     right or remedy shall preclude any other future exercise of it or the
     exercise of any other right or remedy. No waiver or indulgence by the Bank
     of any default shall be effective unless in writing and signed by the Bank,
     nor shall a waiver on one occasion be construed as a bar to or waiver of
     that right on any future occasion.

17.  GOVERNING LAW
     -------------

     This agreement shall be governed by and construed in all respects in
     accordance with the laws of Hong Kong and the Borrower hereby irrevocable
     submits to the non-exclusive jurisdiction of the Hong Kong courts. This
     Agreement is binding on the Borrower and its successors, and shall inure to
     the benefit of the Bank, its successors and assigns.

18.  MISCELLANEOUS
     -------------

     (a)  This agreement and any related loan documents embody the entire
          agreement and understanding between the Borrower and the Bank and
          supersede all prior agreements and understandings relating to their
          subject matter. If any one or more of the obligations of the Borrower
          under this agreement or the Note shall be invalid, illegal or
          unenforceable in any jurisdiction, the validity, legality and
          enforceability of the remaining obligations of the Borrower shall not
          in any way be affected or impaired, and such validity, illegality or
          unenforceability in one jurisdiction shall not affect the validity,
          legality or enforceability of the obligations of the Borrower under
          this Agreement or the Note in any other jurisdiction.

                            /s/JAS          /s/AHG
                         ------------    ------------
                            INITIAL         INITIAL
                            (Bank)         (Borrower)
     
<PAGE>
                                      7
 
(b)  Section headings are for convenience of reference only and shall not affect
     the interpretation of this Agreement.

Executed by the parties on July 31, 1996.


For and on behalf of                     For and on behalf of
First National Bank of Chicago           CellStar (Asia) Corporation Limited
Hong Kong Branch




/s/   James A. Schmelter                 /s/   Alan H. Goldfield
-----------------------------------      ---------------------------------------
Name: James A. Schmelter                 Name: Alan H. Goldfield


Address for Notices:                     Address for Notices:

13/F Jardine House                       Rooms 509-510,5/F, Block B
-----------------------------------      ---------------------------------------
1 Connaught Place, Central               Sing Tao Building
-----------------------------------      ---------------------------------------
Hong Kong                                1 Wang Kwong Road, Kowloon Bay
-----------------------------------      ---------------------------------------
                                         Kowloon, Hong Kong
-----------------------------------      ---------------------------------------


Telephone No: (852) 2844-9222            Telephone No: (852) 2757-0998
              ---------------------                    -------------------------
Facsimile No: (852) 2844-9318            Facsimile No: (852) 2759-5255
              ---------------------                    -------------------------
Telex No    : 83536 FCHOP HX             Telex No    :         /
              ---------------------                    -------------------------