EXHIBIT 10.4
                                          
                       BMC STOCK OPTION EXERCISE LOAN PROGRAM
                                          
                                          


PURPOSE:

     
     -    To facilitate stock option holder's exercise of stock options.

     -    To encourage share ownership by key employees.

     -    To minimize tax consequences to employees on stock option exercises by
          providing the means to carry BMC stock for a sufficient period to
          qualify for long-term capital gains treatment.

     -    To minimize the need to sell shares in the open market to pay for
          taxes due upon exercise of options.


ELIGIBILITY:

     -    Effective date of the Program is April 22, 1993.

     -    Any employee of BMC with exercisable non-qualified stock option grants
          is eligible to participate in the Program.

     -    Approval of loans is at the sole and absolute discretion of the
          Compensation Committee or its designee.

     -    Employees holding options which are exercisable and vested at the time
          a loan is requested (whether or not exercisable and vested at the
          effective date of the Program) are eligible to be considered by the
          Compensation Committee for loan approval.


AMOUNT OF LOANS:

     -    The total amount which any employee may borrow under the Program shall
          be determined by the Compensation Committee in its sole and absolute
          discretion.

          -    In addition, any employee's first loan request may not exceed
               100% of the exercise price of the option to be financed with such
               loan, plus 100% of the state and federal income taxes actually
               paid within 15 months of such exercise on any income recognized
               by reason of such exercise.

          -    Any loan request by an employee under the Program subsequent to
               the employee's first loan request may not exceed the lesser of
               (a) 100% of the exercise price of the option to be financed with
               such loan, plus 100% of the state and federal income taxes
               actually paid within 15 months of such exercise on any income
               recognized by reason of such exercise or (b) such amount that
               when added to the principal amount of all then outstanding loans
               under the Program will not exceed 60% of the market value of all
               the BMC stock of such employee pledged as collateral immediately
               following such loan under the Program (determined as provided
               below under "Loan Terms") (including any stock pledged upon the
               option exercise requested to be financed by such subsequent loan)
               or (c) eight times the employee's then-current base annual
               salary.

          -    The amount of any loan used for the payment of taxes shall be
               advanced only as and when payment of such taxes is made by the
               employee.

          -    In no event shall any advance under the Program be made which
               would cause the aggregate amount of principal and accrued
               interest outstanding under all loans to any employee to exceed
               100% of the market value of all BMC stock of such employee
               pledged as collateral under the Program at the time of such
               advance.

          -    In no event shall the total outstanding balance of an employee's
               loans, including principal and accrued interest, exceed 100% of
               the market value of all BMC stock pledged as collateral for such
               employee's loans under the Program.


LOAN TERMS:

     -    Loans to any employee under the Program shall be interest free (a)
          with respect to all amounts advanced to pay any option exercise price,
          and (b) with respect to amounts advanced to pay income taxes to the
          extent the aggregate principal amount of such tax payment advances
          outstanding under the Program to the employee is not greater than the
          product of the amount of the employee's base annual compensation plus
          target bonus amount under the Management Incentive Plan as of the
          first day of the then current calendar quarter multiplied times two
          (such product the "Interest Free Loan Amount").

     -    To the extent the aggregate outstanding principal amount of tax
          payment advances to any employee is in excess of the Interest Free
          Loan Amount at any time, the amount of such excess shall bear interest
          at the following rates:

          (a)  The interest rate applicable under any short-term borrowings by 
               BMC if any such borrowings are outstanding at the beginning of 
               any calendar quarter, such rate to apply for the entire calendar
               quarter.

          (b)  The interest rate payable to BMC under its short-term money 
               market investments if BMC has no short-term borrowings 
               outstanding at the beginning of any calendar quarter, such rate 
               to apply for the entire calendar quarter.

     -    Any interest shall accrue as provided above, but shall not be payable
          except as provided below, and shall not compound whether or not paid
          from year-to-year or otherwise.

     -    Notes will be in the form of a Demand Promissory Note.

     -    The BMC stock will be held as collateral for all loans under the 
          Program and "legended" to the Company.

     -    The "market value" of BMC stock as of any date shall be determined by
          reference to the closing price of BMC stock on the NYSE on the 
          business day preceding such determination.


METHODS OF REPAYMENT:

     -    30% of any payout under the Management Incentive Plan (net of 
          estimated applicable state and federal income taxes and other 
          withholding) received while a loan is outstanding will be 
          applied to repayment of the loan.

     -    Required Paydowns from Stock Sale Proceeds - A portion of proceeds 
          from the sale of BMC stock pledged under the Program would be 
          required to be applied to the repayment of amounts outstanding 
          under all loans under the Program in an amount equal to the 
          lesser of (a) 100% of such proceeds or (b) (i) the amount of all 
          accrued interest, plus (ii) the product of the amount of such 
          proceeds remaining after payment of all accrued interest multiplied 
          times a fraction the numerator of which is the principal amount of 
          the loan and the denominator of which is the market value of the BMC 
          stock pledged as collateral for such loan immediately following such 
          payment (stock will be legended but legend will be released upon 
          receipt of proceeds).

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     -    Any dividends received by an employee in respect of BMC stock pledged
          for a loan under the Program, net of deduction for applicable 
          estimated state and federal income taxes and other withholdings on 
          such dividends, shall be applied to repayment of the loan.

     -    Repayment can be effected by other means at the employee's option,
          including through payroll deduction, use of the employee's flex 
          account, or bonus proceeds beyond the 30% described above.

     -    All payments shall be applied first to accrued interest, next to any
          amount of principal advanced to pay income taxes and then to all other
          principal.

     -    Partial Release of Pledged Stock upon Payment (whether or not with 
          stock sale proceeds) - If the market value of BMC stock pledged as 
          collateral for loans under the Program to any employee (excluding 
          the market value of any shares sold to yield payment proceeds) 
          exceeds the amount of the loans prior to payment on a loan, such 
          stock shall be released upon any payment of all then accrued 
          interest and any amount of principal, upon request of the employee, 
          such that ratio of the principal amount of the loan outstanding 
          immediately after such payment to the market value of the shares 
          remaining pledged immediately after such release is not greater than 
          the ratio of the principal amount of the loan outstanding immediately 
          prior to such payment to the market value of the shares immediately 
          prior to such release (excluding the market value of any shares sold 
          to yield payment proceeds).  No such release shall be required unless 
          at least 100 shares of pledged BMC stock is eligible for release.

     -    Required Paydown Due to Drop in Stock Value - If the market value of 
          BMC stock pledged by an employee as collateral for loans under the 
          Program falls below 100% of the employee's total outstanding balance 
          for all loans under the Program, including principal and accrued 
          interest, the employee shall be required, within five (5) business 
          days notice of demand by the Compensation Committee, to either 
          (i) contribute additional shares of BMC stock as collateral in an 
          amount sufficient to raise the market value of BMC stock held as 
          collateral in excess of the total outstanding balance or (ii) pay to 
          BMC the difference in cash between the total outstanding balance and 
          the market value of all BMC stock pledged as collateral for the 
          employee's loans.
     

EVENTS TRIGGERING DEMAND FOR PAYMENT:

     -    Termination of employment from BMC would require repayment of 
          principal within 45 days or such longer period determined at the 
          discretion of the Compensation Committee.

     -    In the event of the death or long-term disability of the employee,
          repayment may be extended up to six months or longer at the discretion
          of the Compensation Committee.

     -    Employee's declaration of bankruptcy would require immediate repayment
          of principal.

     -    Drop in market value of BMC stock held as collateral below 100% of an
          employee's total outstanding loan balance, including principal and
          accrued interest, under the Program.

     -    Notwithstanding these events, demand for repayment may be made at any
          time by the Compensation Committee.


EVENTS PERMITTING EXTENSION OF REPAYMENT:

     -    Written consent of the Compensation Committee, at its sole and 
          absolute discretion.

     -    Where it is determined by the Compensation Committee in its sole and
          absolute discretion that repayment would result in adverse 
          consequences to the Company or employee.  For example:

          -    Sale of BMC stock to enable repayment would cause personal
               liability under Section 16(b) of the Exchange Act.

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          -    Sale of BMC stock at current prices, or in large blocks may
               abnormally suppress market price of the stock or cause similar
               hardship.


CONSEQUENCES TO EMPLOYEE:

     -    For tax purposes, the employee must recognize income in an amount 
          equal to the interest-free discount received on the loan proceeds.  
          On a "demand" note, this amount is calculated each December on the 
          principal amount of the loan using the "applicable federal rate" 
          (AFD).

     -    Imputed interest will not be subject to federal or state income tax
          withholding but WILL be subject to FICA and/or Medicare tax 
          withholding prescribed by the tax regulations.

     -    Employee SHOULD be entitled to an offsetting interest deduction in the
          current year if the employee has sufficient net investment income, or 
          in the year the stock is sold as an offset to the gain on the stock.

     -    Employees should, however, consult with their own tax advisers to
          determine the actual tax consequences of participation in the Program.


REQUIRED DISCLOSURES:

     -    Schedule II of Form 10-K requires the disclosure of aggregate
          indebtedness of more than $100,000 from any employee.  Disclosure
          includes name, amount of indebtedness, due date, interest rate, 
          terms of repayment and collateral.

     -    The Annual Report requires disclosure of the sum total of all amounts
          due from officers and directors, even though the dollar amount may be
          relatively small.

     -    Proxy disclosure of the loan amount and the compensation element is
          required.  Filings necessary to comply with margin stock rules will be
          made.
                                         
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