Retailer’s Ordering and Discounting Policies Under Advance Sales Discount and Trade Credit Based on Sharia

The use of conventional model to minimize the inventory cost creates a disturbance between the sellers and buyers. It creates a usury since the payment conducts to interest paid and interest earned. In this paper, sharia principle is implemented, that is Bai Al Istishna which allows credit period and margin agreement as the payment. The model is engaged to replenishment cycle time and price discount policy to attract the customer’s demand which based on sharia principle. This paper provides a useful mathematical model based on sharia principles in order to usury/interest can be eliminated in the trading process.