Islamic finance is a financial concept based on Islamic sharia. The underlying principle of Islamic finance is the prohibition of usury, gharar and masyir. In addition to these principles, the concept of Islamic finance which is built on the basis of justice makes many people tend to choose Islamic finance rather than conventional. In this article, we will discuss the Sharia investment model with a profit-loss sharing scheme as an alternative model to replace the practice of lending money at high interest by moneylenders in traditional markets (Rentenir scheme). Both models are applied in a lending transaction between traders and investors with a share of the results in the profit-loss sharing model of 5% and interest on loan repayments for the loan sharks of 20%. Furthermore, from each model the acquisition value is calculated in the form of the optimal portion / profit ratio for each trader and investor. The results obtained indicate that the earnings obtained by traders for the Sharia model are greater than those from the Rentenir model. Furthermore, the acquisition value of investors for the Sharia model is minus and the acquisition value of investors from the Rentenir model is 25.56%. The acquisition value of investors from the Rentenir model is very high, while in the Sharia model, investors experience losses. From these two parameters it can be concluded that the Sharia model with a profit sharing scheme is a model that benefits small traders, while the Rentenir model is a model that needs to be avoided because it is detrimental to traders and also uses the concept of usury which is forbidden in Islam.