Abstract: Consumer credit products have prevailed for a long time, allowing customers to spend first and pay later, stimulating customers to purchase products. Banks, financial services companies, e-commerce platforms have all strategically laid out this industry and provided corresponding online consumer credit services. To make it work out more, companies will offer interest-free consumer credit services. We consider a firm that sells multiple substitutable products and provides interest-free consumer credit services and bears the services costs. We develop a MNL model and incorporate consumer responses to consumer credit services into the model, the firm’s objective is to make the optimal decisions of grace period for each product to maximize the total profit under linear and nonlinear credit service cost structures, respectively. The findings indicate that we can essentially transform the multiple products optimization problem into a single-variable root searching problem, which reduces the calculation complexity; The optimal grace period does not necessarily shrink with the increase of credit service cost and vice versa; Numerical analysis reveals that products with larger profit margins have longer optimal grace periods. We also compare the pros and cons of the two different credit options—uniform optimal grace periods for all products (Option 1) and “one exclusive optimal grace period for one product” (Option 2), we find that firm’s total profit from implementing Option 2 is always larger than that from implementing Option 1, especially when the firm’s ability to utilize the sales revenue is not strong, the profit improvement under Option 2 scheme is more significant.

Key words: consumer credit, grace period, MNL, multiple product optimization