Journal article: Discrimination models have difficulties to reproduce a persistent discrimination without assuming that prejudiced firms are more productive and results lead to workers' segregation. The model uses oligopsony and heterogeneity of workers' preferences to obtain a persistent discrimination. Firms hire both types of workers and pay a lower wage to the workers discriminated against. Consequently, the existence of discrimination allows a nonzero profit for unprejudiced firms and they have also no incentives to push out prejudiced firms.