Starting from discussions on the validity of the classical assimilation concept, a general model for the explanation of different structural outcomes of interethnic relations is developed. The core of the model builds on the assumption that different outcomes are the often unintended and situation-logic results of (mis-)investments in and with ethnic and non-ethnic capital. Central initial conditions of the model are group size, social and cultural distances and the availability of social capital. The model specifies the mutual relations between these three constructs. Different variants of intergenerational integration of immigrants can thus be reconstructed as special cases of a general mechanism.