The article inquires whether segmentation concepts might shed a new light on the debates about the generalization of employment risks in Germany and develops the concept of firm employment sub-systems. The result of our empirical analyses is that the German labour market structure is shifting from a hegemony of Internal Labour Markets to a tense and instable co-existence of Internal and External markets, with East Germany having taken the lead. There is neither a generalisation of risks nor a stable division of employment. We rather observe dynamic segmentation with shifts between Internal and External Markets and endogenous transformations within segments.