AbstractThis paper contributes to the discussion on borrowing size effects. According to this concept, smaller cities that are part of larger functional urban regions can utilise metropolitan functions and economic externalities, thereby boosting their regional performance. This is conceptualised in the four‐dimension scheme of Meijers and Burger. Consequently, this paper analytically explores and operationalises the borrowed size concept and reveals insights into the relation and spatial distribution of four types of effects: borrowed size, borrowed performance, borrowed function and agglomeration shadow. Research on these spatial effects is applied on a small‐scale spatial level and integrates all municipalities in German urban regions. We find different geographies of effects among the four‐dimensions of borrowed size. City size and centrality degree show a significant influence on positioning in the four borrowed size effect types.