Debt Shifting and Thin-Capitalization Rules – German Experience and Alternative Approaches

This paper presents the general design of thin-capitalization rules and summarizes the economic effects of such rules as identified in theoretical models. We review empirical studies providing evidence on the experience with (German) thin-capitalization rules as well as on the adjustment of German multinationals to foreign thin-capitalization rules. Special emphasis is given to the development in Germany, because Germany went a long way in limiting interest deductibility by enacting a drastic change in its thin-capitalization rules in 2008, and because superb German data on multinational finance allows for testing several aspects consistently. We then discuss the experience of the Nordic countries with thin-capitalization rules. Briefly reviewing potential alternatives as well, we believe that the arm’s-length principle is administratively too costly and impracticable, whereas we argue that controlled-foreign-company rules might be another promising avenue for limiting internal debt shifting. Fundamental tax reforms towards a system with either "allowance for corporate equity" (ACE) or a "comprehensive business income tax" (CBIT) should also eliminate any thin-capitalization incentive.