Thin capitalization rules limit firms’ ability to deduct internal interest payments from taxable income, thereby restricting debt shifting activities of multinational firms. Since multinational firms can limit their tax liability in several ways, regulation of debt shifting may have an impact on other profit shifting methods. We therefore provide a model in which a multinational firm can shift profits out of a host country by issuing internal debt from an entity located in a tax haven and by manipulating transfer prices on internal goods and services. The focus of this paper is the analysis of regulatory incentives, \((i)\) if a multinational firm treats debt shifting and transfer pricing as substitutes or \((ii)\) if the methods are not directly connected. The results provide a new aspect for why hybrid thin capitalization rules are used. Our discussion in this paper explains why hybrid rules can result in improvements in welfare if multinational firms treat methods of profit shifting as substitutes.

资本弱化规则限制了公司从应税收入中扣除内部利息支付的能力，从而限制了跨国公司的债务转移活动。由于跨国公司可以通过多种方式限制其纳税义务，因此对债务转移的监管可能会对其他利润转移方法产生影响。因此，我们提供了一个模型，在该模型中，跨国公司可以通过向位于避税港的实体发行内部债务并通过操纵内部商品和服务的转移价格将利润转移到东道国之外。本文的重点是分析监管激励，\((i)\)如果跨国公司将债务转移和转让定价视为替代品或\((ii)\)如果方法没有直接连接。结果提供了为什么使用混合资本弱化规则的新方面。我们在本文中的讨论解释了如果跨国公司将利润转移方法视为替代品，为什么混合规则会导致福利的改善。