In 2018, the European Union (EU) introduced a new mandatory reporting requirement for a wide range of cross‐border tax arrangements (EU Directive 2018/822, also known as DAC6). Unlike prior corporate transparency initiatives, which put the reporting responsibility primarily on the taxpayers, this directive puts the initial reporting responsibility on the third‐party intermediaries who are involved in the reportable arrangement at any stage during the planning and execution process. We exploit the adoption of DAC6 in the EU to examine the effectiveness of third‐party reporting in curbing cross‐border tax planning by multinationals. Using a difference‐in‐differences research design, we find that affected firms reduce income shifting and report higher effective tax rates in the post‐adoption period. The reduction in income shifting is stronger for affiliates operating in countries without legal professional privilege extensions and in countries where noncompliance penalties are higher. Our results highlight the importance of strong third‐party reporting requirements in constraining cross‐border tax planning.

In this study, we examine the effect of increased tax transparency on the tax planning behavior of European banks. In 2014, the European Union introduced public country‐by‐country reporting requirements to the banking industry. Treating this new requirement as an exogenous shock, we find limited evidence consistent with a decline in income shifting by the banks' financial affiliates in the post‐adoption period (starting from 2015). We do not, however, find robust evidence of a significant change in the consolidated book effective tax rates among the affected banks. Our findings suggest that increased transparency from public country‐by‐country reporting can deter tax‐motivated income shifting but that it did not appear to materially influence the banks' overall tax avoidance. Our findings have policy implications for the ongoing debate between the European Parliament, the Organisation for Economic Co‐operation and Development, and accounting standard‐setting bodies on whether to require multinationals to publish country‐by‐country reports.