HM Treasury’s latest consultation on the UK’s new interest deductibility regime sets out further detail on the design and implementation of the rules. It is clear that the UK remains committed to implementing the OECD’s recommendations by the challenging deadline of 1 April 2017. However, the proposals in the document suggest a greater level of complexity than anticipated, with the introduction of a raft of new definitions and concepts. The challenge for UK business is to assess the impact of these new rules, without also having clarity on how other tax jurisdictions will implement the OECD’s recommendations.