Tobias’s research is focused on discretionary trusts. His current research proposes that the development of discretionary trusts has produced a new institution founded on a legal relationship that is distinct from traditional fixed trusts. Fixed trusts are characterised by distributive entitlements analogous to property, whereas discretionary trusts are characterised by procedural entitlements governing the trustees’ exercise of discretion. This argument has important ramifications for how different trusts ought to be controlled and regulated by the courts. It also explains why discretionary trusts have a unique impact on areas of legal doctrine that operate on conceptions of ownership, such as tax, family and bankruptcy law. Assets held in discretionary trusts are not beneficially owned, in the sense that no individuals are entitled to benefit from those assets as of right. Tobias is contributing to the development of our understanding of trust law by applying the insights of this distinction to both well-traversed and overlooked topics in trust law including Quistclose trusts, mere and trust powers, and the regulation of decision-making. A further interest of Tobias’s is investigating how trusts are understood and utilised by lay and professional people.