This chapter examines the law governing the availability of claims to traceable proceeds. It argues that the language used in the case law—which uses the terminology of property rights and of fiduciary relationships—cannot fully explain the law, since such claims are often available in the absence of fiduciary duties and are not available to holders of many types of property right. It argues that such claims instead presuppose a relationship of ‘control of assets’: where the defendant has a legal power to deal with some asset, correlating to a vulnerability to a loss of rights in that asset on the part of the claimant, and coupled with a duty not to exercise the power. It argues that relationships that have this formal structure also share normative characteristics that justify the subordination of defendant autonomy that has been shown to be at the heart of the tracing concept.