For what reasons does an obligation to surrender the contractual surrogate arise under §§ 285(1), 816(1), 818(1) and (2), and 822 of the German Civil Code (BGB)? Nathan Krian explores this question by examining the functional equivalents in the law of England and Wales. The insights gained from this analysis are then compared with the reasoning developed in German law in similar contexts, in order to make the value judgments of English law useful for the German legal discourse. Particularly revealing is the allocation function of contractual promises in English law, which is of special interest for explaining the obligation to surrender the contractual surrogate under § 285(1) BGB. In this context, Krian analyzes cases in which the allocation function of contractual promises is realized through tracing-especially in the context of the Vendor Purchaser Constructive Trust. To this end, the study first provides an overview of the trust as a legal institution and of the requirements of the Vendor Purchaser Constructive Trust and specific performance. Finally, the examination of the surrender of contractual surrogates in English law also includes a discussion of the concepts of disgorgement and damages, in order to present a comprehensive picture of the mechanisms giving rise to such claims.