One of the most significant forms of trusts that are used in banking transactions are Quistclose trusts, which can provide a lender of money with a proprietary interest in the loan moneys in the event that the borrower goes into insolvency. This chapter considers the overlap between the principles of equity and other commercial uses of trusts structures. A Quistclose trust enables the lender in a loan contract to retain an equitable proprietary interest in the loan money, which provides protection, inter alia, in the event that the borrower were to go into insolvency. There is a growing trend in a number of jurisdictions towards the explanation of commercial trusts as being, in truth, a species of contract. For commercial people it is reassuring to think of trusts as being an extension of the contractual principles that are familiar to them.