This chapter brings us to the heart of finance: the Wall Street investment banks. It discusses the structured securities through which they parcelled up and re-sold the loan repayment commitments of mostly poorer residential property buyers in the United States, leading to the crash of 2007–2009 and the global financial crisis that followed. The objective is not to create new interpretations of the crisis itself, but rather to show the implications for the larger argument of the book. The chapter asks how these new financial products were developed, how they were fitted to the existing institutional and discursive environment, and what work was done to manipulate that environment to fit them. It also asks how these products were constructed as having value, and how financial actors were brought into the asset circles for them, stressing the central role played by the ratings agencies in constructing asset sets: groups of assets that investors come to think of as equivalent to each other, so that investors who are part of the asset circle for existing assets in the set are smoothly inducted into the asset circle for further assets simply by inserting these new assets into the set.