This paper develops a simple theory of the supply of index bonds by a firm, and uses that model to examine in some detail possible reasons for the non-existence of privately issued index bonds in the United States. The major elements of the theory involve the trade-off between the tax advantages of using debt finance and the increasing risk of bankruptcy debt finance involves. The theory is first used to examine the supply of nominal bonds -- it is thus a theory of the debt-equity ratio. Then the firm's optimal supply of index bonds is examined, and the values of the firm using the alternative debt instruments is compared. In general, there is no reason to think that nominal bonds dominate index bonds -- i.e. the theory cannot explain why firms have not issued index bonds. The paper then turns to a number of other reasons that have been advanced for the non-issue of indexed bonds in the United States, such as the tax treatment of such instruments and the argument that their issue would saddle the firm with open-ended obligations