Michael S. Farber (Davis Polk & Wardwell, New York) has published Equity, Debt, NOT –- The Tax Treatment of Non-Debt Open Transactions, 60 Tax Law. 635 (2007). Here is part of the Introduction:

Part I of this Article describes various instruments being issued in the capital markets today, including prepaid forwards, reverse and mandatory exchangeables, and credit linked notes. Part II briefly surveys the law relating to the traditional debt-equity dichotomy and also reviews some of the authorities touching, to varying degrees, on the characterization and taxation of NOTs. Part III discusses the appropriate treatment of our putative NOTs, both under current law and as a normative matter. Part IV offers several conclusions.