Larry Zelenak (Duke) presents  The Sometimes-Taxation of the Returns to Risk-Bearing Under a Progressive Income Tax today at Northwestern as part of its Tax Policy Colloquium.  Here is part of the opening: 

This paper examines the theoretical and practical arguments against the taxation of risk premium. It considers whether risk premium should be taxed in an ideal world, whether it can be taxed in a non-arbitrary manner by an administrable income tax, and whether it could and should be taxed by some regime separate from the income tax. The paper reaches no definitive policy conclusions; its goal is not so much to dispel confusion as to engender confusion on a higher level and about more important things.