With over $1 trillion in assets, the U.S. Social Security trust fund is the largest pension reserve in the world, and potentially a model for other developed countries facing future financing problems. But are those assets actually worth anything?' This question has generated a heated debate in...

This paper proves that the stock-bond portfolio choice of the Social Security trust fund is equivalent in general equilibrium to the tax treatment of capital income by the non-social security part of government. A larger [smaller] share of social security's portfolio invested in stocks is...