0000000000485361
AUTHOR
Kenneth L. Judd
Equilibrium open interest
Abstract This paper analyses what determines an individual investor's risk-sharing demand for options and, aggregating across investors, what the equilibrium demand for options. We find that agents trade options to achieve their desired skewness; specifically, we find that portfolio holdings boil down to a three-fund separation theorem that includes a so-called skewness portfolio that agents like to attain. Our analysis indicates also, however, that the common risk-sharing setup used for option demand and pricing is incompatible with a stylized fact about open interest across strikes.
A Partial Equilibrium Model of Option Markets
This paper addresses the questions who is buying and who is selling options on a stock, the optimal position to hold, and how this affects the price. The individual demand functions and the equilibrium allocation are derived using an asymptotically valid expansion. Trading occurs only at discrete dates; the option does not have to complete the market. The paper also discusses the conditions under which trade results, the importance of heterogeneity for trade, when preferences become irrelevant to price options, and the case in which there is only a spanning demand, but no risk-sharing demand in options.