This paper examines the optimal consumption and portfolio-choice problem of long-horizon investors who have access to a riskless asset with constant return and a risky asset (“stocks”) with constant expected return and time-varying precision—the reciprocal of volatility. Markets are incomplete, and investors have recursive preferences defined over intermediate consumption. The paper obtains a solution to this problem which is exact for investors with unit elasticity of intertemporal substitution of consumption and approximate otherwise. The optimal portfolio demand for stocks includes an intertemporal hedging component that is negative when investors have coefficients of relative risk aversion larger than one, and the instantaneous correlation between volatility and stock returns is negative, as typically estimated from stock return data. Our estimates of the joint process for stock returns and precision (or volatility) using U.S. data confirm this finding. But we also find that stock return volatility does not appear to be variable and persistent enough to generate large intertemporal hedging demands.

Over the period 1975 to 2005, the U.S. dollar (particularly in relation to the Canadian dollar), the euro, and the Swiss franc (particularly in the second half of the period) moved against world equity markets. Thus, these currencies should be attractive to risk‐minimizing global equity investors despite their low average returns. The risk‐minimizing currency strategy for a global bond investor is close to a full currency hedge, with a modest long position in the U.S. dollar. There is little evidence that risk‐minimizing investors should adjust their currency positions in response to movements in interest differentials.

Optimal Life-Cycle Investing with Flexible Labor Supply: A Welfare Analysis of Life-Cycle Funds by Francisco J. Gomes, Laurence J. Kotlikoff and Luis M. Viceira. Published in volume 98, issue 2, pages 297-303 of American Economic Review, May 2008