"By employing leverage to gain more exposure to stocks when young, individuals can achieve better diversification across time. Using stock data going back to 1871, we show that buying stock on margin when young combined with more conservative investments when older stochastically dominates...

This paper is no longer available on-line from the NBER. A revised version of the paper has been published as "Diversification Across Time" in the Journal of Portfolio Management 39 (Winter 2013), pp.73-86