We implement a dynamic programming algorithm on a computational grid consisting of loosely coupled processors, possibly including clusters and individual workstations. The grid changes dynamically during the computation, as processors enter and leave the pool of workstations. The algorithm is...

We apply numerical dynamic programming to multi-asset dynamic portfolio optimization problems with proportional transaction costs. Examples include problems with one safe asset plus two to six risky stocks, and seven to 360 trading periods in a finite horizon problem. These examples show that it...

Because of differences in accrued gains and investors' tax-sensitivity, capital gains "lock-in" varies across mutual funds even for the same stock at the same time. Using this variation, we show that tax lock-in affects funds' governance decisions. Higher tax lock-in decreases the likelihood a...

This paper brings new evidence from the privatized social security system in Mexico, offering insight into investment behavior and the efficacy of government "nudges" in the context of profit maximizing firms. We use administrative data from the social security system surrounding the government...

Borrowing decisions affect most households, with large stakes and implications for subfields as varied as macroeconomics and industrial organization. I review theoretical and empirical work on household debt: its prevalence, level, growth, and composition, as well as various measures of consumer...

Berkshire Hathaway has realized a Sharpe ratio of 0.76, higher than any other stock or mutual fund with a history of more than 30 years, and Berkshire has a significant alpha to traditional risk factors. However, we find that the alpha becomes insignificant when controlling for exposures to...

Standard Fama-French and Carhart models produce economically and statistically significant nonzero alphas, even for passive benchmark indices such as the S&P 500 and Russell 2000. We find that these alphas arise primarily from the disproportionate weight the Fama-French factors place on small...

We investigate optimal consumption, asset accumulation and portfolio decisions in a realistically calibrated life-cycle model with flexible labor supply. Our framework allows for wage rate uncertainly, variable labor supply, social security benefits and portfolio choice over safe bonds and risky...

We provide new empirical evidence suggesting that the marginal investor in mutual funds behaves differently across market conditions. If the marginal investor allocates capital across mutual funds rationally, then the relative performance of funds should be unpredictable. We find however that...

The recent growth in the market for target-date funds (TDFs) allows us to study how mutual fund families structure new investment products. Given the widespread, legislation-induced use of TDFs as default investments in defined contribution retirement plans, this market holds special policy...