This paper studies portfolio optimization through improvements of ex-ante conditional covariance estimates. We use the cross-section of stock returns over a 52-year sample to analyze trading performance by implementing the machine learning algorithm of hierarchical clustering. We find that...

In investment, particularly in the portfolio management, the risk and returns are two crucial measures in making investment decisions. This paper attempts to provide a brief theoretical explanation with examples on determining the returns and associated risk of shares, and of the portfolio of...

In the U.S., the geometric return on stocks has been higher than the geometric return on bonds over long periods. We study whether balanced portfolios have a larger geometric return (and expected log return) than stock portfolios when the risk premium is low. We use a theoretical model and...

I characterize the global solution to the portfolio problem of two heterogeneous investors with general preferences, in a two-tree, two-good environment. Investors have recursive preferences and a bias in consumption towards a preferred good. The framework highlights the role of the allocation...

We show that firms' idiosyncratic volatility obeys a strong factor structure and that shocks to the common factor in idiosyncratic volatility (CIV) are priced. Stocks in the lowest CIV-beta quintile earn average returns 5.4% per year higher than those in the highest quintile. The CIV factor...

We examine asset prices in a representative-agent model of general equilibrium. Assuming only that individuals are risk averse, we determine conditions on the changes in asset risk that are both necessary and sufficient for the asset price to fall. We show that these conditions neither imply,...

A dynamic model featuring a stochastic technology frontier shows significant impact of technology adoption for asset prices. In equilibrium, firms operating with old capital are riskier because costly technology adoption restricts their flexibilities in upgrading to the latest technology, making...

Empirical measures of world consumption growth risk have failed to rationalize the cross-section of country equity returns. We propose a new factor, termed "the global consumption factor", to explain the patterns in risk premiums on international equity markets. We identify this factor as the...