Institutional investors usually employ mean-variance analysis to determine optimal portfolio weights. Almost immediately upon implementation, however, the portfolio's weights become sub-optimal as changes in asset prices cause the portfolio to drift away from the optimal targets. In an idealized...

That investors should diversify their portfolios is a core principle of modern finance. Yet there are some periods where diversification is undesirable. When the portfolio’s main growth engine performs well, investors prefer the opposite of diversification. An ideal complement to the growth...

Policy portfolios are a fixture of institutional investment management, but they may not serve the purposes for which they are intended. A policy portfolio serves primarily as an expression of an investor's return and risk preferences. Secondarily, it serves as a benchmark for determining the...

Financial analysts typically estimate volatilities and correlations from monthly or higher frequency returns when determining the optimal composition of a portfolio. Although it is widely acknowledged that these measures are not necessarily stationary across samples, most analysts assume...

We use a proprietary database of private equity returns to measure the excess return of private equity over public equity and to partition it into two components: an asset class alpha and compensation for illiquidity. Our evidence suggests that private equity managers, as a group, generate alpha...

The authors describe a new statistical concept called relevance from a conceptual and mathematical perspective, and based on their mathematical framework, they present a unified theory of relevance, regressions, and event studies. They also include numerical examples of how relevance is used to...

Investors take for granted that returns are recorded in units of time, such as days, months, or years. Yet some time periods include unusual events that reasonably cause asset prices to change, whereas other periods are relatively free of unusual events, in which case returns mostly reflect...

Financial analysts assume that the reliability of predictions derived from regression analysis improves with sample size. This is generally true because larger samples tend to produce less noisy results than smaller samples. But this is not always the case. Some observations are more relevant...

The authors introduce a new index of the business cycle that uses the Mahalanobis distance to measure the statistical similarity of current economic conditions to past episodes of recession and robust growth. Their index has several important features that distinguish it from the Conference...

Investors rely on the stock-bond correlation for a variety of tasks, such as forming optimal portfolios, designing hedging strategies, and assessing risk. Most investors estimate the stock-bond correlation simply by extrapolating the historical correlation of monthly returns and assume that this...