Stephen A. Ross had an uncanny talent for translating economic theory into intuitive and rigorous concepts that were useful to researchers and practitioners alike. His most famous accomplishment, the arbitrage pricing theory, has inspired the ongoing search for factors that explain security...

Smart beta strategies promise to deliver market-beating returns with simplicity and low cost, but the reality is more complicated. Contrary to popular perception, smart beta strategies are neither passive nor well diversified. Nor can they be expected to perform consistently in all market...

Leverage entails a unique set of risks, such as margin calls, which can force investors to liquidate securities at adverse prices. Modern Portfolio Theory (MPT) fails to account for these unique risks. Investors often use portfolio optimization with a leverage constraint to mitigate the risks of...

More than three decades ago, Jacobs and Levy introduced in the Financial Analysts Journal the idea of disentangling returns across numerous factors via cross-sectional analysis, and examined the benefits of using the time-series of returns to disentangled factors for return forecasting. The...

Smart beta strategies promise to deliver market-beating returns with simplicity and low cost, but the reality is more complicated. Contrary to popular perception, smart beta strategies are neither passive nor well diversified. Nor can they be expected to perform consistently in all market...

Leverage entails a unique set of risks, such as margin calls, which can force investors to liquidate securities at adverse prices. Modern Portfolio Theory (MPT) fails to account for these unique risks. Investors often use portfolio optimization with a leverage constraint to mitigate the risks of...

This paper presents fast algorithms for calculating mean-variance efficient frontiers when the investor can sell securities short as well as buy long, and when a factor and/or scenario model of covariance is assumed. Currently, fast algorithms for factor, scenario, or mixed factor and scenario...

Increased use of expectational data for modeling stock returns places a spotlight on the specification of predictor variables. Choices between alternative specifications of a given predictor such as E/P or earnings trend, for example, can have wide-ranging effects on portfolio selection and...

When they want to see how complex systems work, scientists often turn to asynchronous-time simulation, which allows processes to change sporadically over time, typically at irregular intervals. While rarely used in finance today, such models may turn out to be valuable tools for understanding...

That various “styles” of stocks perform differently suggests a strategy of rotating a portfolio's allocations across styles — growth, value, large-cap, and small — in line with changes in the economic environment. The issue then is how to define style. A “high-definition” approach...