Many traditional equity managers focus on particular subsets of the investment universe – value or growth stocks, for example – and structure their portfolios from pre-selected groups. A different approach is argued here, one that takes advantage of the widest possible equity universe and...

Seemingly infallible arbitrage strategies can fail. When they do, they can take the markets down with them. The near collapse of Long-Term Capital Management parallels the experience of portfolio insurance in 1987

Firms that use one valuation model for their core portfolio and different models for subsets of that core may end up with multiple estimates of alpha. But as every asset has only one price, doesn't it follow that the asset should have only one mispricing? It is argued here that it hardly makes...

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...

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...

This editorial, which mirrors Bruce Jacobs's book Too Smart for Our Own Good: Ingenious Investment Strategies, Illusions of Safety, and Market Crashes, finds that “free-lunch” strategies and products that promise to increase returns while reducing risk can attract substantial investments and...

An asynchronous discrete-time model run in "dynamic mode" can model the effects on market prices of changes in strategies, leverage, and regulations, or the effects of different return estimation procedures and different trading rules. Run in "equilibrium mode," it can be used to arrive at...

The mean-variance-leverage (MVL) optimization model (Jacobs and Levy 2012, 2013a) tackles an issue not dealt with by the mean-variance optimization inherent in the general mean-variance portfolio selection model (GPSM) — that is, the impact on investor utility of the risks that are unique to...

Leverage entails a unique set of risks, such as margin calls, which can force investors to liquidate securities at adverse prices. Investors often seek to mitigate these risks by using a leverage constraint in conventional mean-variance portfolio optimization. Mean-variance optimization,...

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...