Refining Portfolio Construction When Alphas and Risk Factors are Misaligned

Abstract

The misalignment of alpha and risk factors may result in inadvertent and unwanted bets that may hamper performance. Lee and Stefek (2008) show that better aligning risk factors with alpha factors may improve the information ratio of optimized portfolios. They propose four ways of modifying a risk model to reduce misalignment. Here, we discuss one way to mitigate these problems by modifying the optimization process, itself. The objective function is modified to include a penalty term on the residual alpha. In our examples, the method proposed helps to mitigate the mismatch between alpha and risk by assigning a suitable penalty to the residual alpha.

Keywords: portfolio construction, alpha risk, factors, construction, misaligned model, residual