This paper examines how restrictions on short positions affect the financial attractiveness of factor investing. To fill the gap between unconstrained long-short allocations and restricted long-only portfolios, we consider two in-between strategies. The first imposes that only the market can be shorted; the second is the so-called “130/30” or “active extension” trading strategy, which caps total short exposure at 30%. The takeaways from our research are twofold. First, short sales contribute significantly to the mean-variance performance of efficient factor-based portfolios. Second, the factor portfolios built originally by Fama and French (1992) with the purpose of developing asset pricing are impressively clear-sighted when it comes to portfolio management. Indeed, combining these portfolios generates mean-variance performances similar to those of optimized long-short portfolios, except for low levels of volatility.
Amundi Working Paper - April 2017
