By guest blogger Dr. Sebastian Ceria, CEO at Axioma, Inc.
As we have been vividly reminded of late, hedging is anything but easy. Indeed, it is one of the toughest challenges in all of risk management.
But it is also a challenge that everyone faces, regardless of whether one is a quant or a fundamental manager.
The concept is deceptively simple. Given a portfolio, reduce or neutralize that portfolio’s future risk and/or risk exposures by buying securities that are likely to behave in a manner opposite to those of the portfolio. To put it another way, the hedging process essentially involves finding securities that have negative correlations to the risk that you want to hedge.
For example, say your holdings have too much corporate debt. You would want to buy securities that will behave negatively to corporate debt. Hence, if the risk of corporate debt increases, your hedge kicks in and mitigates the overall risk increase.
Building a hedge can only be accomplished by a combination of history—looking at the past as an indicator of future behavior—plus a model whose job it is to forecast the behavior of your securities in the future.
We need three things to get started: an existing portfolio with risks we want to hedge, a risk model and a portfolio optimizer. The risk model serves as a proxy for the future behavior of those securities we want to hedge. The optimizer is used to build a basket of stocks that, when added to the existing portfolio, will reduce the undesired risks.
But here’s where things get “interesting.”
Axioma, for instance, offers multiple risk models—a short-term model, a medium-term model, a fundamental model and a statistical model. Depending on the model you choose, the result of the hedge could be quite different. Say you want to build a hedge for a month. Should you use a statistical model or a fundamental model? Should you use the short-term or medium-term model? Perhaps you want to build a hedge that works for three months. Now which model do you choose?
Let’s look at an example. Suppose we have constructed a low volatility portfolio by equi-weighting the 200 names in the Russell 1000 with the lowest Volatility score as measured by the Volatility factor in Axioma’s Medium Horizon, Fundamental Factor Risk Model. As with many low volatility/low beta portfolios, this portfolio has easily out-performed the Russell 1000 since 2000.
Suppose now, that we become even more risk averse and wonder if we can reduce the risk of this portfolio even further without degrading its performance significantly. We still want to have at least the same very low exposure to the Volatility factor – that is the bet we intend to make. But, all other things being equal and choosing only stocks within the Russell 1000 universe, can we reduce risk even further?
The answer, of course, is yes, but with other changes in the portfolio’s performance. Table 1 summarizes the performance of three portfolios: the Russell 1000, the original portfolio (equi-weighted, low 200 names), and the hedged portfolio1.
As designed, the realized risk of the hedged portfolio (9.9%) was less than that of the original portfolio (11.7%), both of which were less than the benchmark. The predicted beta of the hedged portfolio was substantially less than that of the original portfolio, indicating that the Volatility exposure of the hedged portfolio was even deeper than that of the original portfolio.
However, as often happens with hedged portfolios, the total return decreased relative to the original portfolio. As shown in Fig. 1, the hedged portfolio had similar returns as the original portfolio, but its performance lagged during the bull market of 2003 to 2007 and also in late 2010. This occurred because the hedged portfolio’s beta was lower than the original portfolio.
Although the total return of the hedged portfolio took a hit, its performance during the worst market downturns was better than the original portfolio. Figure 2 shows the maximum 30-day drawdown for the three portfolios.
Both the original and hedged portfolios had significantly less drawdown than the Russell 1000 in 2000 and again in 2007. The hedged portfolio, however, outperformed the original portfolio during the worst of the crisis in 2007 and 2008, with drawdowns that were 5% less than the original portfolios. So, as advertised, the hedge worked to protect the portfolio from the worst market downturns.
For quant practitioners who want to take their understanding of hedging strategies to higher levels, the Advanced Risk and Portfolio Management Bootcamp, August 13-18 in New York, is a great opportunity. The use of advanced mathematics and sophisticated analytics, such as stress testing, will be among the topics discussed in this intensive week-long program.
1 The hedged portfolio was constructed to minimize total portfolio risk by selecting stocks in the Russell 1000 and maintaining an exposure to Axioma’s Volatility factor that was at least as negative as the original portfolio. Asset holdings were long only, with a maximum of 3% for any security. Monthly rebalancing between 12/31/97 and 5/31/12.