as using smart beta. Another term for describing the investability of a risk factor is that it is tradable.
While many factors are tradable, they may not be fully implementable. For example, the value factor has been shown to be strongest for the very small-cap firms. However, there is limited capacity for investing in these firms, and the bid-ask spreads for their stocks are quite wide. Since creating the value factor would require frequent rebalancing of the portfolio, it may not be possible to fully implement factor investing in value stocks. Therefore, traded investment products designed to replicate the value factor tend to concentrate their allocations to large-cap stocks, which have shown to be poor representatives of the value factor.
Even when pure risk factors may not be fully traded, their return properties are useful in measuring risk exposures of investment products (e.g., hedge funds) and in determining if they offer any alpha. If one were to regress the excess return of an investment product against the returns of several traded factors, the intercept would represent the alpha of the investment product.
2.5.6 Risk Allocation Based on Risk Factors
How does one perform risk allocation based on risk factors? Factor or risk allocation is no different from asset allocation. After all, one has to use assets to isolate risk factors. Two issues related to factor investing should be considered. First, it is not possible to create a benchmark for a passive factor investing strategy. This is because factors involve long/short strategies, and therefore it is unclear what the passive weights of a diversified portfolio of factors should be. Should the factors be equally weighted, or should they be volatility weighted? There is no clear answer to this question.
Second, direct factor investing requires the investor to actively manage portfolios that are supposed to represent risk factors. Therefore, there is no such thing as passively managed factor portfolios. It should be pointed out that if there are enough investment products (e.g., funds and ETFs) replicating each risk factor, then the investor could follow a buy-and-hold strategy involving these investment products. However, unless one is willing to allow the weights of some factor to become very high or low, the investor will have to rebalance the portfolio on a regular basis. In addition, direct investments may not be a viable strategy for some institutional investors, as most factor strategies would require long and short positions in certain asset classes, and many institutional investors may not be prepared to take short positions.
Several hedge fund strategies earn their returns by exploiting these risk factors. For instance, the merger arbitrage strategy earns a premium by exploiting a risk factor related to the uncertainty surrounding the completion of mergers. The convertible arbitrage strategy exploits a form of the implied volatility factor, and many equity long/short and equity market-neutral strategies have been shown to have significant exposures to risk factors of the equity markets (Zhang and Kazemi 2015). Finally, global macro strategies often rely heavily on the carry trade factor to generate returns.
2.5.7 Performance with Allocations Based on Risk Factors
Do allocations based on risk factors outperform allocations based on asset classes? In theory, allocations based on risk factors should provide the same risk-adjusted return as allocations based on assets if the same information sets are used (Idzorek and Kowara 2013). It can be shown that in a perfect world, where all risk factors can be traded and all asset returns can be explained by risk factors, neither approach is inherently superior to the other. Research using real-world data has demonstrated that either approach may be superior over a given period of time (Idzorek and Kowara 2013). In particular, in some cases, the apparent superiority of risk factors is a simple result of the fact that risk factors can be conceptualized as being an alternative set of asset classes that can be identified when the long-only constraint is removed. For instance, a portion of the return earned by the value factor is due to the fact that it shorts growth stocks. Therefore, an asset allocation strategy that would permit the investor to short stocks should be able to match the performance of a portfolio that allocates to the value factor. If all risk factors were traded and short sale constraints were removed, then it would be difficult to imagine that a portfolio constructed using risk allocation could outperform a portfolio constructed using asset allocation on a consistent basis.
Several practical issues associated with risk-factor-based asset allocation must be highlighted (Idzorek and Kowara 2013). First, portfolio construction using risk factors is not likely to become globally adopted, because it implies allocation strategies that are not sustainable (i.e., not consistent on the macro level). That is, not everyone can be short growth stocks or commodities that are in contango. Therefore, the capacity is likely to be limited, and as more money is allocated to factor investing, the strategies will become expensive and the risk premium will shrink or disappear altogether. Second, risk allocation requires asset owners to take extreme positions in some asset classes. Many institutional investors are not allowed to make such allocations. For example, taking short positions in all growth stocks, including such names as Google, Amazon, and Facebook, is not something that most investors are prepared to do. Third, risk allocation is not a magic bullet that will automatically lead to asset allocations that will dominate those based on asset classes. Similar to other investment products, the cost of the strategy must be taken into account. Flows into some of these factors have already reduced the size of the premium (e.g., size and low volatility factors have not performed well in recent years). Finally, alternative investments are important vehicles for accessing some of these risk factors, but they typically represent a bundle of risk factors; as such, a pure risk allocation approach cannot be applied to alternatives. However, measuring factor exposures of alternative assets can provide valuable information about their risk-return profiles, which should be taken into account when allocations to traditional asset classes are considered. For instance, factor exposure analysis of private equity will highlight the fact that it has significant exposures to size and credit factors. Therefore, the investor may choose to tilt the exposure of the portfolio's traditional assets to other factors.
2.6 Conclusion
Chapter 1 introduced the basics of the asset allocation process and studied the mean-variance approach to asset allocation. This chapter extended the concepts discussed in Chapter 1 to take into account practical issues that arise while applying the asset allocation process. This chapter began with a discussion of tactical asset allocation (TAA), with a focus on the costs and benefits of this strategy when applied to portfolios of traditional and alternative investments. It was argued that because the rebalancing of alternative investments is costly, a higher level of skill is needed to make TAA a value-added activity.
Next, the chapter discussed several extensions to the mean-variance approach. The focus here was on those extensions that are important to alternative assets. For instance, we discussed how illiquidity and estimation risk can be taken into account when performing mean-variance optimization. While these extensions may not provide perfect answers, they represent excellent starting points to the asset allocation process and can serve as checks against other, perhaps more heuristic approaches that are adopted by asset allocators.
Risk budgeting and the risk parity approach were discussed next. Risk budgeting is a valuable tool for analyzing a portfolio's risk-return profile and imposing risk constraints desired by asset owners. Risk parity uses the results of risk budgets to create portfolios in which each asset contributes the same amount to the total risk of the portfolio. The chapter discussed the pros and cons of risk parity and pointed out that some of the reasons given in support of risk parity may not apply to alternative investments.
Finally, the chapter discussed factor investing. This is a relatively new topic in the investment community and, similar to other new ideas, has to be evaluated carefully when applied to alternative investments. The primary benefit of factor investing is that it informs investors that returns will come from being exposed to certain risk factors and allows asset owners to decide if earning returns through exposure to these certain risk factors is consistent with their objectives and constraints.
References
