Is volatility the same as risk? Algorithmic trading pros separate volatility into different measures of risk. So why didn’t Nobel Prize winner Harry Markowitz do the same?
View volatility risk from a different perspective
Scot Billington from Covenant Capital Management, a momentum fund with a 15 year track record with $500 million in management, thinks risk can be viewed from a different angle.
Markowitz and Sharpe did not distinguish between upside and downside volatility
Markowitz and his Nobel Prize winning colleague William Sharp both believe the higher the volatility the riskier the investment. In other words, the more an investment moves up and down in price the riskier that investment. At issue, however, is the treatment to upside vs downside volatility. Sharpe and Markowitz says positive volatility, when an investment is making money, has the same risk weighting as negative volatility, when an investment is falling. The popular thesis in the managed futures industry is that upside volatility has a lower degree of risk than negative downside volatility. This concept was discussed in 2010 in the book High Performance Managed Futures. The reason it is significant is that a momentum strategy, such as that utilized by Covenant or Cliff Asness at AQR is that sophisticated trend followers are known to have different risk management regimes for upside vs downside volatility. While the final trading formulas of most algorithms are closely guarded secrets, all algorithms can be categorized based on core market environment forces. Price persistence – or the price of an asset continuing to move in the same direction – is the market environment known to favor trend following.
Challenging a gang of Nobel Prize winners: Upside deviation carries less risk
This is the thinking challenging Nobel Prize winners Sharpe and Markowitz that Billington now brings to a head. In the Futures Magazine article, “This leads us to a different way to view risk. Risk is the difference between the anticipated worst loss and the realized worst loss,” Billington wrote. “When viewed through this lens, lower volatility equals higher risk.” Billington then considered various portfolios based on worst drawdown and volatility. The result of this exercise, well known in the managed futures industry, is that adding the proper dose of volatility to a program can actually reduce the overall portfolio volatility. It’s like eyeing your cake and eating it too. At the end of the day Markowitz and Sharpe received Nobel prizes for what is considered a faulty risk modeling algorithm. “Can Nobel prizes be taken back,” joked Lincoln Ellis from Green Square the $2 billion family office. Ellis utilizes volatility pairing to build portfolios designed to operate in both positive and negative stock market environments and considers upside volatility less risky than the downside variety.
