Why volatility arbitrage matters
It targets volatility more directly than a directional trade but depends on forecasting, dynamic hedging, costs, jumps, liquidity, and model assumptions.
How it is applied
A manager buys or sells options judged mispriced, delta-hedges directional exposure, and monitors gamma, vega, theta, skew, term structure, and realized hedging costs. Construct option and underlying positions intended to isolate a difference between implied volatility and expected or realized volatility. Traders hedge delta, monitor gamma, vega, skew, term structure, funding, and transaction costs, and define how forecasts respond to events and changing regimes.
Portfolio example
A trader buys an option at 18% implied volatility expecting 24% realized volatility and repeatedly delta-hedges. Profit depends on the price path and costs. A trader buys options implying 20% volatility and delta-hedges while the underlying later realizes 28% with sufficiently large moves. Gamma trading gains may exceed theta and costs. If realized volatility is 15%, the premium can decay faster than hedging profits accumulate.
How to interpret it
Buying low implied volatility and selling high is an oversimplification. Risk premium, jump exposure, skew, liquidity, and execution determine whether a gap is exploitable. Long volatility positions benefit from movement and often rising implied volatility, while short volatility collects premium but bears jump and convexity risk. Profit is not simply realized minus implied volatility because path, hedging frequency, skew, and costs matter.
Limitations and common misconceptions
Volatility can gap, correlations can break, and short options can create severe losses. Models omit risks and crowded hedges can move markets. This arbitrage is not risk-free. Continuous hedging is impossible, option liquidity varies, and models omit jumps and market closure. Implied volatility contains risk premiums that can persist. Short strategies can show many small gains before a catastrophic loss. Funding and margin calls can force exit before expected convergence. Return attribution should separate option carry, realized hedging gains, implied-volatility repricing, skew, and transaction cost. This shows whether profit came from the stated volatility edge or an unintended directional position. Stress scenarios need discontinuous gaps and volatility-surface shifts because local Greek hedges can fail precisely when the strategy faces its largest exposure.
Sources and further reading
- Introduction to Derivative PricingCFA Institute
- Valuation of Contingent ClaimsCFA Institute