FRM Part II · FRM Exam Part II · Volatility Smiles and Volatility Surfaces
A bank's Black-Scholes model uses a flat 20% volatility to price a 1-year European call with a strike far above the current spot, while the market-implied volatility for that strike is 26%. The bank sells the call at the model price and delta-hedges continuously. Assuming the market's implied volatility is the fair price of risk and realized volatility turns out to equal 20%, which statement best describes the result?
If realized volatility equals 20%, hedging replicates a 20% volatility option, so selling at the 20% model price breaks even on the hedge. The bank's only shortfall is the forgone premium relative to the 26% market price, an opportunity cost rather than a hedging loss.
- AThe bank sold the option too cheaply relative to market, but if realized volatility is 20% the delta-hedged position earns roughly the model premium, so the shortfall versus 26% was an opportunity cost, not a hedging lossCorrect
- BThe bank loses money on the hedge because delta hedging fails whenever realized volatility differs from implied volatility in either direction
- CThe bank earns a profit equal to the difference between 26% and 20% volatility applied to the strike
- DThe bank is unaffected because the position is delta neutral and delta-neutral positions have zero value
Explanation
Delta hedging at realized volatility of 20% replicates a 20% volatility option, so selling at the 20% price covers the hedging cost with no gain or loss. The shortfall is only relative to the 26% market price at which it could have sold. The other options misstate hedge results or misuse delta neutrality.
Did you get it right without looking?
One question tells you little. A timed set on Volatility Smiles and Volatility Surfaces shows your real accuracy, how long you take and where you lose marks.
More Volatility Smiles and Volatility Surfaces questions
- A bank's volatility surface for a stock index shows a pronounced skew at the 1-month maturity but a nearly flat profile at the 5-year maturi…
- Implied total variance is sigma^2 times T. At-the-money implied volatility is 20% for a 1-year option and 22% for a 2-year option. Assuming …
- A trader finds that the implied volatility surface for a stock shows a much higher implied volatility for a 90-day option at one strike than…
- A one-year European call and put on a non-dividend stock share the same strike K and maturity. The put's implied volatility is 28%, and the …
- A trader notes that a one-month GBP/USD option smile is quite pronounced while a five-year option smile on the same pair is much flatter. Wh…
- Which assumption of the Black-Scholes model is most directly violated when a stock price can jump suddenly following an earnings surprise, l…