More volatility in an asset means more opportunity for the price to move the right way and to achieve value for overlying warrants.
For covered warrant investors, volatility is good, a quality to be embraced, so there is no need to frown next time an earnest news reporter comments on highly volatile market conditions.
Historical volatility
Historical volatility measures the standard deviation of past movements in the underlying asset price. Volatility is a key input for ‘fair value’ analysis and for a number of other equations, so it is a useful figure to have to hand.
Most of the formulae are really seeking an estimate of future volatility, but in practice the extreme difficulty of forecasting such a thing means that historical volatility is used as a proxy.
For some guidance it is worth noting some of the current figures for major market indices and currencies, after a fairly tempestuous period. Figures for three-month and twelve-month historical volatilities at the end of July 2002, were as follows:
| Index | 3-month Volatility | 12-month Volatility |
|---|---|---|
| DAX | 44.27% | 30.66% |
| Dow Jones | 29.31% | 22.08% |
| Nasdaq | 48.51% | 42.45% |
| S&P 500 | 30.26% | 23.37% |
| Nikkei | 29.30% | 26.84% |
| EUR/USD | 10.38% | 8.83% |
| EUR/JPY | 8.04% | 9.05% |
There are a few interesting points to note from this table.
Implied volatility
Implied volatility is widely used as an indicator of value. The idea is quite simple. In the Black-Scholes equations, historical volatility was one of the five inputs used to determine a fair value price. That fair value price can then be compared with the actual market price to form a judgement on whether the market valuation is high or low. This is useful, but labour-intensive.
There is a simpler way, which is by using implied volatility. Instead of attempting to derive a fair value from the standard set of inputs, the current warrant price is substituted into the formula and the volatility omitted. It is then possible to work backwards through the equation to calculate a figure for volatility implied by the current market price.
The higher the market price of the warrant, the higher the implied volatility of the asset. Effectively the implied volatility is the expected future volatility of the asset over the remaining life of the warrant.
Comparing implied and historic volatilities
The time-saving when comparing a range of different warrants on one underlying asset is that the implied volatility calculated for each warrant can then be compared with one known variable – the historic volatility. Other things being equal, the lowest implied volatility would belong to the cheapest warrant, and more generally:
If implied volatility > historical volatility, warrant is expensive
If implied volatility < historical volatility, warrant is cheap
Volatility is not so important for warrants which are either well in-the-money or well out-of-the-money. Near-certainty of exercise or non-exercise means that the volatility of the underlying is far, far less important than the asset’s absolute performance.
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