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Volatility is often the most
neglected of the major factors that influence option prices.
But we make sure never to make that mistake when we consider
possible trade recommendations. Volatility is a vitally
important consideration in options trading.
Every asset has quiet
periods when its options are cheap, and volatile periods when its
options are expensive. Professional option traders are always
aware of current volatility levels in relation to their historical
context. To gain that perspective, they view historical
volatility charts. The figure below shows a sample Volatility
Chart for Corn:

The Volatility Chart
displays two lines - one for statistical volatility (SV) and the
other for implied volatility (IV). The solid SV line
represents, at each point the actual volatility of the futures’ daily
price volatility. Statistical volatility is often
referred to as
“historical” volatility, but many prefer the term statistical since
volatility charts contain historical data for both SV and IV.
The dashed IV line represents, at each point, the average implied
volatility for the futures.
In other words, the SV
line shows you the actual volatility of the futures, while the IV line
shows you the volatility implied by the prices of the options of
that futures. They should normally be fairly close
together. If they are not, it would indicate the price of the
options is not reflecting the actual volatility of the futures.
At the bottom of the chart is a table that summarizes the average SV
and IV for various time periods.
Volatility Charts are
also useful for determining what “normal” volatility is. This
can help you profit when current volatility temporarily goes much
higher or lower than in the past. It can also be useful for
spotting patterns in volatility you can take advantage
of.
The price of a futures can
range from zero to infinity. Volatility cannot range that
far. The investor can always count on volatility eventually
returning to normal levels after going to an extreme. This
principle is called “the mean reversion tendency of
volatility”. It may take anywhere from days to months, but
sooner or later volatility always comes back to middle
ground.
Generally, implied
volatility tends to increase as futures prices decline, and decreases
as the futures prices rise. The reason this occurs is because
falling futures prices mean greater uncertainty with regards to future
risk. This leads to an institutional demand for insurance
against future losses, meaning a higher demand for put
options. This demand for puts drives implied volatility
upward. On the other hand, increasing futures prices mean less
uncertainty and subsequently less demand for put options resulting
in lower implied volatility.
This knowledge is very
useful for option buyers. For instance, while the value of a
call will increase with the futures price, the relationship between
price and volatility means the call will lose some (sometimes a
lot!) of its value due to the falling volatility. It is good
news for put buyers, however, because puts will increase in value
from the double effect of falling prices and increasing
volatility.
At times, implied volatility
and statistical volatility will be in close agreement, while at
other times one soars way above the other. You should always
be aware of current news on the futures you are
trading.
Sometimes events can
overwhelm historical volatility patterns. Be careful of
situations where implied volatility is high and statistical
volatility is extremely low. For example, if a crop report is
due out or if Alan Greenspan is about to speak.
In general, unusual events
can be treacherous for options traders – so be
careful!
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