E Finance Blog


Know When To Buy Or Sell An Option

October 11th, 2007 by admin

Today’s options markets are very efficient and options tend to be “fairly priced” at all times. As such, options are rarely, if ever, over or under priced.

Option are, from time to time, relatively expensive or inexpensive. However, just because an option is expensive does not mean that it is “over priced” as there may be a very good reason why the option price has increased. Conversely, there may also be very good reason why an option is relatively inexpensive.


As the market becomes more concerned about future price movement, there is a willingness to pay more for options to protect equity positions or to take advantage of anticipated price movement. Once those concerns pass, option prices will likely fall to lower levels.

This discussion requires a study of how implied volatility can be used to assess option prices in the market. An option price is only “cheap” if you expect implied volatility to increase during the lifetime of that option. Conversely, an option is only “expensive” if you expect implied volatility to fall during that same period of time.

You can quickly determine the current implied volatility for any option through any decent options broker. Once you know what the current implied volatility is for an option, you can then compare it to where implied volatilities have been in the past. You can also compare current implied volatility to the historic volatility of the underlying security.


When comparing current implied volatility to where implied volatility has been in the past, you are looking at the changing market expectations for the future volatility of the underlying security. As IV rises, it reflects greater uncertainty and concern in the market for the future price movement of the underlying stock.

For example, you might see IV rise as a key earnings date approaches followed by a return to prior levels once the news breaks. That news may be the catalyst for a large price move, up or down, or it may unfold as a non-event despite the heightened uncertainty that preceded it.

A comparison of implied volatility to the historical volatility of the underlying security allows you to assess whether the market’s expectations are consistent with what the stock or index has done in the past. As we have all read in any prospectus or financial disclaimer, past performance is not an indication of future results.

So, if you see IV rising or falling relative to historic volatility, it does not mean that the option is “over” or “under” priced. Rather, it should prompt you to question why the market is pricing in a greater or lesser amount of future volatility. Once you identify the catalyst for the IV change, you can then determine whether you want to be long or short vega.

There are several tools out there that can assist you in this analysis. The “right” tool is largely a function of personal preference. Your goal is to assess current implied volatility for purposes of determining whether you prefer being a net buyer or seller of options.

Discover how [http://www.theoptionclub.com/implied_volatility.html ]Implied Volatility is assessed with the Options University Volcone and ChartBender Pro and learn how IV can impact your trading decisions.

Posted in Investing category.