We all know options are derivatives, and their prices are derived from the underlying stock, index, or ETF. But with other factors at work such as implied volatility, time decay and the constant changing of prices, it may be difficult to gauge how much option prices will change. Certainly these are all important factors to consider when pricing options. But have you ever wondered how much an option is going to change with respect to say the underlying? Very simple – check out its delta.
Delta is arguably the most heavily identifiable Greek (unless you count Socrates or Aristotle) especially by individuals learning to trade options. It offers a quick and relatively easy way to tell us what to expect from our option positions as we watch the price action of the underlying. Calls have positive deltas, as they typically move higher on a rise in the stock, and puts have negative deltas, as they typically move lower when the stock rises.
While some investors view delta as the percentage chance an option has of expiring in-the-money, it is really more of a way to project expected appreciation or depreciation. A delta of 0.50 for an AAPL call option suggests the option should move 50 cents higher when the AAPL moves up by a dollar, and lose 50 cents for every dollar AAPL moves lower.
But delta is only foolproof when all other factors are held constant, which is rarely the case (and certainly never the case for time decay). As option traders know, time decay is inevitable for all options particularly hurting long positions due to option premiums shrinking due to the passing of time. If an option is moving more (or less) than its delta would suggest, it is likely because other variables are shifting. For example, buying demand might be pushing implied volatility higher, raising the price of the options.
Still, this king of all Greeks is a good starting point for gauging how your options are likely to move. Option traders should consider mastering this option greek before moving on to the other greeks. Here at Market Taker Mentoring, we have many programs to teach you about option delta and much much more about all things options by experienced professionals. As Socrates once said, “Employ your time in improving yourself by other men’s writings, so that you shall gain easily what others have labored hard for.”
Senior Options Instructor