Many option traders will refer to the trifecta of option greeks as delta, theta and vega. But the next most important greek is gamma. Options gamma is a one of the so-called second-order options greeks. It is, if you will, a derivative of a derivative. Specifically, it is the rate of change of an option’s delta relative to a change in the underlying security.
Using options gamma can quickly become very mathematical and tedious for novice option traders. But, for newbies to option trading, here’s what you need to learn to trade using gamma:
When you buy options you get positive gamma. That means your deltas always change in your favor. You get longer deltas as the market rises; and you get short deltas as the market falls. For a simple trade like an AAPL January 565 long call that has a delta of 0.51 and gamma of 0.0115 , a trader makes money at an increasing rate as the stock rises and loses money at a decreasing rate as the stock falls. Positive gamma is a good thing.
When you sell options you get negative gamma. That means your deltas always change to your detriment. You get shorter deltas as the market rises; and you get longer deltas as the market falls. Here again, for a simple trade like a short call, that means you lose money at an increasing rate as the stock rises and make money at a decreasing rate as the stock falls. Negative gamma is a bad thing.
Start by understanding options gamma from this simple perspective. Then, later, worry about working in the math.
Happy New Year!
Senior Options Instructor