If you have been on an options trading floor, you may have heard comments like these for example. “What’s your delta of of the Cubs winning today?” (not good of course) or “What’s the delta the broker comes back and buys more of these?” Option traders have probably used the word delta in this context every single day of their life and if you learn to trade options like a professional, you may too.
It’s the “traders’ definition” of delta—that is, delta is the likelihood of an option expiring in-the-money. Though this definition actually has a few mathematical and theoretical shortcomings, making it not entirely technically correct, every professional option trader I know or Dan knows thinks about delta this way. Many if not most traders borrow the concept of delta being the likelihood of success and adapt into their every-day speech.
The idea is every option has an associated delta figure attached to it. Like, at the time of this writing, the Google Inc. (GOOG) May 830 calls have a 0.30 delta. That means that they change in value 30 percent like the GOOG stock. But it can also be interpreted by traders to mean that the GOOG May 830 calls have a 30-percent chance of expiring in-the-money.
This practical and “traders” use of delta helps guide traders’ expectations and helps them make better trading decisions by factoring probability into their decision-making process. I encourage retail traders to think about option delta this way. You should start today and see if it affects how you think about options and the possible different strategies that can be implemented. I’m 100 delta that you’ll be happy you did.
Senior Options Instructor