Quote from dmo:
Yes, but what if there's huge volume, the price for the call swells - and a buyout is announced and the stock jumps 20%? Then it turns out that call wasn't so overpriced after all, was it?
The only sure way to know an option is overpriced or underpriced is relative to other options at nearby strikes. If I can buy USO 85's at 40% IV and sell the 86's at 42% IV, then I can say with confidence that the 86's are overpriced. Even then it's not absolutely certain I'll end up with a profit - but I'll take those odds any day. This gets back to delta neutral spreading strategies that are probably more appropriate for futures options than stock options.
Quote from c.chugani:
A couple of rookie questions here:
I am assuming your example for USO is regarding call options, therefore the 86's would be more OTM than the 85's. I get it you are talking about the skew that can be seen for options with less moneyness? But by that rule of thumb then, most OTM options will be overpriced relative to nearer to the money strikes (due to this skew). Is this what you are saying?
Also, what if you could sell the 86's for 42% IV but not be able to buy the 85's at 40% IV - is there no other means to determine whether the 86's you just sold were overpriced?
Quote from dmo:
Look at it this way. Gammas at the 85 strike are gammas at the 85 strike, whether in the form of puts or calls. If you can buy 85-strike gammas at 40% (in the form of calls) and sell 85-strike gammas at 41% (in the form of puts), that is an arbitrage. It's called a reversal.
Quote from c.chugani:
I see. What you have just described I have always thought of as a synthetic underlying position (either long in the case of long calls and short puts; or short in the case of short calls and long puts).
Quote from dmo:
Could be calls or puts. Doesn't matter. The point is to think of it as buying or selling gammas @ IV. As an example, instead of thinking of it as buying 85 calls at 1.45, think of it as buying 85-strike gammas at 40% IV. If you can sell 86-strike gammas at 42% IV, then you have bought something at one price and sold something which is ALMOST the same thing at a higher price.
Look at it this way. Gammas at the 85 strike are gammas at the 85 strike, whether in the form of puts or calls. If you can buy 85-strike gammas at 40% (in the form of calls) and sell 85-strike gammas at 41% (in the form of puts), that is an arbitrage. It's called a reversal.
Is there another way to determine overpriced or underpriced? Nothing certain, but there are some guides such as historic range. Since the VIX was created in 1990 it has never been over 50% so if you ever see it approach that level, it's probably overpriced. Then again, during the '87 crash it would have been about 150%. Ya pays yer money and takes yer chances.
Quote from increasenow:
seeking information...I honestly did not know what options trader look for when pricing and option...meaning saying "nah would not buy at that price as the _____ is too high or low" etc.