Hello, I read on ET some time ago a basic rule of thumb for ITM call/put early exercise, but I couldn't find it again in the search. I was hoping someone could remind me of it. It was something like if the remaining extrinsic value was very low (or something along those lines), there was a high probability the ITM option would be called away. Anyone? I was looking at some spreads that would be traded on American style options (I've traded European's before). Short options being called away if ITM (as part of an overall unrealized profitable spread) was a concern of mine. Thanks in advance.