I'd say there's a 99% chance it's already included in the W-2.  Back in the early days I used to see a lot of errors when it comes to equity compensation.  I still see some from time to time but if this is a big employer (i.e. GOOG, MSFT, AAPL) they know what they're doing.  If it's a small local bank . . . maybe not (I think that was the last one I saw that was wrong!)