Google at 342.46, High of 344 It could have been a an expensive lesson in pin risk/position management. But cheaper than paying for an options course
Although I realize the OP would have lost money... I still don't see the "lesson" here. GOOG could've just as easily been at 342.46 Friday morning... there's nothing magical about today. If you hold any kind of a short position (including an ITM naked call), you will lose money when the stock goes up. That's just something you have to be ready for when you write calls.
The problem is if you have a good profit take it, trying to grab the last 13 dollars is kind of silly.
True... I don't know what his GOOG options were trading for on Thursday, but it was probably not much more than 13 dollars either. Why not close it out right then and there? Actually for my own purposes, I'd be curious if someone has good heuristics for deciding when's a good time to take money off the table when writing options. How do you balance the remaining time premium versus probability you'll lose?
Apart from the lesson that one should close out near the money options to avoid pin risk, the reason to look at it Monday AM post expiration is to familiarize oneself with the pre market trading, the wider spreads and the erratic behavior of many stocks due to the decreasing illiquidity of pre-market hours... just in case you need to close a position. IMHO, not only should everyone be familiar with pre/post hours trading but they should also have trading approval for them. With some positions, having the ability to adjust via long or short stock enables one to lock in profits (or cut losses) without being at the mercy of having to waiting until 9:30 AM EST and getting whatever price the underlying opens at.