I've wondered about this before--what is the meaning of the _worth_ of options for ISO treatment? Suppose you have ISOs for five shares, with a strike price of

I've wondered about this before--what is the meaning of the _worth_ of options for ISO treatment? Suppose you have ISOs for five shares, with a strike price of $1: the company goes public, becomes Berkshire Hathaway, time passes, and the stock is now worth $101,000 per share. You exercise one option and immediately sell one share. Do the other four shares remain ISOs?