"... and need to understand what amount I'm going to be taxed long term gains on based on the fact that I already paid AMT tax amount on 2015..."
The "AMT" aspect of the original acquisition means that nobody here can really answer your question definitively; you're going to have to fill out your income tax return to see what actually happens here.
For "regular" tax purposes you're going to sell the stock with a claimed basis of $.21 per share. For AMT purposes you're going to sell the stock with a claimed basis of $1.14 per share. You may very well get an AMT credit, or you may not; the devil is in the details in this case, details that nobody here, (a user to user group), know or understands.
Make sure you use the ISO step by step interview to report the sale in TurboTax. TurboTax will automatically enter the necessary adjustment to Form 6251 for the stepped up basis of the stock for AMT purposes.
Tom Young
