I have received some stock option grant which will vest over a period of 4 years, 25% will vest in one year, if I don't sell it after vesting, do I pay taxes (AMT) for the gains or do I pay AMT/Taxes only when I sell it.For e.g Strike price : $10, one year later $100. Do I pay taxes on $90 paper gain or only when I sell it.

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Yahoo!