It's not so simple as a magic section; AMT may or may not apply.
If you got the stock as a gift, or (more likely in this startup context) an RSU grant, the entire value is taxed as ordinary income at the time you receive the shares. I don't think there's any special AMT treatment here.
If you purchased the stock using NQOs (non-qualified options), the difference between the strike price and fair market value is taxed as ordinary income at the time of purchase, and again I don't think there's any special AMT treatment.
If you purchased the stock using ISOs (incentive stock options), then you have to watch out for AMT -- under normal rules, you don't owe tax at time of purchase, and when you sell, if you held long enough, the gain from strike price to FMV at purchase time may be taxed as capital gains. But under AMT rules, the purchase is a taxable event, and you may owe tax at exercise time.
Under any of these, if you exercise (or are gifted) shares and hold them and they decline, you may end up owing taxes on the higher on-paper value that never meant real money to you, and this ends up feeling unfair. But this case is generally obvious enough you would see it coming, except in the ISO+AMT case which is much less obvious, and this difference is what screwed a lot of people in the 2000-era bubble burst.
Normal disclaimer: I'm not a lawyer or accountant, there are many more details that apply here, and you need to figure out what applies to you before making any important decisions. But I believe the above is basically true.
If you got the stock as a gift, or (more likely in this startup context) an RSU grant, the entire value is taxed as ordinary income at the time you receive the shares. I don't think there's any special AMT treatment here.
If you purchased the stock using NQOs (non-qualified options), the difference between the strike price and fair market value is taxed as ordinary income at the time of purchase, and again I don't think there's any special AMT treatment.
If you purchased the stock using ISOs (incentive stock options), then you have to watch out for AMT -- under normal rules, you don't owe tax at time of purchase, and when you sell, if you held long enough, the gain from strike price to FMV at purchase time may be taxed as capital gains. But under AMT rules, the purchase is a taxable event, and you may owe tax at exercise time.
Under any of these, if you exercise (or are gifted) shares and hold them and they decline, you may end up owing taxes on the higher on-paper value that never meant real money to you, and this ends up feeling unfair. But this case is generally obvious enough you would see it coming, except in the ISO+AMT case which is much less obvious, and this difference is what screwed a lot of people in the 2000-era bubble burst.
Normal disclaimer: I'm not a lawyer or accountant, there are many more details that apply here, and you need to figure out what applies to you before making any important decisions. But I believe the above is basically true.