you are calculating the tax here at around 25%. Wouldn't this count as long term capital gains tax (if you hold the stock for more than 1 year, which it seems likely since the company was incorporated in 2007) that is currently being taxed at 15%?
State/City long term capital gains in NY are around 11-12%. In California they are the same as the income tax rate of 9.3%. 25% is the blended Federal/State/City rate.
Chances are the options weren't restricted options that employes could exercise ahead of time and that there was a 4 year vesting cliff. Most people don't exercise options at vesting time so I'd bet that most of the options were taxed as short term capital gains (and that would mean that 25% is actually probably a bit low for most employees with where this would get them to).
