OP isn't gaining any money from this. They are excercising their options: spending $X0,0000 to buy $X,000,000 worth of shares. After exercising, they now own s

OP isn't gaining any money from this. They are excercising their options: spending $X0,0000 to buy $X,000,000 worth of shares. After exercising, they now own shares. The difference between the purchase price and the value of the shares is income, and OP needs to pay taxes on that income. Note that OP isn't getting money, they are getting the shares, which they can hopefully sell in the future, either in an IPO or acquisition (or future internal round). If they want to sell the shares to get money (to pay the taxes), there are tricky rules involved.