How Does a company make money through its IPO?

[John B]

The money comes from the investors that buy the shares initially. The underwriters don't own the shares, they just sell them.

Finally, in an IPO, the company does not sell all of its shares. Most of the shares go to the founders, employees, and early investors, or are just held by the company. If Facebook sells only 10% of its shares and they sell for $10 billion, then in theory the company is worth $100 billion because the shares that were not sold are worth the same as the shares that were sold.