They only floated about 10% of their outstanding stock on a fully diluted basis. Twitter (the company) could have raised more, but individuals who owned the st

They only floated about 10% of their outstanding stock on a fully diluted basis. Twitter (the company) could have raised more, but individuals who owned the stock before the IPO still see the gain, unless they did a secondary market offering. Given the dangers of overpricing, it's a price worth paying. (If the stock falls in value on the first day of trading, it may lose its marketability with investors and hence even more of its value.)