Initial public offerings are as high as high finance gets. When a well-known, formerly private company goes public, investors clamor for shares. They already know the company’s management, they know its earning history, its forecasts. In many cases, the only thing left to chance is how much higher the share price will go once trading begins. They’re also the result of months or years of work. Companies turn to investment banks to underwrite the offerings, vet buyers, scintillate the media and value the stock. When it goes right, an IPO can mean a sudden infusion of cash in the tens of billions in just a matter of hours for some companies.