Blackstone listed on the New York Stock Exchange during the summer of 2007. Doing so just before the global financial crisis was hardly auspicious, and come early 2009 the firm’s shares had lost almost 90% of their value. By the time the two other members of America’s private-markets troika rang the bell, Wall Street had been battered. KKR listed on July 15th 2010, the same day Congress passed the Dodd-Frank Act, overhauling bank regulation. Apollo followed eight months later. Each firm told investors a similar story: private equity, the business of buying companies with debt, was their speciality.