As the co-founder of Kohlberg Kravis Roberts & Co., Henry Kravis pioneered the buyout business in the '70s and has managed to remain at the top of the game for decades. His wife is economist Marie-Josée Kravis.

Kravis started Bear Stearns thanks to his cousin, George Roberts, who worked at the firm. Both men found a mentor in Jerome Kohlberg, who taught them about the "bootstrap acquisition," the name for leveraged buyouts back then; four years later, the three joined together to found Kohlberg Kravis Roberts & Co., which became one of the early pioneers in the LBO business. KKR made its name in the 1980s thanks to a handful of mega-deals. In 1986, the firm orchestrated the $8 billion buyout of Beatrice Foods; two years later, Kravis worked on his most famous deal, the $31 billion hostile takeover of RJR Nabisco, an epic battle chronicled by Bryan Burrough and John Helyar in Barbarians At The Gate. Kravis was transformed into one of the most prominent financiers in town, but the 1990s proved to be a mixed bag for the LBO giant. While several buyouts yielded significant returns, there were a number of notable losers, too, including Regal Cinemas, Spalding sporting goods, and the magazine publishing giant K-III Communications (later renamed Primedia). Nonetheless decades after its founding and despite the financial crisis, KKR remains the gold standard in private equity circles. [Image via Getty]