Once an obscure niche of the investment world, private equity has grown into a juggernaut, with consequences for a wide range of industries as well as the financial markets. Private equity funds control companies that represent trillions of dollars in assets, millions of employees, and the well-being of thousands of institutional investors and their beneficiaries. Even as the ruthlessness of some funds has made private equity a poster child for the harms of unfettered capitalism, many aspects of the industry remain opaque, hidden from the normal bounds of accountability.