Private equity firms are capturing systems people in prison use and making them even more brutal and unaccountable. : Private equity firms are capturing systems people in prison use and making them even more brutal and unaccountable. Private equity firms, one of the most powerful arms of Wall Street, have become key adversaries of movements from labor rights to climate action to housing justice. With their wealthy CEOs and aggressive cost-cutting tactics aimed at delivering big returns, these firms are one of the most rapacious expressions of financial profiteering today.