These five either sell performance-fee funds or supply capital to the business: American Capital, Apollo Investment Group, Blackstone Group, Fortress Investment Group and KKR.

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Among the likely investment candidates: Cerberus Capital, Apollo Management, the Carlyle Group and the Blackstone Group.

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These include companies like American Capital ( ACAS), Apollo Investment Corporation ( AINV), Fortress Investment Group ( FIG), Ares Capital ( ARCC) and Fifth Street Finance ( FSC).

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Most of the other big private equity firms, like the Carlyle Group, Blackstone Group, Apollo Global Management, KKR and Oaktree Capital Management, now trade publicly.

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Steven Eisman of Frontpoint Capital delivered a scathing brief against for-profit education companies Corinthian Colleges, Apollo Group, ESI and Washington Post, saying they were creating the next subprime crisis by inducing students to borrow billions of dollars in federally guaranteed debt.

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