FACTBOX- How private equity firms KKR, Blackstone stack up

(Reuters) - KKR & Co. LP KKR.UL has filed with regulators for an initial public offering, joining the recent high-profile listing of rival Blackstone Group LP (BX.N) last month.

Now, some of the secrets of financial powerhouses KKR and Blackstone have been revealed, ranging from how many people each employs to how much money each earned last year. Here is a brief comparison:

HISTORY:

Blackstone:

-- Founded by Peter Peterson and Stephen Schwarzman in 1985. Started with $400,000, after the two left brokerage Lehman Brothers.

Kohlberg Kravis Roberts & Co:

-- Founded by Henry Kravis and George Roberts in 1976, pioneering the leveraged buyout industry. Its 1988-1989 buyout of RJR Nabisco was immortalized in the bestseller "Barbarians at the Gate."

STAFFING:

Blackstone:

-- Firm has 770 employees. Headquarters are at 345 Park Avenue, New York, New York, with offices including Mumbai, Hong Kong, London, Paris, Boston, Atlanta, Los Angeles.

Kohlberg Kravis Roberts & Co:

-- Firm has 399 employees. Headquarters are at 9 West 57th St, New York, New York, with offices including Menlo Park, San Francisco, London, Paris, Hong Kong, Tokyo.

BUSINESS:

Blackstone:

-- Portfolio includes Freescale Semiconductor, TeleDanmark, The Nielsen Company, SunGard, Michaels Stores, Travelport, Pinnacle Foods, Deutsche Telekom, Equity Office Properties Trust.

Kohlberg Kravis Roberts & Co: