(KKR story updated with background information.) NEW YORK ( TheStreet) -- Kohlberg Kravis Roberts' parent, KKR, is readying a $2.21 billion initial public offering in the U.S. KKR said it would offer almost 205 million common units for sale. The private-equity firm plans to list on the New York Stock Exchange under the symbol "KKR." In July 2007, KKR had announced plans for an IPO, but put them on hold as the financial crisis hit the markets. KKR had $52.2 billion in assets under management as of December 31, 2009. -- Reported by Andrea Tse in New York Follow TheStreet.com on Twitter and become a fan on Facebook.