KKR & Co., the private-equity firm run by Henry Kravis and George Roberts, agreed to buy the publicly traded credit business KKR Financial Holdings LLC in a $2.6 billion transaction.

Investors will receive 0.51 KKR shares for each share in KKR Financial, valuing the public fund at $12.79 a share, a 35 percent premium to its closing price today, according to a statement Monday.

KFN has fallen more than 10 percent this year. William Sonneborn stepped down in July as chief executive officer of the business, and was replaced by Craig Farr, a capital markets executive at New York-based KKR.