US private equity firm Kohlberg Kravis Roberts & Co will buy the world's largest credit card processor, First Data, in a deal worth a total of 29 billion dollars, the companies said Monday, according to dpa. The offer of 25.6 billion dollars, not including debt assumption, is the second-biggest leveraged buyout ever, after a 31-billion dollar KKR and TPG Inc takeover of power producer TXU Corp earlier this year, Bloomberg financial news service reported. First Data shareholders will receive 34 dollars in cash for each share, 26 per cent more than Friday's closing price. The agreement has been approved by the First Data board, but it can still solicit other offers for 50 days. Profits from ongoing business at the Colorado-based credit card payment processor were 848 million dollars last year, and revenue was 7.1 billion dollars.