Payment processing giant First Data Corp. is allegedly planning to raise $3 billion in an initial public offering, the biggest US listing so far this year. This IPO would kick off what could be a string of big deals for private equity firms that are seeking to tap into strong stock prices before a possible increase in interest rates makes highly indebted companies a less attractive bet. "Rising interest rates will eventually depress pricing," said Hugh MacArthur, the leader of Bain & Company's global Private Equity practice. Those higher debt costs "could make exits at the current record high multiples challenging."