Billionaire investor Warren Buffett has said that he continues to look for a major acquisition for Berkshire Hathaway, but he's not willing to pay more to compete with other bidders. Buffett says Berkshire has lost out on a couple of major acquisitions in recent years because private equity firms bid aggressively with borrowed money. Berkshire doesn't borrow for acquisitions. The Berkshire chairman and CEO said Wednesday during an interview on CNBC that Berkshire has about $40 billion cash on hand. Buffett said that Berkshire has made about 15 smaller acquisitions this year. He called them “bolt-on acquisitions” because they just add to Berkshire's existing businesses. He also said that he has added to Berkshire's Wells Fargo and IBM stock investments this year, but he'd still prefer to make a big acquisition.