Short seller Carson Block makes his living by spotting frauds. He made his name shorting the Chinese company Sino-Forest, and he tries to shine a light on companies that are total fakes and those that are stretching the truth. In a recent conversation with Business Insider, Block said that he was seeing less of the out-and-out frauds that led to a total collapse of a company but that a new trend worried him. NOW WATCH: FORMER GREEK FINANCE MINISTER: The single largest threat to the global economy