Financial markets are critical to the world economy, and the growth of financial exchanges has been impressive in recent years. Companies like CME Group (NASDAQ: CME) and CBOE Global Markets (NYSEMKT: CBOE) have dramatically expanded their initial scopes to go beyond their futures and options origins, taking on a wider range of financial products to try to cash in on rising interest among institutional and retail investors.Even though the bull market in stocks has continued for nearly a decade now, though, the future isn't guaranteed for these two exchange stocks.