During her Congressional testimony, Fed Chair Janet Yellen painted a fairly bright picture of the US economy, stressing a rebound in consumer spending, which should allow the central bank to gradually raise short-term interest rates over the next few years. Investors were heartened to hear that message and drove stocks higher, with the Dow closing at a new all-time high after Yellen’s first day of testimony. What could undo this rosy picture? There are a number of risks to the US and global markets that persist, though three rise to the top of the list. Their existence does not mean that long-term investors should change their game plans, but they are a reminder to guard against complacency and to always approach investing with caution.