The performance of the U.S. stock market in 2015 has been impressive. Not because stocks have made huge gains. They haven’t. The S&P 500 is down about half a percent for the year. Rather, stocks have been impressive because they have climbed many significant walls of worry while index levels have treaded in place. Many investors may be lulled into thinking that the rest of 2015 will be similar – relatively low volatility, the ability to deal with known issues, and the expectation of better earnings and economic data for the second half of the year. All of that may be true, but investors should frame their decisions by knowing the six obvious market risks. Those risks are: interest rates, geopolitics, corporate earnings, financial stability in China, a possible default by Puerto Rico, and the potential exit of Greece from the Euro and European Union.