Around 62% of Americans own stock, whether directly or through retirement accounts like 401(k)s or IRAs, according to a Gallup survey. That's a majority, but it still means nearly four in ten adults have no stake in the market at all. Stock ownership in the U.S. isn't evenly spread, and factors like income, education and race  play the biggest roles in determining who invests and who's left on the sidelines. Main Factors Causing The Divide Among households earning $100,000 or more a year, about 87% own ...