Day trading relies on both the daily ups and downs of the stock market on its way to settling at a level at or near where it started. Since day trading involves timing fund exchanges involving domestic stock funds within retirement savings plans, the discussion hereafter will primarily focus on U.S. market conditions. The rocky, but ultimately flat, performance of the broad stock market during the first decade of the new millennium provided pretty close to optimal conditions for day trading. This chapter touches on the forces expected to bring about the continued volatility and sideways direction of the stock market through at least 2020.