U.S. stocks ended Tuesday's session to the downside as oil prices declined and Wall Street factored in a near-term rate increase. West Texas Intermediate crude oil settled lower by 1.34 percent to $46.35 a barrel. Investors are awaiting Wednesday's weekly reading on crude inventories, which are expected to increase. The S&P CoreLogic Case-Shiller U.S. National Home Price index rose 5.1 percent year-over-year in June, in line with May's increase. Fertilizer company CF Industries Holdings (CF) - Get Reportrose 4.4 percent, making it one of the best performers in the S&P 500, after Bloomberg reported that rival fertilizer makers Potash (POT) and Agrium (AGU) were in talks to merge. TheStreet's Scott Gamm reports from Wall Street.