U.S. markets ended the last trading day of July sharply lower. The Dow Jones Industrials dropped more than 300 points. All the major benchmarks wiped out July's gains. Investor concerns were fueled by the global economy including Europe and an Argentine default mixed with a rate hike at home coming sooner than expected. Exxon Mobil (XOM) was the Dow Industrial's biggest decliner. Conoco Phillips (COP) also reported higher-than-expected profit but its stock also slipped 2.5%. Disappointing results also had investors selling out of Whole Foods Market (WFM) and Kraft Foods (KRFT). On Friday, investors will have a day loaded with economic data including the July Jobs Report along with numbers on Personal Income and Spending. Earnings on tap for Friday include Procter and Gamble (PG), Chevron (CVX) and Clorox (CLX). TheStreet's Susannah Lee has details.