By Kate Gibson, MarketWatch U.S. stocks on Tuesday started the new month in tentative fashion, holding near unchanged before a report that might illustrate U.S. manufacturing expanded at a slower pace for April. "Earnings are the key market support, but investors are unwilling to pay for future earnings when the economic and political climate is so cloudy," emailed Howard Silverblatt, senior index analyst at S&P Indices. The Dow Jones Industrial Average (DJI) fell 21.42 points to 13,192.21. The S&P 500 (SPX) shed nearly half a point to 1,397.52, with technology the strongest performer of its 10 industry sectors and industrials the greatest laggard. Sears Holding Corp. (SHLD) rallied 15% after the retailer said it expects to report a first-quarter operating profit later this month. The Nasdaq Composite (RIXF) rose 3.73 points to 3,050.14. Advancers edged just past decliners on the New York Stock Exchange, where 72 million shares traded as of 9:45 a.m. Eastern.