keywords: stocks investors shares market brokerage
text: Stocks Finish Lower on Rising Oil Prices NEW YORK - A brokerage downgrade of several semiconductor companies pressured tech shares Thursday, while the broader market was little changed as a jump in jobless claims offset investors' relief over declining oil prices.    Late summer trading is known for being thin, but with the Republican National Convention set for New York next week, Wall Street is even less crowded than usual for late August...