U.S. stocks are headed for a lower opening Tuesday, although prices could later improve on news that wholesale prices rose less than expected last month and that the U.S. trade gap unexpectedly narrowed during July. Stocks have been on the rise since this month, and selling pressure early Tuesday is likely to signal only a small pullback. The December futures contracts for the Dow Jones Industrial Average, the S&P 500, and the Nasdaq 100 were all pointing toward fairly heavy losses in the early minutes of trade. The futures contracts were little changed after news from the Labor Department that wholesale prices increased 0.6% in August, beneath the 0.7% advance expected by analysts polled by MarketWatch. Core prices, which strip out food and energy prices, were unchanged. MarketWatch had forecast a 0.1% gain in the core rate. Separately, the Commerce Department said that a record amount of U.S. goods and services sold overseas helped narrow the U.S. trade gap in July despite the record high cost of foreign oil, the government reported Tuesday. The nation's trade deficit narrowed in the month by 2.6% to $57.9 billion, the Commerce Department said. The MarketWatch forecast was for the deficit to widen to $59.5 billion.