The trade deficit in the U.S. shrank more than forecast in October as a weaker dollar and growing economies overseas propelled exports to a two-year high. The gap narrowed 13 percent to $38.7 billion, less than the lowest estimate of 78 economists surveyed by Bloomberg News and the smallest since January, Commerce Department figures showed today in Washington. Exports were the strongest since August 2008 as Mexico and China bought record amounts of U.S. products. 3M Co. and General Dynamics Corp. are among companies that will probably benefit from growing demand in markets like China, Brazil and South Korea, which this year are among the top-10 buyers of American-made goods. Imports stagnated in October as U.S. demand for crude oil plunged, an outcome that may prove to be temporary as the world’s largest economy picks up.