Wall Street's main indexes opened higher on Thursday on news that the United States was on the verge of signing a trade agreement with Britain, while chip stocks added to gains on the prospect of fewer export curbs on AI semiconductors. The Dow Jones Industrial Average rose 198.6 points, or 0.48 percent, at the open to 41,312.57. The S&P 500 rose 32.3 points, or 0.57 percent, at the open to 5,663.6 , while the Nasdaq Composite rose 182.0 points, or 1.03 percent, to 17,920.154 at the opening bell. REUTERS