The Globe and Mail reports in its Tuesday edition that Wall Street stocks posted modest gains on Monday as investors watched developments in U.S.-Iran peace negotiations and cheered the unveiling of a new computer chip that promises to bring artificial intelligence to personal computing. A Reuters dispatch to The Globe says tech shares rose 2.5 per cent, boosting Nasdaq and the S&P 500 to the latest in a series of record closing highs, while the blue-chip Dow closed nominally higher. The S&P/TSX Composite index ended down 34.25 points, at 34,734.89, with weakness in financials and materials stocks weighing on the Canadian benchmark index even as oil prices rose sharply. U.S. President Donald Trump said talks with Iran continue. Earlier, Iran's news agency announced Tehran was halting indirect negotiations with Washington after a new round of strikes threatened to derail diplomatic efforts to end the war, now in its fourth month. U.S. stocks added to their gains after Mr. Trump said no Israeli troops would go into Beirut, citing a call with Israeli Prime Minister Benjamin Netanyahu. Nvidia rose 6.3 per cent after the company unveiled a new chip that puts AI capabilities directly into personal computers.