[NEW YORK] Wall Street stocks opened slightly higher Wednesday in cautious trade ahead of Thursday's British vote on whether to exit the European Union.
The "Remain" camp has a razor-thin lead - 51 per cent versus 49 per cent for "Leave", according to an average of polls compiled by What UK Thinks.
The awareness of the risk of a "Leave" outcome "has presumably tempered the buying interest that swelled on Monday," said Briefing.com analyst Patrick O'Hare.
"It hasn't killed the buying interest, however."
Federal Reserve Chair Janet Yellen was set for a second day of congressional hearings after Tuesday's appearance before a Senate panel yielded no major surprises.
Five minutes into trade, the Dow Jones Industrial Average was up 0.2 per cent at 17,865.89.
The broad-based S&P 500 climbed 0.2 per cent to 2,092.56, while the tech-rich Nasdaq Composite Index added 0.1 per cent at 4,849.03.