Wall St set to snap four-day rally as worries seep in

Wall Street was set to open lower for the first time in five days as investors sought shelter in safe-haven assets amid a drop in oil prices and global growth worries. U.S. government bond yields were at an all-time low as weak data from China added fuel to the uncertainty stemming from Britain's vote to leave the European Union. Data from China showed that the country's services sector activity rose to an 11-month high in June, but a composite measure of activity including manufacturing fell to