(Updates to open) Aug 17 (Reuters) - Canadian stocks extended losses for the fourth straight session on Tuesday, with the main TSX index hitting a one-week low as domestic and global economic data raised concerns about a slowing recovery. The Toronto Stock Exchange’s S&P/TSX composite index fell 0.5% to 20,390 in morning trade. Losses were broad-based, with healthcare, industrial, consumer discretionary and materials sectors all falling between 0.6% and 1.5%. Wall Street’s main indexes tumbled almost 1% after data showed U.S. retail sales fell more than expected in July as shortages weighed on purchases of motor vehicles. Meanwhile, commodity prices remained under pressure as investors feared a hit to demand due to a spike in COVID-19 cases in the United States and several Asian economies. “With the resurgence of COVID around the world, especially in the United States and even to a lesser degree in Canada, we’re seeing the reopening stocks start to pull back,” said Allan Small, senior investment adviser at Allan Small Financial Group. “This whole notion of reopening trade is being called into question.” Data showed Canadian housing starts fell 3.2% in July, compared with the previous month, as a drop in multiple urban starts outweighed an increase in single-detached urban ones. On investors’ radar will be the domestic inflation data due on Wednesday, which will be perused for clues on the Bank of Canada’s policy outlook. Hopes of a steady economic recovery and strength in corporate earnings pushed Toronto stocks to record highs just last week, with energy and financial stocks among the biggest drivers this year. HIGHLIGHTS * Westshore Terminals Investment Corp jumped 3.3% to the top of the TSX after the marine port service provider’s subsidiary entered into a conditional agreement to provide services to BHP Canada Inc. * Lithium miner Lithium Americas Corp fell 4.3% to the bottom of the TSX. * The TSX posted seven new 52-week highs and two new lows. * Across all Canadian issues there were 31 new 52-week highs and 16 new lows, with total volume of 30.82 million shares. * On the TSX, 46 issues were higher, while 174 issues declined for a 3.78-to-1 ratio to the downside, with 16.44 million shares traded. (Reporting by Amal S and Sruthi Shankar in Bengaluru and Sriraj Kalluvila) Our Standards: The Thomson Reuters Trust Principles.