Canadian stocks whipsawed between gains and losses at Monday's open after the collapse of trade talks with the United States unleashed what threatens to become a widening trade war. Prime Minister Justin Trudeau recalled his negotiators from Washington as tensions escalated.

The S&P/TSX Composite Index whipsawed in early trading Monday and was little changed at 10:01 a.m. in Toronto after falling as much as 0.3%. Declines in industrial and consumer-discretionary stocks were offset by gains in the materials sector as gold miners gained.

Tractor trailers cross the Canada-U.S. border in Surrey, British Columbia. The breakdown in negotiations has heightened concerns about escalating tariffs and their impact on Canadian markets.

The materials sector's resilience, driven by rising gold prices, provided a buffer against broader market uncertainty stemming from the deteriorating trade relationship between Canada and the United States.