The Canadian dollar was heading for its worst day against the U.S. dollar in more than two months after trade talks between the two countries collapsed. The loonie fell as much as 0.6% to C$1.3844 versus its U.S. counterpart, leading losses against all Group-of-10 currencies and on course for its worst performance since June 17. Selling could extend, as Trump's latest 50% tariffs on billions of dollars of Canadian goods threaten an economic pickup expected in the coming months, according to market watchers.