Canadian stocks started the new week on a negative note as renewed U.S.-Iran conflict over the weekend briefly revived geopolitical concerns and kept commodity markets volatile. Although Washington and Tehran later agreed to halt further attacks and resume talks aimed at preserving their June 17th memorandum of understanding, investors remained cautious as both sides continued to send mixed signals about the diplomatic process. As a result, the S&P/TSX Composite Index plunged by 156 points, or 0.4%, on Monday to settle at 34,824.
Despite gains in some healthcare and financial stocks, declines in other key sectors, such as technology, consumer staples, and consumer cyclicals, weighed on the broader market and dragged the TSX index lower.
Top TSX Composite movers and active stocks
Brookfield Business Holdings, Aya Gold & Silver, NovaGold Resources, and B2Gold were the worst-performing TSX stocks for the day, with each falling by at least 4.3%.
On the brighter side, BlackBerry, goeasy, 5N Plus, and MDA Space climbed by at least 7% each, making them the day’s top-performing TSX stocks.
Shares of Aecon Group (TSX: ARE) also trended higher after announcing a deal to buy Oaktree Capital Management’s remaining 27.5% stake in Aecon Utilities for $320 million, giving it full ownership of the fast-growing utility infrastructure business.
Aecon said the transaction will strengthen its exposure to electrical, communications, and pipeline infrastructure markets, while simplifying its capital structure. The company also expects the deal to be immediately accretive to its adjusted earnings per share and says it will fund the purchase using existing cash and available credit facilities. So far in 2026, ARE stock has risen 43%.
Based on their daily trade volume, Canadian Natural Resources, BlackBerry, Telus, TC Energy, and Manulife Financial were the five most active stocks on the Toronto Stock Exchange.
TSX today
Commodity prices were largely bullish in early trading on Tuesday, with copper, silver, and crude oil showing strength. This broad-based strength in commodities could provide support to the resource-heavy TSX at the open today, especially for mining and energy shares.
Besides Canada’s monthly gross domestic product (GDP) data and the latest U.S. job openings figures, TSX investors will keep a close watch on developments surrounding U.S.-Iran diplomatic talks, as well as any movements in commodity prices.
With Canadian markets closed on Wednesday for Canada Day, trading volumes on the TSX could remain lighter than usual today as some investors reposition portfolios ahead of the midweek holiday.
Market movers on the TSX today
