Shares of railroad and auto companies were among the biggest decliners after Canadian government officials said there’s an increasing chance that U.S. President Donald Trump will give six months notice to withdraw from the Nafta trade agreement. The auto and freight sectors are considered to be the most “at risk” in the Nafta renegotiation talks as movement of manufacturing facilities and lower trade volume could hurt financial results and decrease productivity. Kansas City Southern fell as much as 4.6 percent after the report, its biggest loss in more than eight months. Peer Canadian Pacific Railway Ltd sank 3.3 percent in Toronto and CSX Corp. slipped 1.7 percent. General Motors Co. slid as much as 3.3 percent while auto-parts stocks also fell, paced by Lear Corp. down as much as 3.8 percent and Magna International Inc. down 4.9 percent. A White House official later said there was no change to Trump’s position on Nafta.