TORONTO – Canada’s main stock market posted its first daily gain in September on Tuesday, joining U.S. markets in a positive day of trading as investors await important news about trade and political decisions on both sides of the border.The 17th anniversary of the terrorist attacks in the United States was basically flat but marked the first TSX gain since Aug. 29, said Catharine Sterritt, portfolio manager for CIBC Asset Management.“It’s as if the market is just holding its breath because we are in front of a lot of news,” she said in an interview.Sterritt pointed to the prospect of important details coming out of Liberal caucus meetings in Saskatoon about the government’s response to the Trans Mountain judicial pipeline decision and the federal response to the U.S. competitive advance from its adoption of accelerated depreciation.Markets are awaiting the conclusion of NAFTA negotiations in the coming weeks as well as China’s response to further potential trade tariffs imposed by the U.S.The S&P/TSX composite index closed up 37.16 points to 16,094.25, after reaching a high or 16,111.65 on 215.6 million shares traded. The market recovered some of the losses over the past seven trading sessions but was still down 1.8 per cent from when it began to lose ground.All sectors except for energy, utilities, gold and base metals rose on the day. It was led by health care even though many cannabis stocks were down.Canadian transportation companies including railways and airlines drove an increase for the industrials sector while the important financial, materials and energy sectors were essentially flat.Recreational products company BRP Inc. was the biggest loser of the day on the TSX after it launched a marketed secondary offering for 8.7 million shares by its largest shareholders and also filed to list its shares on the Nasdaq Global Select Market. It closed down $5.98, or 8.41 per cent, to $65.13.The Canadian dollar was trading at an average of 76.22 cents US compared with an average of 75.97 cents US on Monday.It rose as Foreign Minister Chrystia Freeland briefly resumed NAFTA negotiations in Washington.“The overall market is still expecting that we’re going to see a positive resolution, especially on the auto side, but it is concerning this threat of auto tariffs and so people do want to see this resolved,” Sterritt said.The October crude contract was up US$1.71 to US$69.25 per barrel as concern was raised about potential disruptions from hurricanes in the Gulf of Mexico. This comes despite expectations that the U.S. administration is putting pressure on OPEC and Russia to keep oil flowing to reduce prices at the pump ahead of key midterm elections, she added.In New York, the Dow Jones industrial average was up 113.99 points to 25,971.06. The S&P 500 index was up 10.76 points to 2,887.89, while the Nasdaq composite was up 48.31 points at 7,972.47.The risks overhang a booming core economy in the United States, where demand is growing and there is another industrial revolution happening in technology that could spur further market growth.“It’s very interesting times when we have such strong corporate metrics and so many clouds on the macro horizon,” Sterritt said. “It’s going to be a stock pickers opportunity for sure.”The October natural gas contract was up 2.4 cents at US$2.83 per mmBTU.The December gold contract was up US$2.40 to US$1,202.20 an ounce and the December copper contract was down 0.65 cents at US$2.62 a pound.