The consulting firm says Canadian vehicle sales for August totalled 183,900, including 59,096 cars and 124,849 light trucks.
August is the fourth record-setting month in a row, and seventh for the year, with only April falling short of setting a new high.
General Motors was the leading car brand in Canada last month for the first time since before its 2009 bankruptcy.
The U.S.-based company sold 28,981 vehicles last month, a 28.5 per cent increase from a year ago.
Fiat Chrysler sold 19,648 vehicles in August, down 9.2 per cent, while Toyota was up 7.7 per cent to 17,950. Volkswagen sales were up 71.9 per cent to 9,032.
Ford currently holds top spot for the year despite a 5.9 per cent drop in sales in August to 27,286 and 215,224 for the year.
DesRosiers says GM has a “long shot” at beating Ford for the year as sales were up 18 per cent to 205,329 in the first eight months of the year.