in inventory at the end of November, plans to idle the Lordstown, Ohio, plant where the car is built for two weeks in December instead of the planned one week to reduce supplies, said two people with knowledge of the plans who asked not to be identified. A spokesman did not confirm the plans.
Ford's shares closed down 0.3 percent at $11.41, while GM shares fell 1.4 percent to $25.51 on the New York Stock Exchange on Monday.
Ford said it planned to build 750,000 vehicles in North America in the first quarter of 2013, which would be an 11 percent increase from 2012. That would be the highest first-quarter production level since 2006.
GM's sales rose 3 percent to 186,505 cars and trucks, below the expectations of several analysts. The company said the average price paid per vehicle rose $750 from last year.
TrueCar estimated that the industry's average vehicle selling price in November rose 1.1 percent, or $335, from last year, and rose a similar amount from October to $30,832.
Chrysler, majority-owned by Fiat SpA, said sales rose 14 percent to 122,565 cars and trucks, its strongest result since 2007.
Toyota's sales rose more than 17 percent to 161,695 vehicles. Honda and Nissan both reported better-than-expected results, with the former jumping about 39 percent and the latter increasing 13 percent.
Hyundai said sales increased 8 percent to the company's all-time high for the month. November marked the first sales results since the South Korean automaker and its Kia Motors Corp affiliate announced they had overstated the fuel economy ratings by at least a mile per gallon on more than 1 million recently sold vehicles.
In the battle for the luxury sales title for the U.S. market, Daimler's Mercedes brand leads last year's winner, BMW, by fewer than 2,000 vehicles with one month to go.