SANTA MONICA, Calif. -

TrueCar gave automakers and brands their monthly report cards late last week and one domestic OEM, in particular, moved close to the top of the class.

After earning a C+ in January, General Motors not only showed some of the highest month-over-month improvement but also tied with Hyundai with the second-highest grade of any manufacturer, earning an A for February. Porsche topped the list of OEMs with an A+.

Officials explained that TrueCar evaluates brands and OEMs in the following categories: pricing, sales, incentives, customer loyalty, market share and days in inventory.

Not only did GM enjoy a strong spot in the OEM rankings, it also enjoyed some success in the brand rankings as well. Each was given A or A+ grades, including Buick, which took an A+ and was tied with Porsche and Smart for the lead among all brands.

“All four of the GM brands received a grade of A or A+, which points to the remarkable improvements the company has shown recently in areas that make up the bulk of our scoring, such as increases in retail sales and lower discounts,” explained Jesse Toprak, TrueCar’s vice president of industry trends and insights.

“Hyundai also gets an A for their continued sales gains fueled by their lineup of vehicles that organically fit consumers’ value-oriented product preferences,” he added.

Conversely, the OEM with the lowest grade was Saab, which had a D. It was followed by Daimler (D+). Mitsubishi and Ford tied for third-lowest (C-). Among brands, Chrysler, Honda and Mercedes-Benz tied for the lowest grades, as each was given a D.

Joining GM in the OEMs showing the most upward month-over-month movement were Nissan — which improved to a B+ after getting a C- in January — and Mazda, which improved its D to a B-.

Meanwhile, the manufacturers with the heftiest drops were Daimler, which got a D+ following an A- in January; Subaru, which took a B- after earning an A in January; and BMW, whose B+ slipped to a C+.