SANTA MONICA, Calif. -

In TrueCar.com’s January Performance Scorecards that ranked manufacturers and brands across a wide spectrum of criteria, there was one automaker, in particular, that was the head of the class.

Not only did Porsche show the most month-over-month improvement for any OEM, but it also was the top scoring manufacturer and tied for the lead among individual brands.

Looking first at the manufacturer list, Porsche received an A+ to come in at No. 1 and was followed by Subaru (A), Jaguar Land Rover (A) and Daimler (A-). By individual brands, Porsche tied with Buick and Subaru for the lead, as all earned A+ grades.

TrueCar evaluates brands and OEMs by the following eight metrics: pricing, sales, customer loyalty, market share and days in inventory.

In contrast to the high marks of Porsche and others, the OEMs with the lowest grades were Saab (F), Mazda (D) and then Nissan and Honda tying for third from the bottom as each was given a C-.

Meanwhile, Mercury was the lone brand that was given an F, putting it at the bottom of the brands list. Mercury was, of course, recently cut from the Ford lineup. Saab and Honda each received D- grades and followed Mercury. Saab has been low on inventory with the brand recently gaining a new parent company.

The OEMs to show the strongest sequential gains were Porsche, which was up to an A+ from a C+; Mitsubishi, as it improved its grade to a C+ after earning a D+ in December; and Volvo, whose C in January bested the D from the month before.

Conversely, the automakers who had the heftiest declines were General Motors, which saw its score drop to a C+ from a B+; Chrysler, whose B fell to a C; and Mazda, whose C dropped to a D.

“Most luxury brands outperformed the industry average in January as recovering consumer demand improved their performance scores more dramatically than popular nameplates,” stated Jesse Toprak, TrueCar’s vice president of industry trends and insight.

“Buick’s performance was noteworthy due to improved retail sales and market share while maintaining low discounts,” Toprak added.