Demand for the Buick Envision crossover SUV continued to be high. Buick's sales in China were up big in January. Image source: General Motors.

General Motors (GM 2.60%) said that its sales in China rose 7.3% in January, helped by strong demand for key Buick and Cadillac products.

Given that we know China's new-car market has been slumping recently, that sounds pretty good, doesn't it? Hang on.

Chinese New Year complicates year-over-year comparisons
Here's the thing about those results: The year-over-year comparison is a little tricky.

China has a big holiday, Lunar New Year, that sometimes falls in late January and sometimes in early February. Many businesses in China (including, for instance, car dealers) close for several days around the New Year celebration. 

Last year, the Chinese New Year's celebration fell in January. This year, it was in early February. See the problem?

GM managed a 7.3% year-over-year gain, but last year's results may have been dented by the holiday. Consider that rival Ford (F 5.72%) managed a 36% sales increase in China in January, Toyota (TM 0.86%) saw sales jump 32%, and Honda's China sales were up almost 21%. 

In that context, GM's gain for January doesn't look so hot. What happened?

Good results for Buick and Cadillac, less so at Chevrolet
What happened is that a fuel-economy subsidy that had helped boost sales of a key Chevrolet model came to an end at the end of 2015, and that put a big dent in the brand's year-over-year results.

The model in question is the Chevrolet Sail, a small sedan developed in China as an entry-level model. The Sail has been quite popular, thanks to a government subsidy that made it even more affordable. But that subsidy ended -- and Chevrolet sales in China fell 27% in January, to 56,133 vehicles. 

The Chevrolet Sail. Image source: General Motors.

Results for GM's other brands were more encouraging. Buick sales rose 39% to 138,907, thanks in part to continued high demand for the compact Buick Envision SUV. The Envision has been a big seller since it was first launched in China a little over a year ago, winning praises for its ride quality and fit and finish. 

Sales of GM's affordable Baojun brand jumped 101% from a year ago, thanks to the ongoing success of another hot GM SUV, the Baojun 560. Baojun sales totaled 78,367 units in January. 

Last but not least, sales of Cadillacs in China rose 16% in January. The sales totals are still tiny -- Cadillac sold just 8,337 units in China last month -- but GM's long-term plan to establish Cadillac as a significant player in China's luxury-car market is slowly gathering steam.

What's next for GM in China
While several key competitors posted gains for January that were far ahead of the General's, in fairness it's hard to divine a trend from GM's January numbers because of the difficult year-over-year comparison. 

After GM reports February's results next month, we'll combine the two months' results to come up with better year-over-year comparisons, and better comparisons with rivals' results. Stay tuned.