General Motors Co. says its joint ventures in China combined for an all-time monthly sales record in September, delivering 181,148 vehicles.

The performance made China GM’s biggest market in September, surpassing the auto maker’s U.S. volume of 155,711.

Sales rose 55.6% to 1,292,549 units through the first nine months, giving GM China an estimated market share of 13.4%. The U.S. remains GM’s biggest market year-to-date, with 1,537,294 deliveries.

The Shanghai General Motors Co. Ltd. joint venture sold 71,566 vehicles in September, also a monthly record. Year-to-date deliveries are up 40.4% to 480,202.

Much of the sales boom reflects a range of new products and influx of first-time buyers in some of China’s biggest cities, Kevin Wale, GM China group vice president and managing director, says in a statement.

“In the compact sector, the new (locally built) Chevrolet Cruze sold more than 48,000 units in just six months,” Wale says.

The new Buick Regal sold 63,954 units since it was launched in December, and demand for the new Buick LaCrosse continues strong in the upper-medium sector, with 19,400 units delivered in its first three months on the market, he adds.

At the SAIC-GM-Wuling mini-commercial vehicle JV, sales broke the 100,000-unit barrier for the second time, with 100,635 vehicles in September. Deliveries are up 64.5% year-to-date, totaling 801,869.

In its first full month of operations in September, the newly formed FAW-GM Light Duty Commercial Vehicle Co. Ltd. JV sold 8,780 light-duty trucks and vans. The new JV began operating in August.