HONG KONG - Chinese car maker BYD Co Ltd, backed by US billionaire Warren Buffett, said on Thursday that it sold 40,100 cars in April, down 11 percent year-on-year according to data from analysts.

April sales were up slightly from March's 40,027 units.

BYD, which makes batteries and some of the country's cheapest cars, did not provide a year-earlier comparison figure but analysts said it sold 45,110 in April last year.

Related readings:  BYD says to restart construction of Xi'an plants  BYD upbeat over 2011 after dismal 4th quarter  BYD to inaugurate electric buses in Denmark

Analyst said BYD had seen car sales fall on a year-on-year basis since August, largely as a result of over-expansion and an aggressive sales strategy.

"At this run rate, the company is probably not very profitable," said Yuanta Research analyst Johnny Wong.

But selling pressure on the stock was likely to be limited since the stock had fallen a lot, he said.

"A positive sign is that it seems sales have stabilised at around 40,000 units," said an analyst who declined to be named.

Shares of BYD rose 2.2 percent in late morning trade on Thursday, beating a 0.2 percent decline by the Hang Seng Index. The stock has lost about half of its market value since August.

Beijing's decision to scrap tax incentives on small cars at the beginning of this year had affected sales in that segment in the world largest auto market, analysts said.

They forecast subdued growth in the domestic car market this year after sales surged by a third to a record high in 2010.