A total of 905 companies had released their half-year profit forecasts as of Tuesday, with 495 companies reporting a profit growth or loss reduction, according to data provider Great Wisdom.

Shenzhen-based automaker BYD ranked first in the list with up to 2,973 percent growth expected in its half-year profit.

The company said that increased auto sales, rising profits from its cellphone parts and phone assembly business and the rising prices of solar products were all behind the surge.

Though the company listed increasing auto sales as the top reason, experts said that growth in its auto business alone would not account for such a huge rise.

"BYD is a mid-range brand among China's homegrown auto brands. It may report sales a little bit higher than the market average, but this is far from enough to back high growth of nearly 3,000 percent," Su Hui, deputy director of the auto market division at the China Automobile Dealers Association, told the Global Times Tuesday.

In the first four months, BYD sold 153,300 cars in the Chinese mainland, up 24.54 percent year-on-year, according to the China Association of Automobile Manufacturers.

"It is likely that the company has secured a big order in the cellphone business," Yan Xiaojia, an industry analyst with Analysys International, told the Global Times Tuesday.

The Shenzhen-listed company has been an original equipment manufacturer (OEM) for other handset brands for several years, and also produces cellphone batteries.

Media reports said that the company may even generate more profits from its battery business than from car sales. In March, it was reported that BYD may have secured a tablet PC OEM order from Hewlett-Packard.

A list from Apple Inc released last year revealed that BYD is also a supplier for the popular handset maker.

"Though BYD seems to generate very enticing profits from the OEM business, it is also facing increasing challenges in that regard — labor costs in Shenzhen has risen significantly in recently years," said Yan.

Though the company seems to have a wide business scope, the company did not cut back on its efforts in auto research and development. "BYD rolled out the most new models during the April Shanghai Auto Show compared with domestic competitors," Su noted.

Among the firms that expected to turn losses into gains,  Dalian Insulator Group Co has so far got the largest profit to loss ratio with up to 4,811 percent profit growth expected in the first half, followed by up to 3,640 percent profit growth expected of Petrochina Jinhong Energy Investment Co.