比亚迪的股价还有多少空间?

BYD is a stock engineered to outperform: it's Chinese, it's green, and Warren Buffett loves it. Last year the Shenzhen-based battery-maker turned automaker, whose Hong Kong shares are 28 per cent-owned by the Sage of Omaha, delivered a 439 per cent return – the best of all 40 members of the Hang Seng China Enterprises Index.

There is substance behind that performance. Full-year figures, released after the market close on Friday, showed that auto sales were up 127 per cent, as BYD's cheap gas-powered F3 compact – a Toyota Corolla clone – lured price-conscious first-time buyers in second- and third-tier cities. This month's agreement with Daimler to develop a new electric vehicle for sale in China, meanwhile, is a genuine landmark: the first time that a Chinese company has offered proprietary technology into a Sino-foreign joint venture, rather than just land, buildings or manpower.

Yet a HK$157bn ($20bn) market capitalisation, just shy of 10 times book value, looks increasingly incongruous. Yes, Beijing is big on clean energy. But BYD, a private company, was naturally not on a list of eight state-appointed “industry consolidators” last year. Even on the most optimistic of forecasts, the contribution of electric vehicles to sales volumes will be negligible for years. Ditto exports of gas vehicles, which accounted for less than 3 per cent of unit sales last year. In BYD's home market, the gradual removal of stimulus-related subsidies and tax breaks is having a damping effect, especially for smaller models. Total auto sales were down 27 per cent between January and February.

Having delivered a return nine times better than the global auto sector in 2009, BYD has merely kept pace so far this year. Wang Chuanfu, the chairman who went rocketing 103 places up to the top of China's rich list six months ago, should enjoy the view while he can.