CHINESE carmaker BYD’s profit warning and failure to deliver its promised electric car sent shares to a more than two-year low, as the Warren Buffett-backed company struggles with sales declines. Shares in BYD fell more than 14 per cent yesterday after the company warned it may post a third-quarter loss. The drop put a spotlight on Buffett, whose investment in BYD has lost around $2bn in value since he took a stake in 2009.