In addition to investing in stocks, real estate and antiques, Chinese billionaires are discovering a new source of big returns - the wine market. The yield rate from some famous French vintages during the first half of this year has exceeded 30 percent, far above any alternative.The price of historic and exclusive Chateau Lafite Rothschild, from Bordeaux in France and the most popular wine brand in China, is rising monthly. In July, one bottle of the 2007 vintage cost 4,500 yuan (US670). It jumped to 5,000 yuan in August and is expected to exceed 6,000 yuan with the Mid-Autumn Festival and National Day holiday around the corner.