BEIJING - Even though many treat wine merely as another must-have luxury, wealthy Chinese are already making a splash in the wine futures market.Chinese buyers are the main force causing the French fine wine index to shoot up 37 per cent from one year ago and 24 per cent this year, Shanghai-based independent economist Andy Xie wrote recently in Caing business magazine.Bordeaux's top 200 or 300 wineries run a presale system called sale en primeur. Early each summer, they exchange futures contracts with middlemen who then do deals with collectors, investors and retailers.