THE Hang Seng Index could open with further gains today, as indicated by overnight buying of Hong Kong blue chips in London. At about 11.15 pm last night, the Fleming Hong Kong Index - an index which functions like the Hang Seng Index outside local trading hours - reached 9,804 points, up 68 points from yesterday's local record close of 9,736.57. In local trading yesterday, strong overseas buying pushed the index to a record close of 9,736.57 - up 126.88 points, or 1.32 per cent - on Monday's close. Within about 20 minutes of trading, the index achieved the day's high of 9,937.36 - just 63 points from the psychological 10,000 barrier. The previous closing high of 9,733.34 and all-time high of 9,825.5 were reached on November 15. Turnover was a heavy HK$9.76 billion yesterday, against HK$8.73 billion on Monday.