HANG Seng Index futures saw a weak rally yesterday, taking the May contract up 95 points to 8,485 in modest turnover. Trading in the futures was 15,213 contracts, against 235 in June. The June contract rose 75 points to 8,475. Trading on the day was characterised by a weak bearish opening at around the low of 8,280. Strong Hong Kong retail support in the morning coupled with local institutional activity in the afternoon to take the futures on a bumpy ride, ending the day with a minor rally. The mini-rally started at 3.15 pm around 8,370 and finished 115 points higher 15 minutes after the cash market closed. The cash market was at 8,412 at the close, up 43 points. Implied volatility in index options lifted in the front month to around 36.5 per cent, its highest since around April 13. The 100-day Hang Seng Index historic volatility was at around 39 per cent. Jardine Fleming said investors bought 8,400 June puts and those with a little more faith in the market bought May 9,400 calls. Option volume was relatively active at 2,799 lots. The open interest is at 28,138. The open interest in May futures is 33,164 and in June it is 443 contracts.