BULL buying after strong profit taking in the morning session saw Hang Seng Index cash and futures make gains. May futures rose 190 points to 9,425, a premium over the cash of 35 points, on 23,200 contracts. June rose 210 points, in strong buying during the afternoon, taking the contract to 9,475, a premium over the cash of 85 points. Open interest for Wednesday in May futures was 26,198 contracts and in June 20,526 contracts. The high of the day in the contract was 9,490. In index options, Jardine Fleming said investors were bullish about the coming months, with special interest in buying June 9,400 calls and selling June out-of-the-money puts. 'Those expecting the market to peak at 9,800 sold June 9,800 calls,' Jardine Fleming said. Front-month implied volatility lifted to 27.5 per cent. An indication that a full-blown bull rally is in place would be for implied volatility to rise above 29 per cent for an extended period. The volume of trading in options was 3,526 lots with open interest for Wednesday at 40,000 lots. In May there were 9,892 calls and 9,150 puts. In June there were 6,538 calls and 10,507 puts and in September there were 1,855 calls and 1,833 puts.