SUN Hung Kai Properties' (SHKP) last-minute decision to sell additional flats at Villa Athena has calmed speculative activity at the Ma On Shan residential development. Speculators had been expecting quick profits from the sale, but the release of four more blocks dampened their hopes. With more flats on offer, property agents said speculators who had won the right to buy flats at Villa Athena had found it more difficult to ask for a big premium on the flat price. Peter Wong, sales manager at the Sha Tin branch of Centaline Property Agency, said activity in the ''grey market'' had been slower than expected because of the additional supply. ''With an extra supply, home buyers now have a bigger chance to get a flat. The premium asked by speculators has been cut substantially,'' he said. Property agents said some buyers had earlier offered to pay speculators an extra $300,000 or more for flats at Villa Athena. Now, with more flats on sale, buyers were expecting to pay less. Sun Hung Kai decided to release four more blocks with a total of 394 flats after about 5,000 people registered for the initial 100 units. Prices of the extra units were up to four per cent higher than the initial $4,457 a square foot. Leung Chi-man, head of the Sha Tin branch of Midland Realty, expected more than 90 per cent of the 494 units would be sold today, the first day for buyers to choose flats. He estimated that about 30 per cent of the people registered for the sale were speculators.