Sino Land said it sold 39 of the first batch of 61 flats at its luxury One Mayfair development in Kowloon Tong within four hours yesterday. The average price was more than HK$18,000 per sq ft, with one flat fetching HK$20,808 per sq ft. Mainlanders accounted for a fifth of the buyers, said a spokeswoman for Sino Land. An analyst who did not want to be named said: 'The performance is positive as such pricey properties are less likely to sell as fast as mid-priced units.' But Adrian Ngan Wai-hung, head of property research at MF Global Hong Kong, was less upbeat. 'They sold slower than I expected. It indicates developers face challenges in selling expensive flats in a credit-tightening environment,' said Ngan, adding that he expected 80 to 90 per cent of flats to have sold. The flats start at 1,591 sq ft. The largest is 2,436 sq ft and has a garden. They range in price from HK$15,686 per sq ft to HK$29,380 per sq ft, or between HK$21.2 million and HK$71.56 million. According to data from Centaline Property Agency, 49.7 per cent of new flats, each worth HK$12 million or above, were sold to individual mainlanders in the third quarter, compared with 41.2 per cent in the second quarter and 34.9 per cent in the first. Apparently unscathed by credit tightening at home and in Hong Kong, mainlanders - not including those who bought through companies - accounted for 55.6 per cent of total transaction value. Wong Leung-sing, head of Centaline's research department, said mainlanders set a record in terms of both transaction volume and value. Meanwhile, Cheung Kong (Holdings) said it had made HK$30 billion in revenue from the sale of 3,600 flats and was confident it would exceed last year's HK$32 billion revenue.