Hong Kong: More than $5 billion (Dh18.3 billion) was wiped off the market value of Sun Hung Kai Properties yesterday after the billionaire owners of Asia's largest real estate developer were arrested on suspicion of corruption.

Hong Kong's Independent Commission Against Corruption (ICAC) arrested Raymond and Thomas Kwok in the agency's biggest investigation since it was set up in 1974 to root out what was seen as widespread corruption in the government and police.

Rafael Hui, a former No 2 official in the government, was also arrested, according to media reports. Hui resigned as an independent director of insurer AIA Group late Thursday.

The arrests come just days after Hong Kong elected Beijing-loyalist Leung Chun-ying as its next leader, pledging land for cheaper public housing, and as soaring property prices, the most expensive in the world, have stirred public discontent. Home prices almost doubled in the five years to end-2011, according to real estate broker Knight Frank.

"This is not good for the image of Hong Kong, which used to have a high reputation for integrity," said Joseph Wong, a former senior government official and colleague of Hui.

"The impression is that government policies tend to favour the rich tycoons, particularly rich property developers. These sorts of cases will only add to the suspicions."

The two Kwok brothers and Hui were released late Thursday but were expected to return for more questioning, according to a source familiar with the matter. Local media reporters said the brothers were still inside a Deepwater Bay luxury compound on the south side of Hong Kong yesterday.

Net worth

The Kwoks are worth $18.3 billion, according to Forbes, the second-biggest family fortune in Hong Kong after Asia's richest man, Li Ka-shing, founder of rival developer Cheung Kong. Sun Hung Kai said the Kwoks would continue with their duties as chairmen and managing directors, and normal business operations would not be affected.