Raymond Kwok has hired British firm Reed Smith Richards Butler. His elder brother Thomas has retained London-headquartered Clifford Chance and Hong Kong-based Boase Cohen & Collins.

A third brother, Walter Kwok Ping-sheung, the eldest who was forced out of the property developer in a bitter family feud, subsequently was arrested and is out on bail.

The case is one of the highest-level corruption investigations in the city's history.

Legal experts said that, in theory, using separate lawyers could indicate the brothers are preparing for the event that they are put in an awkward position against each other in court.

'A sharp fall in the share price will be unlikely. As some funds may be restricted from investing in companies with top management embroiled in legal disputes, it will be negative to the company's share performance in the short term,' said Eric Yuen Chi-fung, the head of research at Guoco Capital.

SHKP requested its shares be suspended from trading at 9.48 am yesterday, pending the release of the ICAC announcement. The shares edged up 0.052 per cent to HK$95.45 before the halt in trading.

The company's share price has fallen 14 per cent since the arrests of March 29, compared with a 3.1 per cent decline in the Hang Seng Property Index.

Trading in two subsidiaries of SHKP - SmarTone Telecommunications Holdings, a mobile phone operator, and Sunevision Holdings, an information technology firm - were also suspended yesterday, according to the Hong Kong stock exchange.

The growing uncertainties might send the shares as low as HK$86, Yuen said.

While critics suggested the Kwok brothers should step down, a lawyer who asked not to be named said: 'There is no legal requirement for listed company chairmen or board directors to resign until they are found guilty.'

But legislator Chim Pui-chung argued that it would be better for the firm's reputation if the joint chairmen were suspended from their duties for the moment.

'They should step down now and come back when all the charges have been cleared,' he said.

Retail investors have remained upbeat about the stock, at least for the time being.

'Its share price has climbed back to HK$95.45, from about HK$87 last month,' said 65-year-old Cheng Sum, a retired housewife. 'I'm confident that it will later rebound back to more than HK$110,' said the investor, who bought nearly 10,000 shares of SHKP at an average price of around HK$65 per share.

News of the high-profile arrests initially sank SHKP's share price. It has since stabilised but is still down about 14 per cent compared with before news of the arrests broke.

The brothers' arrests also created a stir in legal circles, where big lawsuits can mean paydays of tens or even hundreds of millions of dollars in legal fees.

'After Tony Chan's case, this is going to be another textbook case for all lawyers in Hong Kong to monitor and study,' said a partner at a local law firm who is not involved in the case, referring to the battle over the estate of late Chinachem chairwoman Nina Wang Kung Yu-sum.

In February, the Court of Appeal dismissed fung shui adviser Tony Chan Chun-chuen's attempt to overturn a ruling that denied his claim to Wang's multibillion-dollar fortune. The case attracted a lot of attention as it dragged on for more than five years. Chan now faces a HK$150 million bill for legal fees for his failed lawsuit, including the court costs that were incurred by the winning side.

Local lawyers with major firms charge clients between HK$2,000 and HK$5,000 an hour, depending on the lawyer's experience and qualifications as well as the complexity of the case. Senior lawyers sometimes charge more than HK$10,000 an hour.

Although SHKP has repeatedly assured its shareholders and clients that it is business as usual, investors worry what will happen to the company, one of the largest listed property developers, now the two Kwoks have been formally charged.

Some shareholders had already been pressing the company to make a Plan B for management control, in particular for day-to-day operations, since the two Kwoks will now have to spend a lot of their time dealing with the lawsuit.

'A case like this could go on for five years or even seven or eight years,' said an analyst at a major investment bank who monitors the case closely for her clients.

'People like the Kwok brothers will appeal [if they lose] again and again and that, of course, means more money for their lawyers.'