Department director-general Sunai Manomai-udom said he would be undeterred by the prospect of the DSI announcement today infuriating pro-Thaksin protesters.

"All investigations by the DSI, be they the corruption charge concerning the Ban Ua Athorn project or Krung Thai Bank's alleged lending fraud, are conducted according to the evidence. No matter what the results, this has nothing to do with the protests. The protesters may not be interested in the DSI's investigation results, because these cases must still go through court proceedings," he said.

He also said the SC Asset case had no connection with the Constitution Tribunal's judgement that Thaksin committed an "honest mistake" years ago when he transferred shares to a maid and a chauffeur and did not include the shares in his assets report.

"This is a new case. In prosecution circles, an honest-mistake claim can be used once. The excuse cannot be used in a new case, because it is already known that such a practice is wrong," Sunai said.

The Securities and Exchange Commission has accused Thaksin of failing to inform the authorities of his shareholding in OAI Property, the old name of SC Asset. In filing his stake, Thaksin did not include the shares he transferred to Win Mark, saying that Win Mark was not his company.

However, the Democrat Party had earlier found that Win Mark had the same address as Ample Rich Investments - the company Thaksin admitted establishing in the British Virgin Islands to hold his 10-per-cent stake in Thai telecom holding company Shin Corp.

If convicted under the Securities and Exchange Act, Thaksin would be subject to up to five years' imprisonment and a fine no more than twice the value of the shares he offered to sell to related parties. The value of shares Thaksin sold in 2000 was Bt969 million, meaning he could be fined Bt1.938 billion.

In 2000, Thaksin said he had sold shares in three property companies - OAI Property, PT and SCK Asset - to Win Mark for a total of Bt906 million. However, the Democrats found that Win Mark also held shares in two other companies: SC Office Park and Worth Supplies. Total investment in the five firms was Bt1.5 billion.

In his 2000 statement, Thaksin said Win Mark had bought the shares on expectation of reaping profits when the firms were listed.

However, Win Mark had sold shares in OAI Property to Value Asset Fund of Malaysia (VAF) in 2003, and three weeks later VAF sold the shares to Overseas Globe Fund and Offshore Dynamic Fund Inc. The three funds share the same address in Malaysia. Remarkably, the sale took place before OAI Property, later renamed SC Asset, was about to list on the Stock Exchange of Thailand in November of that year.

VAF also transferred the right to buy 70 million new shares of OAI at their Bt10 par value to Thaksin's daughters, Pinthongta and Paetongtarn. Based on the initial public offering price of Bt15 per share, the two children automatically netted a total profit of Bt350 million.

Democrat Party deputy secretary-general Korn Chatikavanij earlier asked why, if it had no connection with the Shinawatras, the fund was willing to lose the potential profits it could have realised months later.

He also accused Thaksin of having set up Win Mark as a personal trust fund to hide profits from the baht's devaluation in 1997 and facilitate his family's share transactions. The Democrat said Win Mark could have been hiding profits from speculation on the baht.