The beleaguered Securities and Exchange Commission yesterday issued a rebuttal to the Democrat Party's accusation that it had whitewashed Prime Minister Thaksin Shinawatra's family members on charges concerning the Shin Corp sell-off.

"The comment that the SEC puts the family's interests before the national interest is unfair to the agency," SEC secretary-general Thirachai Phuvanat-naranubala said in a statement.

"Concerning the report that [MP] Korn Chatikavanij will launch a legal case against the SEC, I realise the risks. However, at the same time, failing to ensure fairness to those involved and abuse of power could also draw legal cases against the SEC from those investigated. The SEC therefore needs to be fair and uphold the same [regulatory] framework that we have enforced on others," he said.

Thirachai urged anyone with evidence showing a contradictory conclusion from the SEC's to come forward.

The SEC's press conference on Thursday provoked dissatisfaction from Democrat MPs investigating the alleged irregularities behind the Shin stock sale, particularly those concerning individuals and brokers-custodians in the deal.

Korn said yesterday that the party's fact-finding team would likely submit its list of dubious points to the SEC on Monday.

One such grey area is the report by UBS Singapore Branch to the SEC upon receiving 10 million Shin shares from Ample Rich Investments Ltd on August 24, 2001. UBS stated that it had bought the shares at Bt179 apiece.

The SEC's explanation was that UBS did not understand Thai laws. The bank claimed ownership of the shares in the filing and the price could have been the average trading price of Shin on that day.

Korn said UBS in fact did not need to make any filing under trading rules, as the stake that it had bought represented less than 5 per cent of Shin's capital, the threshold that triggers a mandatory filing.

"It filed the report and specified the purchase price because it combined the 10 million shares with 5 million Shin shares already under its care. The combined number of shares exceeded 5 per cent, which prompted it to file the report," he said.

Although UBS could have several accounts holding Shin shares, the bank specifically combined the 10 million shares with the 5 million shares in the account of a particular client, he added.

"We can assume that UBS knew that Ample Rich and the particular client are identical. It thus combined the number of shares and filed the report. Despite this, the SEC opted to accept that it had filed a wrong report," Korn said.

In the SEC's statement, Thirachai insisted that the SEC's examination was within its legal framework and based on evidence that could be cross-checked. He said he could not be swayed by an individual's belief in any investigation, regardless of the investigated person's social and political standing.

If the public still harboured doubts about the UBS case, the SEC would ask the Monetary Authority of Singapore to check with the Singaporean bank to ensure that its clarification was sufficient.

The SEC has become the latest government agency to come under fire, following the Revenue Department, which received nothing from the complex deal that allowed the Shinawatra and Damapong families to net Bt73.3 billion tax-free.

Next week, the Commerce Ministry and the Stock Exchange of Thailand (SET) - both of which launched investigations under mounting public pressure - will come under the spotlight.

The Commerce Ministry is expected to disclose the results of its probe of companies believed to operate as nominees for the parties to the deal.

According to a SET source, the exchange will also announce if any executives of the Shin group - including the outgoing president of Advanced Info Service Plc, Yingluck Shinawatra - had used inside information for personal gain.