The SET's senior vice president Sethaput Suthiwart-Narueput said research into factors impacting upon the debut performances of IPO shares found that the issues were always concentrated in the fourth quarter, which creates conditions of oversupply.

"From that fact, we found that about three times the number of IPO shares are sold in the fourth quarter than in the remaining quarters. Because the IPO share sales are concentrated in the fourth quarter, they suffer 20-per-cent-lower returns than those offered in other quarters," he said.

Between 2002 and 2005, about Bt140 billion was raised from IPOs in Thailand, but demand - based on the number of active stock trading accounts - did not increase significantly.

"If we can increase the number of active accounts by 10 per cent, it will be the main engine in raising IPO returns by 10 per cent, or Bt4.7 billion," Sethaput said. "Therefore, it is necessary to solve the problem of their concentration at one time of the year, coupled with expanding the investors' base."

In 2005, 35 stocks began trading on the stock market, but as many as 13 of them had disappointing debuts. Of the 35 new stocks, 16 were launched on the stock market in the fourth quarter, 10 in the first quarter, 5 in the second and the remaining four in the third.

Two stocks - G Steel Plc and City Steel Plc - had their debut on the stock market earlier this year and both performed poorly on the first day of trading.

Sethaput said the accumulation of IPO share sales at certain times of the year between 2003 and 2005 could be ascribed to the SET's time-consuming and tightened scrutiny process.

Meanwhile, Tira Thai Plc, which issued this year's third initial public offering, has announced that its 30-million IPO shares were sold out in the first day of subscription.

The company, a power transformer manufacturer and distributor, sold its newly issued shares at Bt5.75 each. Eighty per cent of them were subscribed by retail investors and the remainder by institutional investors.

The stock will start trading on the Market for Alternative Investment on May 10.

KGI Securities (Thailand) is financial adviser for the Tira Thai offering. KGI's ssistant vice president Patchaporn Sankaburanurak said Tira Thai's major clients included Egat, the Provincial Electricity Authority, the Metropolitan Electricity Authority, Banpu and PTT. All have shown continuing growth in earnings and this will drive Tira Thai's earnings, he said.