In its research note, Asia Plus Securities said that Ch Karnchang may also share the same fate. They are likely to be replaced by MK Restaurants and Kiatnakin Bank when the Stock Exchange of Thailand announces the new list for the calculation in the July-December round.
Kim Eng Securities (Thailand) noted that THAI tends to show a bigger loss than expected this year.
At an analysts meeting last week, THAI estimated that it would show Bt3.5 billion loss in the first quarter.
However, Kim Eng said the actual loss could be 20 per cent higher. The airline will face the low season in the second quarter, while political conflicts would dent travelling demand among Asian travellers who account for 51 per cent of the company's revenue.
Meanwhile, analysts were told that THAI plans to decommission two more aircraft, to bring the total to 15 this year. It also announced a cut in the investment budget by 28 per cent to Bt18 billion and the layoff of some 2,000-3,000 employees in the next three years.
At 2.20pm, THAI share price was unchanged at Bt13.10, continually sliding from the 1-year peak of Bt33.75 on May 31 last year.
The SET 50 index is calculated from the stock prices of the top 50 listed companies in terms of market capitalisation, high liquidity and compliance with requirements regarding the distribution of shares to minor shareholders.