Thai shares plunged 3.6% at one point yesterday, their biggest intraday percentage drop since August 2015, on growing anxiety over domestic factors.
The SET index, bucking the trend in Asian markets and certainly the biggest loser in the region, went into free fall shortly after the opening bell, sliding 53.47 points to 1,450.87 before closing at 1,457.02 for a 3.2% drop in brisk trade worth 74.14 billion baht.
Big-cap stocks were under heavy selling pressure. Coal miner Banpu Plc (BANPU) fell by one baht to 16.50, CP All (CPALL) dipped 2.50 baht to 61.50, Kasikornbank (KBANK) dived 6.50 baht to 185.50, Siam Commercial Bank (SCB) skidded six baht to 145, and PTT Plc (PTT) tumbled 10 baht to 335.
Institutional investors yesterday yanked out 7.27 billion baht from the stock market, while retail investors bought a net 6.9 billion baht and foreign investors snapped up 998.7 million baht more than they sold. Brokers were net sellers of 627.33 million baht.
The main Thai bourse has been on a wild ride in recent months, losing nearly 6% since the end of August and paring the year's gain to 13%.
The baht fell to a two-month low of 35.08 against the dollar by mid-morning yesterday, before rebounding slightly to 35.06 in late trade, marking a sixth straight day of losses.
Kasikorn Securities managing director Padermpob Songkroh said concerns over both global and local factors took a toll on Thai shares.
The SET's price-to-earnings ratio during the past 10 years was 10-15, compared with its forward P/E of 14-15, so the market is sensitive to any negative factors at the moment, he said.
The broker forecasts the SET index to move in a band of 1,335-1,540 over the next 12 months, representing 6% to the upside or 8% to the downside.
"Whatever factors affect the market, the strong support of 1,335 points is the entry level for investors because the market at that level is trading lower than fair value," Mr Padermpob said.
Kasikorn Securities recommends accumulative buying in insurance, banking and commodity-related stocks.
Chaiyot Jiwangkul, head of research at Globlex Securities, said domestic concerns are weighing on market sentiment, while worries about the US Federal Reserve's rate hike prospects have also hit the market -- though the latter problem is largely priced in.
After yesterday's sharp fall, a technical rebound could emerge, Mr Chaiyot said. He tipped support at 1,450 and a next level at 1,410.
In the meantime, Kanate Wangpaichitr, president of the Federation of Thai Capital Market Organisations (Fetco), said investor confidence about the three months to December declined to neutral territory from a bullish reading in the previous survey.
Fetco's investor confidence index in October fell to 103.84, down from the previous month's 140.68.
A figure below 80 points is bearish, 80-120 is neutral and 120 or more is bullish.
The confidence index for all investor groups fell or stayed neutral, with the mood among foreign investors declining the most.
Construction services was the most attractive sector, media and publishing the least attractive.