The Stock Exchange of Thailand Index slid 0.97 points from Thursday to close at 1,360.50, a decrease of 0.8% from the previous Friday's close of 1,372.18. Turnover was 32.8 billion baht, with 4.4 billion shares traded.
The decision by the Constitution Court to void the results of the Feb 2 election appeared to be largely expected by investors in a market that us still up 4.8% from the end of 2013 despite protracted political turmoil.
The Bank of Thailand on Friday cut its growth forecast for this year to 2.7% from its earlier prediction of 3%, based on the assumption that political tensions will ease by mid-year. However, the growth rate may be lower should the unrest stretch into the second half, it said.
Foreign investors were net sellers on Friday of 335.6 million baht worth of Thai shares, but have been net buyers for the month to date of 5.11 billion baht. For the year to date they are net sellers of 29.9 billion baht.
Local institutions were net sellers of 448.78 million baht and brokers sold 101.59 million. Individual investors were net buyers of 886 million baht.
Asian markets rose on Friday as bargain-hunters moved in after the previous session's heavy losses, with investors taking a lead from Wall Street and positive US data.
Sydney climbed 0.83% to 5,338.1 and Seoul gained 0.80% to close at 1,934.94 while Shanghai surged 2.72% to 2,047.62 after big losses on Thursday in response to the Fed news. Hong Kong jumped 1.2% to 21,436.70. Tokyo was closed for a public holiday.
Global markets skidded after Janet Yellen told a news conference that a rate rise could come "around six months" after the bank's stimulus programme ends. Economists took that to mean sometime the first half of 2015.
However, US shares enjoyed a bounce on Thursday from upbeat data including lower unemployment claim figures.
In Bangkok, the SET50 index of blue chips ended at 919.32 points, down 0.90, with total trade value of 24.25 billion baht. The SETHD index of high-dividend shares slid 1.22 points to 1,098.91, with turnover of 10.32 billion baht. The Market for Alternative Investment lost 2.42 points to 404.10, with transaction value of 884.95 million baht.
In the currency markets,the baht had its first weekly drop this month and bonds declined after the Fed signalled that interest rate increase may come sooner than expected.
The baht had touched a three-month high on Wednesday, a day after the cabinet ended the largely ineffective state of emergency it imposed on 22.
"We have a mixed picture for the baht," said Paisarn Lertkowit, a currency trader at Bangkok Bank. "The Fed comments should be dollar-positive, but there was some easing concern among offshore investors about Thai politics that led to some baht demand."
The baht was trading late Friday in Bangkok at 32.39 to the dollar, compared with 32.40/42 on Thursday and 32.30/33 a week earlier.
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