Thai share prices closed 0.26 percent lower Wednesday amid concerns over a stronger baht and doubts about economic growth, dealers said.
They said the market was also under pressure as investors remained jittery over soaring global oil prices, sparked by Iran's announcement of a major breakthrough in its nuclear programme.
The Stock Exchange of Thailand (SET) composite index fell 1.97 points to 755.43, and the blue chip SET 50 index lost 2.57 points to 525.23.
Losers slightly outnumbered gainers 151 to 150, with 134 stocks unchanged on turnover of 2.2 billion shares worth 16.3 billion baht (428 million dollars).
"The baht is strengthening too much. People are worried that it might decrease our competitiveness in the region," said Sukhbir Khanijoh, vice president and analyst at Trinity Securities.