The Stock Exchange of Thailand index and other Southeast Asian stock markets fell on Thursday, in line with broader Asia on worries that mounting Sino-US trade tensions are hurting global economic growth.
The SET index declined 19.12 points or 1.18% to end at 1,599.54, in trade worth 56.97 billion baht. Thai shares dropped to their lowest close since August 2017 after the Finance Ministry said annual economic growth would slow in the April-June period.
Siam Commercial Bank Plc was among losers, down 5.50 baht or 4.47% to 117.50 baht, and True Corporation Plc plunged 40 satang or 7.02% to 5.30 baht.
Indonesian shares slumped 2.1% to their lowest close since mid-May 2017, extending their decline into a third session and making them the region's top losers.
Losses were broad-based with financial and material stocks leading the decline. Bank Central Asia ended 1.9% lower, while Indah Kiat Pulp & Paper shed 7.5%.
The Chinese yuan's depreciation is a negative sentiment for Indonesian commodity firms, Trimegah Securities said in a note.
In the spot market, the yuan opened at 6.6177 per dollar, and ended the onshore trading session at 6.6250 per dollar, the weakest official close in seven months.
Indonesia exports a substantial amount of coal to China.
An index of the country's 45 most liquid stocks ended 2.2% lower.
The rupiah plunged to its lowest since October 2015 against the dollar on extended outflows. A volatile currency has prompted the central bank to take protective measures for the economy.
Sentiment was also hurt as Asian stocks slumped to a nine-month low.
MSCI's broadest index of Asia-Pacific shares outside Japan was down 0.7% as Chinese stocks, coupled with the yuan, took a fresh beating.
Philippine shares dropped 1.5% after adding 2.4% in the previous session. Industrial and real estate stocks were among the biggest drags after Wednesday's gain on selective bargain-buying.
Index heavyweight SM Investments Corp ended 2.7% lower, while property developer SM Prime Holdings Inc fell 3.5%.
Meanwhile, Singapore shares closed slightly higher, but remained parched near eight-month lows.