In the morning session, Krungsri Securities expected the index on Friday to rise to between 1,655 and 1,660 points after Opec+ raised its 2022 oil demand forecast and US jobless claims fell.
However, it advised investors to beware of mass sell-offs of shares in response to signs of overbought stocks pressuring the index.
The 10 stocks with the highest trade value today were GULF, DELTA, CPALL, MAKRO, KBANK, PTT, BANPU, GPSC, BBL and SUPER.
Other Asian indices were mixed:
Japan's Nikkei Index closed at 29,128.11, up 584.60 points or 2.05 per cent.
China's Shanghai SE Composite Index closed at 3,581.73, down 15.31 points or 0.43 per cent, while the Shenzhen SE Component Index closed at 14,179.86, down 97.47 points or 0.68 per cent.
Hong Kong's Hang Seng Index closed at 25,901.99, down 188.44 points or 0.72 per cent.
South Korea's KOSPI closed at 3,201.06, up 25.21 points or 0.79 per cent.
Taiwan's TAIEX closed at 17,516.92, up 197.16 points or 1.14 per cent.