The Stock Exchange of Thailand climbed 0.50%, or 8.60 points, to 1,732.31 on Tuesday.
Total trading value was 65.8 billion baht, with 10.4 billion shares changed hands.
The SET50 index advanced 0.40%, or 4.48 points, to 1,122.30 in trade worth 41.7 billion baht.
MAI gained 0.14%, or 0.77 points, to 534.51 in transactions worth 2.6 billion baht.
Institutional investors were net buyers of 3.9 billion baht worth of shares, followed by brokers (3.4 billion baht). Individual investors sold 4.5 billion baht, followed by foreigners (2.8 billion baht).
Year-to-date, institutional investors were net buyers of 95.4 billion baht, followed by brokers (17 billion baht). Retail investors were net sellers of 83.9 billion baht, followed by foreigners (28.6 billion baht).