The Stock Exchange of Thailand main index climbed 0.38%, or 5.88 points, to 1,567.19 on Tuesday.
Total trading value was 37 billion baht, with 6.4 billion shares changed hands.
SET50 index fell 0.41%, or 4.10 points, to 999.16 in trade worth 21.5 billion baht.
MAI retreated 0.09%, or 0.50 points, to 535.09 in transactions worth 1.8 billion baht.
Institutional investors bought 2 billion baht of shares, followed by foreigners (1.2 billion). Individual investors sold 2.6 billion baht while brokers offloaded shares worth 680.8 million baht in total.
Year-to-date, institutional investors were net buyers of 48.6 billion baht, followed by foreigners (2.8 billion). Individual investors sold 48 billion baht, followed by brokers (3.4 billion).