The Stock Exchange of Thailand climbed 0.30%, or 5.17 points, to 1,742.08 on Friday.
Total trading value was 40.1 billion baht, with 6.7 billion shares changed hands.
The SET50 index advanced 0.35%, or 3.91 points, to 1,128.48 in trade worth 26 billion baht.
MAI gained 0.18%, or 0.97 points, to 540.25 in transactions worth 2.5 billion baht.
Institutional investors were net buyers of 429 million baht worth of shares, followed by foreigners (793.7 million baht) and brokers (261.5 billion baht). Individual investors sold 1.5 billion baht.
Year-to-date, institutional investors were net buyers of 96.9 billion baht, followed by brokers (18.8 billion baht). Retail investors were net sellers of 88.2 billion baht, followed by foreigners (27.5 billion baht).