The Stock Exchange of Thailand index closed up 3.27 points or 0.24% to 1379.53 at midday on Tuesday.
Trading value was 9.77 billion baht, with 1.56 billion shares changed hands.
The SET50 index ended at 937.59 points, up 1.83 points, or 0.20%, with total trading value of 6.58 billion baht.
The MAI index went up 1.43 points, or 0.36%, to close at 396.76 points, with total transaction value of 523.72 million baht.
Leading trade by value were: KBANK (+0.56%), ADVANC (+1.33% even on XD), SCB (+0.32%), PTTEP (+0.96%) and BBL (+0.84%)