At the close, the SET index stood at 1,623.48 points, gaining 5.75 points or 0.36 per cent on turnover of Bt50.77 billion. The turnover of the last hour was as high as Bt10 billion.
The previous 19-year high of 1,622.48 points was registered on May 10.
At noon, the index hit 1,627.51.
In the morning, Korea ended up 1.02 per cent, the Philippines 0.62 per cent, Taiwan 0.19 per cent, while Hong Kong and Japan down by 0.33 per cent.
US reported a bettern-than-expected increase in retail sales while China announced the lower-than-expected growth in industrial output for April.
Locally, some Thai companies like Charoen Pokphand Foods showed the better-than-expected results in the first quarter.
Asia Plus urged investors to focus on stocks of which earnings could beat forecasts, like Sansiri, Quality Houses, Singer (Thailand), Bangkok Expressway and CP All.