Why not now focus on the Thai big cap. blue chip stocks?

Because these are often in the often over-rated in the service sector like Telecom, Banks & Energy or electronics like DELTA; not exports, tourism or domestic consumption and manufacturing which Thailand is often competitive at.  Most larger capitalized stocks are relatively expensively valued (high p/e) and so often pay lower dividends yields. One reason for this is that many are speculated on/around.  Overall, I prefer select smaller cap shares as they are often undervalued, have faster growing earnings and pay higher dividends.  Why should smaller capitalize Thai growth companies sell at the discount to the market p/e? Even while many pay higher then SET averaged dividends and have stronger long-term  growth rates.  During Covit-19 and just post however, smaller and mid cap stocks outperformed the SET overall this is in large part due to Thai retail investors bigger participation.   But alas this changed back since to a far more speculative driven SET market -which is just one reason why year 2023 was one of the worst on record.