Classifying Regimes During Thin Holiday Volume
When SET aggregate volume falls below sixty percent of the twenty-day average, we prefix regime labels with 'thin-' to remind size rules to halve until normal liquidity returns.
False expansion appears when one large block trade prints at the edge of the range. ATR rises but follow-through stalls. Compare tick count or trade number if your feed provides it; a single print should not flip the regime.
Our workshop workbook includes a Songkran case study from 2025 where ATR doubled on three banking names while the index barely moved. Participants who applied the thin-volume prefix avoided doubling size into a mean-reversion week.
After holidays, allow one full session of normal volume before removing the prefix. Opening day gaps often reverse once corporate desks return.
Keep a calendar overlay on your chart printouts marking Thai public holidays and US market closures. Regime reading without calendar context invites misclassification every April and December.