The Stock Exchange of Thailand (SET) announces the regulatory amendments to strengthen market supervision and investor confidence by restricting purchases of securities by high-frequency trading (HFT) investors to only securities with large market capitalization and high liquidity. The revisions aim to mitigate price volatility in small-cap and mid-cap securities potentially experiencing inadequate trading liquidity. Under the revised regulation which will take effect on July 7, 2025, securities eligible for purchase by HFT investors will be limited to:
- Common stocks, including securities held by foreign nationals (-F) and NVDRs, as follows:
- SET100 Index constituents
- Underlying stocks of DWs and Single Stock Futures (SSFs) which are SET100 Index constituents. Purchases of underlying stocks removed from the SET100 Index remain permissible until the corresponding DWs expire or the corresponding SSFs cease trading on TFEX.
- DWs, DRs, and ETFs
HFT investors holding securities outside these categories may maintain or sell such securities, but additional purchases thereof will be prohibited after the revised regulation takes effect.
For more information about the revised regulation, please visit SET website at www.set.or.th under the “Rules and Regulations” section, then “Circular Letters - Trading & Supervision,” and select the circular letter on “Eligible Securities for High-Frequency Trading (“HFT”) Investors.”
