BANGKOK, Thailand – The Stock Exchange of Thailand (SET) will introduce eight revised trading measures on November 16, including smaller minimum price increments for certain shares and tighter short-selling rules designed to reduce abnormal price volatility and improve market fairness.
SET President Asadej Kongsiri said the measures follow a public consultation with investors and market participants in May and have received approval from the Securities and Exchange Commission board.
The changes aim to balance market liquidity and stability, reduce trading costs and strengthen confidence in Thailand’s capital market, while bringing trading rules more closely into line with international practices.
The eight measures are:
- Smaller price increments: The SET will reduce tick sizes for shares priced between 5 and 50 baht per share, narrowing price spreads and making it easier for buy and sell orders to match.
- Revised short-selling price rules: Under normal conditions, short sales must be placed at or above the latest traded price under a Zero-Plus Tick rule. If a security closes down at least 10% from the previous day’s closing price, the stricter Uptick rule will apply on the next trading day, requiring short sales to be priced above the latest trade.
- Restrictions on eligible short-sale securities: Short selling will be limited to highly liquid securities, including SET100 constituents, underlying securities of Single Stock Futures, and depositary receipts (DRs) and exchange-traded funds (ETFs).
- Registration requirements for certain trading activity: The SET will refine the criteria for registering trading activity that uses dedicated application programming interfaces (APIs) or high-frequency trading (HFT). Factors may include order frequency and speed, end-of-day positions and daily trading value.
- Additional fees for excessive order activity: Accounts with an order-to-trade ratio exceeding 50 and an average of more than 50 orders per minute will face an additional fee of 0.15 baht per order for orders exceeding 15,000 per day. The measure aims to reflect the cost of using exchange systems and discourage orders placed without a genuine intention to trade.
- Removal of Dynamic Price Band limits: The SET will abolish security-specific Dynamic Price Band limits, reducing trading restrictions, particularly for less liquid shares.
- Removal of restrictions on securities available to HFT traders: High-frequency traders will no longer face limits on which securities they can trade, giving investors across different groups more equal access to the market.
- Removal of Minimum Resting Time: The SET will abolish the minimum time an order must remain in the system, allowing more flexible order management and reducing operational burdens for member firms.
The SET said the revised framework is intended to reflect actual trading behaviour while maintaining appropriate oversight and supporting a fairer, more efficient market. Investors can find further details on the SET website under its rules and regulations section.
