SET to overhaul Short Sell and HFT rules pending SEC approval

Prachachat•Economy•8d ago

Reader Briefing

The Stock Exchange of Thailand is proposing updates to short selling and high-frequency trading rules pending approval from the SEC in September-October 2026.

•The Stock Exchange of Thailand board has approved measures to reduce price volatility and control trading behavior.
•The proposal is currently under consideration by the Securities and Exchange Commission (SEC).
•Approval from the SEC is expected between September and October 2026.
•The Stock Exchange of Thailand conducted public hearings on these measures from May 13-29, 2026.

Overview

•The Stock Exchange of Thailand measures to reduce volatility and control trading behavior have been approved by the Stock Exchange of Thailand board.
•The Stock Exchange of Thailand is awaiting approval from the Securities and Exchange Commission (SEC), expected in September-October 2026.
•The Stock Exchange of Thailand held public hearings with investors and stakeholders from May 13-29, 2026.
•Proposed volatility measures include adjusting the Uptick Rule for short selling, reviewing the list of short-sellable securities, and canceling the Dynamic Price Band (DPB) for individual securities.
•Proposed trading behavior measures include requiring registration for High-Frequency Trading (HFT), removing restrictions on securities that HFT can trade, and canceling the Minimum Resting Time (MRT).
•Paweena Sriphothong stated that inappropriate trading behavior in the Thai stock market has improved.
•Paweena Sriphothong noted the improvement follows a change where the Stock Exchange of Thailand now discloses inappropriate behavior data to all securities companies instead of sending warnings to individual firms.
•The disclosure of inappropriate trading behavior to all securities companies has resulted in a decrease in risky trading behavior.

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Key Entities

Organization

Stock Exchange of Thailand(ตลาดหลักทรัพย์แห่งประเทศไทย)ℹ️

The organization proposing new trading rules to reduce price volatility and control trading behavior.

Securities and Exchange Commission(ก.ล.ต.)ℹ️

The regulatory body responsible for reviewing and approving the Stock Exchange of Thailand's proposed trading measures.

Person

Paweena Sriphothong(ปวีณา ศรีโพธิ์ทอง)

Deputy Manager and Head of Market Supervision at the Stock Exchange of Thailand.

Policy

Uptick Rule

A measure for short selling that is being adjusted by the Stock Exchange of Thailand.

Dynamic Price Band

A price trading frame for individual securities that the Stock Exchange of Thailand proposes to cancel.

Minimum Resting Time

A trading measure that the Stock Exchange of Thailand proposes to cancel.