The Blubber

Thailand is implementing a temporary ban on short selling and introducing tighter trading rules in an effort to contain market volatility amid global turbulence triggered by sweeping U.S. tariffs.

The Stock Exchange of Thailand (SET) announced on Monday that short selling of all securities—except for market makers—will be prohibited from Tuesday, April 8, through Friday, April 11. The exchange will also narrow the allowable price movement bands for stocks. The decision came after SET's board held an emergency meeting, though local financial markets were closed for a public holiday.

According to SET, the measures aim to ease potential volatility and give investors time to respond to the U.S. tariff shock that has sent global markets tumbling. Thailand was hit with a 36% tariff, placing it among the most heavily affected nations in Southeast Asia. The country’s trade surplus with the U.S. stood at $45 billion last year.

Thailand's equities had already been under pressure even before President Trump’s latest tariff announcements. The Thai stock market has been one of the weakest performers globally this year, weighed down by shrinking corporate earnings and a gloomy economic forecast. The benchmark SET index fell 4.3% last week alone, deepening its year-to-date losses to nearly 20% and pushing it to a five-year low.

The SET said it will maintain close oversight of the market and adjust the restrictions as needed based on evolving conditions. The temporary rules will also apply to the Market for Alternative Investment and the Thailand Futures Exchange.