The Stock Exchange of Thailand will implement revised short-selling and high-frequency trading rules from Nov. 16. Stocks priced 5–50 THB will trade with reduced tick sizes to narrow bid-ask spreads and cut trading costs. Short selling will be restricted to higher-liquidity instruments: SET100 constituents, single-stock futures underlyings, depositary receipts and ETFs; short sales will be permitted only at or above the last traded price. The exchange will levy extra fees on accounts that submit

The Stock Exchange of Thailand will implement revised short-selling and high-frequency trading rules from Nov. 16. Stocks priced 5–50 THB will trade with reduced tick sizes to narrow bid-ask spreads and cut trading costs. Short selling will be restricted to higher-liquidity instruments: SET100 constituents, single-stock futures underlyings, depositary receipts and ETFs; short sales will be permitted only at or above the last traded price. The exchange will levy extra fees on accounts that submit large numbers of orders with relatively low execution rates. It will eliminate per-security dynamic price bands, relax restrictions on HFT participants’ eligible instruments, and remove minimum order resting-time requirements to improve order management. Trading hours for foreign-linked derivative warrants and ETFs will start at 08:00 (two hours earlier) from Nov. 16; closing times unchanged.