South Korea's Kospi plunges 10.84 percent on Tuesday as a circuit breaker halts Seoul trading

South Korea's Kospi index closed down 732.09 points, or 10.84 percent, at 6,023.66 on Tuesday, 28 July 2026 (6 Mordad 1405). According to Korean media reports, that is the second largest fall in the index's history in points and the fourth largest in percentage terms. The Kosdaq index fell 7.7 percent.

The session was interrupted twice by protective mechanisms: a program sell sidecar was triggered at around 9:06 a.m. local time, and after 10 a.m. a circuit breaker halted trading for 20 minutes. The index fell as low as 5,992.91 during the session, slipping below the 6,000 mark for the first time in nearly three and a half months, before finishing just above that threshold. Korea's two chipmaking giants bore the brunt: Samsung Electronics fell 13.4 percent and SK Hynix 14.7 percent.

The selling was driven by fresh concern over Chinese memory capacity and the durability of the artificial intelligence boom: CXMT's headline grabbing debut on the Shanghai STAR Market on Monday, 27 July, reports that China has begun mass producing deep ultraviolet lithography equipment, and Nvidia's overnight fall on Wall Street over circular financing worries. The selling reached Tokyo as well: the Nikkei 225 closed the same day down 2,566.27 points, or 3.95 percent, at 62,364.92, and the broader Topix fell 102.48 points, or 2.52 percent, to 3,963.59. For Iran's market, the significance runs through global risk appetite, the variable that shapes behaviour in the crypto and tether market and the expectations of domestic investors.