Market Reactions - The Korea Exchange activated the KOSPI index circuit breaker after a 5% drop in KOSPI 200 futures, leading to a 5-minute suspension of program trading [1] - The Nikkei 225 index saw its intraday decline expand to 4% [2]

Group 1 - The KOSPI index experienced a significant increase, leading to a 5% rise in KOSPI 200 futures, which triggered the circuit breaker mechanism on March 18 [1] - The circuit breaker resulted in a temporary suspension of programmatic trading for 5 minutes [1]