The KOSPI fell to the 5,500 level after breaking below 6,000, triggering Level 1 circuit breakers in both the KOSPI and Kosdaq markets for a second straight day.

The Korea Exchange said a Level 1 circuit breaker was triggered in the Kosdaq market at 12:19:12 p.m.

At the time, the Kosdaq stood at 649.00, down 56.85 points, or 8.05 percent, from the previous session's close of 705.85. Trading in all listed issues was halted for 20 minutes after the index stayed down more than 8 percent for 1 minute.

A Level 1 circuit breaker was triggered in the main board market at 12:32:32 p.m.

The KOSPI stood at 5,532.33, down 491.33 points, or 8.15 percent, from the previous session's close of 6,023.66. After falling below 6,000 intraday for the first time the previous day, losses widened on the day and it retreated to the 5,500 level.

When a circuit breaker is triggered, order acceptance is suspended except for cancel orders, and trading in all listed issues is halted for 20 minutes. Before trading resumes, orders are accepted for 10 minutes and then single-price trading takes place.

Both markets also triggered sell-sidecar measures ahead of the circuit breakers.

In the main board market, the effectiveness of program sell orders was suspended for 5 minutes after the KOSPI200 futures fell 49.16 points, or 5.15 percent, from the reference price to 903.80 at 10:55:07 a.m.

In the Kosdaq market, a sell-sidecar was triggered 1 minute later, at 10:56:07 a.m. At the time, Kosdaq150 futures fell 6.21 percent and the Kosdaq150 fell 6.30 percent from the previous session.

Both sell-sidecar measures and Level 1 circuit breakers were triggered in the KOSPI and Kosdaq markets for a second straight trading day.

On July 28, sell-sidecar measures were triggered in both markets and trading was halted for 20 minutes after the KOSPI and Kosdaq each fell more than 8 percent. The KOSPI closed at the 6,023 level, down 10.84 percent, and the Kosdaq ended at the 705 level, down 7.72 percent.

The market sees the fall as having widened as weakness in large semiconductor stocks, foreign selling and concerns about supply and demand related to single-stock leveraged exchange-traded funds overlapped.

Financial authorities said they would quickly push ahead with supplemental measures for single-stock leveraged ETFs and would also review additional steps depending on market conditions.