Korea's bourse operator on Tuesday activated a circuit breaker for the benchmark Korea Composite Stock Price Index (KOSPI) after stocks tumbled on heavy losses in technology heavyweights. Trading of KOSPI-listed shares was halted for 20 minutes. The Korea Exchange (KRX) triggered the measure at around 1:51 p.m. after the KOSPI plunged more than 8 percent from the previous session's close. The benchmark index came under heavy selling pressure as investors moved to locked in profits and offloaded large-cap technology stocks. It marked the sixth time this year that the KRX has activated a circuit breaker.