Seoul shares were flat on Tuesday, as investors locked in profits from a recent rally that drove the main index to all-time highs, but sharp gains in Samsung Electronics helped the market fend off stiff selling pressure.
Investors were also cautious ahead of index compiler FTSE's decision on whether to upgrade Korea to "developed market" status from the current "advanced emerging market" designation. An announcement is expected on Wednesday.
The benchmark Korea Composite Stock Price Index (KOSPI) fell 0.02 percent to 1,1158.12, after setting a closing record in each of the four prior sessions.
"I'm not sure if the market can go up any further. We may need a correction period," said Kim Yung-min, an equity strategist at Korea Investment Trust Management.
Kim recommended investors focus in the short term on larger stocks less volatile during correction periods and which would provide an easier exit from the market.
Hyundai Motor Co, the country's biggest auto maker, slipped 0.9 percent to 77,300 won, while smaller affiliate Kia Motors Corp fell 0.27 percent to 18,250 won after surging 17.3 percent over the past five sessions.
South Korea's No 2 carmaker reached a tentative wage deal with its labour union on Tuesday after a dispute that it estimates cost more than $400 million in lost production.
Institutional investors were leading sellers on Tuesday, contributing to the broader index's decline.
A surge in new money from retail investors via stock funds developed and sold by investment houses had been a key factor behind the nearly 30 percent gain in the KOSPI this year.
Steel maker POSCO Co Ltd fell 0.69 percent to 215,500 won, while Woori Investment and Securities Co fell 2.66 percent to 12,800 won.