South Korean stocks traded 6 per cent higher to stay above the unprecedented 7,300-point mark on Wednesday led by strong gains in semiconductor shares and rising optimism for a peace deal between the United States and Iran.

Opening 2.25 percent higher, the benchmark Korea Composite Stock Price Index (KOSPI) extended gains, adding 418.82 points, or 6.04 percent, to an all-time intraday high of 7,355.81 as of 11:20 a.m, reports Yonhap news agency.

With the surge, the bourse operator issued a buy-side sidecar at 9:06 a.m. to halt program-driven buy orders in KOSPI futures for five minutes.

The stock market pulled off a strong start following U.S. President Donald Trump's announcement to pause the U.S. efforts to guide ships through the Strait of Hormuz to finalize a deal with Iran.

Overnight on Wall Street, the S&P 500 and Nasdaq closed at record highs on artificial intelligence-related stocks.

In Seoul, semiconductor stocks led the rally. Top-cap Samsung Electronics surged 12.47 percent, and chipmaking rival SK hynix soared 10.3 percent.

Hanmi Semiconductor, a chip equipment manufacturer, rose 1.59 percent.

Top carmaker Hyundai Motor advanced 2.23 percent, and its auto parts affiliate Hyundai Mobis added 0.46 percent.

However, defence shares traded lower as industry leader Hanwha Aerospace fell 2.32 percent and Hyundai Rotem dropped 2.6 percent.

The Korean won was trading at 1,457.6 won against the U.S. dollar at 11:20 a.m., up 5.2 won from the previous session.

Meanwhile, South Korea's consumer prices rose at the fastest pace in 21 months in April, driven by soaring fuel costs amid the Middle East conflict, government data showed.

Consumer prices, a key gauge of inflation, increased 2.6 percent from a year earlier last month, according to the data from the Ministry of Data and Statistics. It marks the largest on-year increase since July 2024, when inflation climbed 2.6 percent.

The latest rise was driven by a surge in the price of petroleum products, which jumped 21.9 percent from a year earlier, marking the sharpest increase since July 2022.