The KOSPI on Monday surged more than 5 percent to recover the 8,500 level. Easing war risk between the United States and Iran, the end of a SpaceX listing event and stability in the won-dollar exchange rate combined to draw foreign and institutional buying. A buy-sidecar was triggered during the session on the main board.

The KOSPI closed up 422.36 points, or 5.20 percent, at 8,545.98. The index opened up 402.50 points, or 4.95 percent, at 8,526.12 and rose as high as the 8,600 level during the session.

The KOSPI climbed above 8,500 shortly after the open. The move was driven largely by reports that the United States and Iran reached an initial agreement to end the war and resume passage through the Strait of Hormuz, easing geopolitical risk. Falling international oil prices and U.S. Treasury yields also helped, as risk appetite recovered.

A buy-sidecar was triggered during the surge. The Korea Exchange halted the effectiveness of program buy orders for 5 minutes on the main board at 9:06:02 a.m. At the time, the KOSPI 200 futures price was up 66.00 points, or 5.07 percent, from the previous session at 1,365.85.

The KOSPI buy-sidecar was triggered for a second straight session, following June 12. This month, both buy- and sell-sidecars have occurred in succession on the KOSPI market, extending a volatile trend.

Foreigners and institutions led the flow. On the main board, foreigners were net buyers of 994.4 billion won and institutions bought a net 525.5 billion won. Retail investors were net sellers of 1.48 trillion won. Foreigners posted net buying for a second straight session after net purchases in the 2 trillion won range on June 12.

Most top market-cap stocks rose. Samsung Electronics closed up 14,500 won, or 4.50 percent, at 337,000 won. SK Hynix ended up 138,000 won, or 6.42 percent, at 2,288,000 won.

Elsewhere, SK Square rose 4.05 percent and Samsung Electro-Mechanics gained 16.63 percent. Hyundai Motor climbed 6.59 percent, LG Energy Solution rose 5.13 percent, Samsung Life added 9.73 percent, Samsung C&T rose 14.58 percent and HD Hyundai Heavy Industries gained 9.85 percent.

The end of the SpaceX listing event was also cited as a factor that eased supply pressure. Earlier, the market viewed sales of existing shares and potential fund shifts to participate in the SpaceX offering as a burden.

With that uncertainty easing after the listing, an interpretation has emerged that foreign buying resumed, centered on large domestic stocks and semiconductor shares.

The Kosdaq also rose. The junior index closed up 4.98 points, or 0.48 percent, at 1,034.03. Gains were limited compared with the KOSPI's surge of more than 5 percent led by a rebound in heavyweight shares.

On the Seoul foreign exchange market, the won stood at 1,513.50 per dollar, up 1.20 won from the previous session. With the rate falling back to the low 1,510s, foreign flow pressure also eased somewhat.

Brokerages have said easing war risk and the end of the SpaceX listing event led to foreigners returning to the market.

Jaewon Lee (이재원), an analyst at Yuanta Securities, said, "The end of the SpaceX supply-and-demand shift event, easing geopolitical conflict and reduced volatility in the won-dollar exchange rate together caused foreigners to return."