South Korea’s stock market has swung wildly in recent days, underscoring how the world’s best-performing equities market last year is turning into its most volatile one.

The benchmark Kospi index

plunged as much as 12% on Wednesday, marking its largest single-day drop on record, before staging a powerful rebound in the next session, up nearly 10%, marking its best day since 2008. It was trading over 1% lower on Friday.

The whipsaw comes as investors reassess risks from the escalating war in the Middle East, which has sent oil prices surging and rattled markets globally, and the market’s concentration in a few stocks.

While the global risk-off mood has played a major role, experts said Korean market’s concentration in two memory giants and its sensitivity to energy shocks has made it particularly vulnerable to sharp swings.