The South Korean won has tumbled to its weakest level against the U.S. dollar in 17 years, marking a significant deterioration in the currency's standing.

The sharp depreciation occurred on Monday as foreign investors accelerated their sell-off of South Korean equities, exacerbating pressure on the local currency.

7 trillion won ($3.3 billion) of South Korean stocks in May.

This move follows data released earlier in the week showing that foreign investors offloaded a record net 4.7 trillion won ($3.3 billion) of South Korean stocks in May.

That figure represents the highest monthly sell-off in the market's history, underscoring a deepening liquidity concern for the region's second-largest economy.

The combination of historic equity outflows and currency weakness suggests that external capital is retreating from Korean assets at an unprecedented pace.

Traders are now focused on whether the Bank of Korea will intervene to stabilize the won or if further devaluation is likely as selling pressure persists.