South Korea’s authorities have tightened oversight of the FX market as the won (KRW) weakens, moving from guidance to closer supervision. The Financial Supervisory Service has cut the review cycle for major banks’ FX positions from monthly to weekly, and it may shift to a daily basis if conditions do not stabilise. The Bank of Korea and the Financial Supervisory Service are also set to launch joint inspections of major FX banks for the first time in 14 years, focusing on whether trading sought to move or pin exchange rates for improper gains, with breaches facing strict penalties.

USD/KRW has been consolidating around 1,520 after rising to 1,558 last Friday, its highest level since 2009. Year-to-date, KRW is down 5.4%, placing it third among Asian currencies, behind INR at -5.9% and IDR at -7.3%, while this week it has strengthened by more than 2% versus USD. In equities, the Kospi is up 83% so far this year despite a correction of over 12% from last week’s peak, after gaining 76% last year, and KRW pressure has coincided with net foreign equity outflows, higher oil prices and Middle East-related geopolitical uncertainty.

Policy Action As A Turning Point In FX Risk

We see the South Korean authorities’ direct intervention as a clear signal that they are trying to establish a ceiling for USD/KRW. Their shift from verbal warnings to active supervision means the risk of a sharp, policy-driven reversal has increased significantly. For now, we believe the days of easy gains from shorting the won are over.

This heightened scrutiny is likely to drive up implied volatility in the currency markets, making option strategies more interesting. We are looking at selling premium on USD/KRW, as the government’s actions could pin the exchange rate within a tighter range in the short term. Conversely, buying put options on the pair offers a limited-risk way to profit if the intervention proves successful and the won strengthens further.

Market Risks Persist Against Solid Fundamentals

The government’s stance is bolstered by solid fundamentals, as South Korea’s trade surplus reached nearly $5 billion last month. However, with WTI crude oil prices remaining above $80 a barrel, a key headwind for the import-dependent economy persists. This sets up a battle between official policy and persistent external pressures.

We are also watching the Kospi, which despite its recent 12% pullback, is still up an incredible 83% this year. A more severe correction in the stock market could easily trigger renewed foreign outflows, placing immediate pressure back on the won. The authorities can fight speculation, but they will struggle to fight a genuine capital flight if equity sentiment sours.

History shows these interventions can be forceful, as seen with the heavy dollar-selling campaigns in 2022 to defend the currency. Given the risk of being caught on the wrong side of such a move, we are reducing exposure to long USD/KRW positions. The prudent move is to wait and see how determined the Bank of Korea and FSS are in defending the currency against the market.