The Hong Kong Monetary Authority (HKMA) intervened by purchasing nearly 6.4 billion HKD to stabilise the currency.
The Hong Kong dollar has been near the weaker limit of its trading range against the U.S. dollar.
Historical Context
Since 1983, the HKD has been anchored to the U.S. dollar via the Linked Exchange Rate System. The peg maintains the HKD at around 7.80 per U.S. dollar, with an allowable trading range from 7.75 to 7.85.
The HKMA operates a Currency Board System where each HKD issued is supported by U.S. dollar reserves at a fixed rate. This links the monetary base to foreign exchange inflows or outflows.
Through an intervention mechanism, when the HKD reaches the 7.75 level, the HKMA sells HKD, purchasing U.S. dollars, thus injecting liquidity. Conversely, when nearing 7.85, it buys HKD and sells U.S. dollars, withdrawing liquidity.
This approach ensures the HKD remains stable within its specified trading band.
The Hong Kong Monetary Authority is once again stepping in to defend the currency peg by buying up Hong Kong dollars. We’ve seen this happen today, with nearly 6.4 billion HKD being purchased to keep the exchange rate from weakening past its 7.85 limit against the US dollar. This action is a direct response to market forces pushing the HKD to the edge of its trading band.
Pressure and Market Impact
This pressure is largely due to the interest rate gap between the U.S. and Hong Kong. With the U.S. Federal Reserve holding rates firm around 5.0% in mid-2025 and Hong Kong’s one-month interbank rate (HIBOR) lagging at about 4.6%, traders are borrowing HKD to buy higher-yielding USD. This carry trade consistently puts downward pressure on the local currency.
Every time the HKMA intervenes like this, it tightens liquidity in the city’s banking system. We saw this exact pattern play out repeatedly back in 2023, where a series of interventions caused HIBOR rates to spike sharply to close the gap with U.S. rates. For derivative traders, this signals a clear opportunity to go long on HIBOR futures, anticipating that continued interventions will drive up short-term borrowing costs in the coming weeks.
These tightening financial conditions tend to weigh on the stock market. Higher borrowing costs hurt corporate earnings and can spook equity investors, a risk for a market like the Hang Seng Index that is already down about 6% this past quarter. This makes buying put options on the Hang Seng Index or its related ETFs a sensible hedge against the predictable side-effects of defending the currency peg.
While the pressure is high, betting against the HKMA has historically been a losing trade given their over US$415 billion in foreign reserves. A more prudent strategy involves selling volatility on the USD/HKD pair. By selling out-of-the-money call and put options, traders can collect premium based on the high probability that the HKMA will successfully keep the currency within its 7.75-7.85 band.
