Fed Hikes 0.25%:
HK Banks Hold Prime Rate at 5%

What happened

The Federal Open Market Committee decided on 16 September 2026 to raise the target range for the federal funds rate by one quarter of a percentage point, to 3.75% to 4.00%. The vote was unanimous at 12–0. It is widely described as the first increase in more than three years, and it marks the end of the easing cycle.

In Hong Kong, the Monetary Authority raised its Base Rate from 4.00% to 4.25% on 17 September, also by a quarter point. The Base Rate is the rate the HKMA charges at its discount window and moves automatically with US rates.

Sources: FOMC statement, 16 September 2026; HKMA daily interbank liquidity figures, 17 September 2026. The Prime rate is a commercial decision by each bank; check the latest quote from your lender.

The counter-intuitive part: HIBOR fell

Official data shows the one-month Hong Kong Interbank Offered Rate stood at 2.95% on 16 September. On 17 September, the day after the hike, it did not rise. It fell to 2.90%. The overnight rate edged down from 2.03% to 2.02%, and the aggregate balance stayed at roughly HK$54 billion.

That reflects ample local liquidity. The HKMA Base Rate is a ceiling of sorts: unless banks actually need to borrow from the HKMA, it does not push market rates up. In other words, an American rate hike does not automatically make Hong Kong mortgages more expensive.

The real risk is the next step

The Prime rate is not an official rate. It is set commercially by each bank. After the HKMA move, HSBC, Hang Seng and BOCHK all announced on the same day that Prime would stay at 5.00%, which suggests local funding remains comfortable and lenders see no need to pass on costs immediately.

Two details are worth watching. First, media reports quote bank economists expecting a possible follow-on increase of up to a quarter point before the end of the year. Second, the HKMA has said that holding rates steady helps cushion the property market, while banks may reduce mortgage cash rebates instead.

That pattern has appeared before: rather than raise rates outright, banks trim the incentives first. For anyone buying or refinancing, a smaller cash rebate has the same effect as a rate increase.

It is also worth noting that lenders are not moving in lockstep. ICBC (Asia) announced on its own website on 17 September that it was cutting its Hong Kong Prime rate and savings deposit rate — a reminder that “all Hong Kong banks follow the Fed” is not a rule.

If Prime rises 0.25pt: what it costs

Should banks add a quarter point, the effective P-based rate would move from 3.25% to 3.50%. The table below shows the monthly change over a 30-year term.

Calculated on an amortising basis over a 30-year term. Excludes mortgage insurance premiums, fees and cash rebates. Illustrative only.

The lifetime interest difference is larger still. Over the full term, the extra cost comes to roughly HK$199,000 on a HK$4 million loan, HK$299,000 on HK$6 million and HK$399,000 on HK$8 million. A quarter point is not a few hundred dollars.

Global context: more than the US

This is a synchronised tightening. The Bank of Japan raised its policy rate by a quarter point to 1.25% on 18 September, the highest in 31 years, while the Bank of England held its policy rate at 3.75% the same day. Attention has shifted from whether rates rise to how many times.

For Hong Kong, the currency peg means local rates must eventually track US rates over the long run, while short-term moves are driven by local supply and demand. That is exactly why the HKMA can raise its Base Rate while banks leave Prime untouched.

Three things mortgage holders can do now

First, find your facility letter and check three numbers. Is your mortgage H-based or P-based? What is the spread? What is the cap? Those three figures determine how exposed you are. Enter your loan size and term into a mortgage calculator to see the payment at different rates.

Second, work with numbers, not nerves. Rate headlines create anxiety, but anxiety does not help decide anything. On a HK$4 million loan, a quarter point is HK$554 a month — whether that requires trimming spending or making prepayments is a judgement only your own figures can support.

Third, compare total cost, not just the rate. Banks can raise Prime, but they can also cut cash rebates, extend clawback periods or adjust cap levels. Before refinancing, compare rate, cash rebate, clawback period and cap together, then use a remortgage calculator to find the break-even point.

Questions

Related reading

For a full comparison of the two structures, see H-based vs P-based Mortgages in 2026. For how US bond yields feed through to Hong Kong lending and deposit rates, read US 10-year yields above 4.8%.