Two main plans: H-plan and P-plan
The H-plan (HIBOR Plan) ties its rate to the Hong Kong Interbank Offered Rate (HIBOR), with a fixed spread on top, e.g. H+1.3%. Because HIBOR moves daily, the H-plan rate fluctuates with market liquidity.
The P-plan (Prime Plan) ties to the Prime rate (P), e.g. P-2.5%. Prime is set by each bank and changes far less often than HIBOR, so the P-plan rate is more stable.
The cap, not the rate, sets your ceiling
Both plans set a cap: the H-plan usually caps at P minus a margin, and the P-plan caps at its own P minus margin. No matter how high HIBOR climbs, your mortgage rate cannot exceed the cap.
This is what makes Hong Kong mortgages different from many overseas floating-rate loans: the cap gives your payment a predictable ceiling. When comparing plans, look at the cap, not just today's low rate.
A 1% rate rise: how much more?
On a HK$5M loan over 30 years, moving from 3.5% to 4.5% adds several thousand dollars to the monthly payment, and the lifetime interest gap can exceed HK$1M. A single percentage point looks small, but spread over decades the compounding amplifies it.
So don't just test 'today's rate' — run several. Enter price, down payment, term and a few rate assumptions into the mortgage calculator to see the payment and total interest gap directly.
Where the current rate stands
Both HIBOR and Prime move with US rates and local liquidity. The most direct way to see the current level is the H-plan and P-plan rates published by the major banks, or data from the HKMA and the Hong Kong Association of Banks.
But published caps and spreads shift with market conditions; the best plan today may not be best in six months. Before signing, get quotes from several banks and compare.
Three more gates beyond the rate
The monthly payment is only one part. Banks also run a stress test (assuming rates rise, you must still afford it), review your income and debt ratios, and set the loan-to-value ratio by property and loan size; high LTV also requires mortgage insurance.
Consider all of these for the full 'can I afford it' answer. First test different rates in the mortgage calculator, then check how much you can borrow with the mortgage-capacity tool — the two steps together are safer.