Federal Reserve just announced no change in interest rate, but the trend of increasing US interest rate is almost a consensus of the market. Due to the currency board arrangement in Hong Kong, the 1-month HK interbank offer rate (HIBOR 1m) has been going up rapidly in recent months, as shown in the chart below.
source: HKMA (Nov., 2, 2017) http://www.hkma.gov.hk/eng/market-data-and-statistics/monthly-statistical-bulletin/table.shtml#section6
The most recent HIBOR 1m is 0.815% (2 Nov 2017), which breaks the 9-year record since 2008. Most mortgages are repaid based on HIBOR, the upsurge of HIBOR would immediately affect the monthly payment of mortgages.