For each of the previous instances in this interest rate cycle, the Hong Kong Monetary Authority and the Hong Kong banks followed the action of the US Federal reserve and cut Hong Kong interest rates. Not this time. With deposit rates now close to zero and lending margins under pressure, the HK banks have been at pains to talk up the market to try and preserve or improve their lending margins. It was no surprise to find that none of the major banks cut their prime lending rates (which is one of the two benchmarks for setting mortgage rates in Hong Kong). In effect, prime linked mortgages should not be affected by the latest interest rate cuts in the US. It remains to be seen whether the HIBOR linked mortgages will change at all (although I note in passing that banks are starting to be less willing to lend on HIBOR linked terms).
As a side note, although the banks did not cut their lending rates, they were quick to further reduce the already tiny yields on deposits.