I just got a call from my Premier Relationship Manager reassuring me that nothing will change on my accounts (which I had assumed) and that he will remain my PRM. He mentioned there will be a consolidation of branches and wasn't sure which of the ones in the Bay Area would survive. Not an issue for me, since I haven't set foot in a US branch for several years.
I asked about credit cards and he said ALL credit cards are being kept by HSBC, even if the attached bank account is being sold to Citizens or Cathay. He said the purchasing banks did not want to take on the CCs. That doesn't seem to entirely jive with what others have been told, so who knows.