Under the Housing and Development Act, as long as there is one Singapore Citizen HDB flat owner, you will not be forced to sell your HDB flat in the event of a bankruptcy.
However, if your HDB flat has been financed with a mortgage loan and you are unable to repay your mortgage either to a bank or to HDB, the bank can seize and sell your flat through a mortgagee sale. HDB can also acquire your flat compulsorily.
The Official Assignee (OA)’s consent is not required if you would like to sell your HDB flat, as long as there is one Singapore Citizen HDB flat owner. Otherwise, you will need a letter of consent from the OA before you grant your prospective buyer an Option to Purchase.