Yes, you can buy a condo after selling off your HDB. However, if you purchase a second house, you’ll first have to pay the ABSD as usual. You can apply for a remission if you sell your first home within six months of buying the second one. If the second property is under development, you must sell your first house within six months of the second property getting its Temporary Occupation Permit (TOP) or Certificate of Statutory Completion (CSC), whichever is earlier.