A strategy where one co-owner of a property buys out the other's share so that one owner no longer counts as a property owner, usually to free that person to buy another property as a 'first' purchase and reduce Additional Buyer's Stamp Duty. In Singapore this works only for privately-owned property — HDB flats generally cannot be decoupled simply to buy a second home.
Example: Two co-owners of a private condo might decouple so one fully owns it and the other can buy a second property at lower ABSD. But the buy-out itself triggers Buyer's Stamp Duty on the transferred share (and possibly Seller's Stamp Duty if within the holding period), so the ABSD saving must be weighed against these costs. Confirm all rates with IRAS.