Where a Property Owner already owns a partial interest in a property (either as joint tenant or tenancy in common), the Additional Buyer Stamp Duty (ABSD) rate [based on 6 Jul 2018 Adjusted Rate] applicable for the acquisition (eg. purchase) of additional interest in the same property will depend on the number of residential properties he already owns at the time of the acquisition.

Therefore, if a Singapore Citizen only owns a partial interest in 1 property, his acquisition of additional share in the same property would not be subject to ABSD. But if he already owns partial interests in both properties A and B, his acquisition of additional share in property A or B or both would be subject to ABSD at the relevant rate as he owns 2 properties at the time of the acquisition of additional interest.

If a Singapore Permanent Resident only owns a partial interest in one property, his acquisition of additional interest in the same property would be subject to ABSD at the relevant rate. But if he already owns partial interests in both properties A and B, his acquisition of additional share in property A or B or both would be subject to ABSD at the relevant rate as he owns 2 properties at the time of the acquisition of additional interest.

[Caution Note: the above may be inaccurate and/or contains errors, and kindly do not rely on the same without obtaining proper legal advice based on your scenario. Please note that government policies and laws change from time to time. If you chose to rely on the above information, you are doing so at your own risk.]