As you are a Singapore citizen and currently own just one residential property, there will not be any ABSD payable when you acquire additional ownership in the same property from your co-owner, your mother.

However, please take note that BSD will still apply to the acquisition of your mother’s 80% share of the property.

Should you decide to purchase another private flat after acquiring your mother's share, the purchase of the private flat will be your second property and you will be subject to ABSD at the applicable rate.