Simulated case study: a hypothetical scenario to illustrate the rules. Not a real client or transaction. Figures as at 10 October 2026.
Aaron and Joy, both 42 and Singapore citizens, jointly own a condo bought in 2017. If Joy buys Aaron's 50% share at an assumed market value of S$1,100,000, she pays S$28,600 in Buyer's Stamp Duty and, as a Singapore citizen buying more of the only home she owns, no ABSD. Aaron must refund his CPF use plus accrued interest. Under these assumptions, if Aaron later buys a home on his own he would be buying his first property; but IRAS can disregard arrangements made mainly to reduce stamp duty and add a 50% surcharge.
Figures as at 10 October 2026. Check the official source before acting.
The situation
| Assumption | Value |
|---|---|
| Owners | Aaron and Joy, married, both 42, Singapore citizens, joint owners of one condo |
| Bought | 2017, for S$1,650,000 |
| Current market value (assumed valuation) | S$2,200,000 |
| Outstanding home loan | S$700,000 |
| Transaction | Joy buys Aaron's 50% share at market value: S$1,100,000 |
| Aaron's CPF used plus accrued interest (assumed) | S$345,000 |
| Joy's gross monthly income | S$16,000, no other debts |
| Joy's own funds for the purchase | S$250,000 (cash and CPF) |
| Later purchase | Aaron buys a S$1,750,000 condo on his own |
The rules that apply
| Rule | What it says | Source and date |
|---|---|---|
| ABSD on buying a co-owner's share | A Singapore citizen who owns only this property and buys more of it from the co-owner pays no ABSD; BSD applies | IRAS ABSD) |
| Property count | Any partial interest counts as owning that property | IRAS ABSD |
| Buyer's Stamp Duty | 1% to 6% in tiers, on the price or market value of the share, whichever is higher | IRAS BSD), since 15 Feb 2023 |
| Seller's Stamp Duty | 12/8/4% within 3 years for purchases 11 Mar 2017 to 3 Jul 2025; 16/12/8/4% within 4 years for purchases from 4 Jul 2025 | IRAS SSD-for-residential-property) |
| CPF refund | Outgoing owner refunds CPF principal used plus accrued interest, on CPF's part-share formula | CPF Board |
| TDSR | All debt up to 55% of income, tested at 4% | MAS |
| Loan-to-value | 75%, or 55% if the tenure runs past age 65 | MAS |
| Anti-avoidance | IRAS may disregard or vary arrangements to avoid stamp duty, claw back duty and impose a 50% surcharge (Stamp Duties Act s.33A) | IRAS ABSD; MOF, April 2024 |
The numbers
Step 1: Joy's stamp duty on the 50% share (S$1,100,000)
- 1% of S$180,000 = S$1,800
- 2% of S$180,000 = S$3,600
- 3% of S$640,000 = S$19,200
- 4% of S$100,000 = S$4,000
- BSD: S$28,600
- ABSD: S$0 (Singapore citizen, only property, buying more of the same property)
- SSD for Aaron: S$0, because the condo was bought in 2017 and held for more than 3 years
Step 2: What Aaron receives
| Item | Amount |
|---|---|
| Price of his share | S$1,100,000 |
| Less his 50% of the outstanding loan | − S$350,000 |
| Less CPF refund to his own CPF account (assumed) | − S$345,000 |
| Cash to Aaron | S$405,000 |
The CPF refund goes back into Aaron's own CPF account; it is not a cost. CPF's actual figure for a part-share sale uses its own formula, so the split between cash and CPF may differ.
Step 3: Joy's financing
- She must pay S$1,100,000 for the share (part of which repays Aaron's half of the existing loan) and refinance her own S$350,000 half of the loan: S$1,450,000 in total.
- Using S$250,000 of her own funds, she needs a loan of about S$1,200,000.
- To keep the 75% LTV limit, the tenure must end by age 65: 23 years (276 months).
- Stress-test instalment at 4%: S$1,200,000 × 0.0055475 = about S$6,657 a month, or 41.6% of S$16,000, within the 55% TDSR.
- Her maximum under TDSR would be 55% × S$16,000 = S$8,800 a month, or about S$1,586,300 over 23 years.
Step 4: Aaron's later purchase of a S$1,750,000 condo
- BSD: S$1,800 + S$3,600 + S$19,200 + S$20,000 + 5% of S$250,000 (S$12,500) = S$57,100
- With no residential property in his name, his ABSD rate would be 0% as a Singapore citizen's first property.
- For comparison, if the couple had bought that condo while still owning their first home, ABSD would have been 20% × S$1,750,000 = S$350,000.
Under these assumptions, the share transfer costs S$28,600 in BSD plus legal and financing costs. But the comparison above is exactly what IRAS examines. Whether an arrangement is tax avoidance depends on the facts. IRAS can treat the steps as one transaction, recover the ABSD and add a 50% surcharge. A genuine sale of a full share at market value, with real financing and change of ownership, is different from a token 1% transfer, but only IRAS decides how the rules apply to a given case.
What changes the answer
- If Joy were a PR: IRAS treats her purchase of the extra share as her second property, so 30% ABSD (S$330,000 on the S$1,100,000 share) would apply, but IRAS's partial remission for acquiring an additional interest in a property the buyer already part-owns may reduce it to 5% (S$55,000), if the conditions are met.
- If the couple owned another property: buying the spouse's share would count as a further property, with ABSD at 20% or 30% for a Singapore citizen.
- If the condo were bought on or after 4 July 2025: selling the share within 4 years would attract SSD of up to 16% of the share's value.
- If Joy's income were lower: at S$10,000 a month, her TDSR limit would be S$5,500 a month, about S$991,400 over 23 years, so she would need more of her own funds.
What to check for your own situation
- Purpose and facts: whether the transfer is a genuine change of ownership at market value, and how IRAS might view it under section 33A. Get advice from a lawyer before you start.
- Stamp duty: BSD on the share, any ABSD on the buying spouse's profile, and any SSD if you are within the holding period. Use the stamp duty calculator.
- CPF: the outgoing owner's refund amount on the CPF Home ownership dashboard.
- Financing: whether the remaining owner can borrow enough on their own income under TDSR and LTV, using the how much can I borrow calculator.
- The next purchase: the outgoing owner's own loan eligibility and cash for a new home.
Related reading: Singapore property decoupling guide and IRAS section 33A and 99-to-1 arrangements.
This simulated case study is general information, not legal or tax advice.
Frequently asked questions
What is decoupling in Singapore property?
Decoupling is when one co-owner, often a spouse, transfers their share of a property to the other co-owner so that they no longer own a residential property. It is a sale of the share, so stamp duty, CPF refunds and financing all apply.
Does the spouse buying the other's share pay ABSD?
IRAS says a Singapore citizen who owns only that one property and buys more of it from the co-owner pays no ABSD on the acquisition, but does pay Buyer's Stamp Duty. A PR in the same position is charged 30% ABSD on the share, but may qualify for IRAS's partial remission that reduces it to 5%.
What happens to the outgoing spouse's CPF?
The outgoing owner must refund to their CPF account the CPF used for the property plus accrued interest, worked out on CPF's formula for a part-share sale. Check the exact figure on your CPF Home ownership dashboard.
Can IRAS challenge a decoupling or 99-to-1 arrangement?
Yes. Under section 33A of the Stamp Duties Act, IRAS can disregard or vary an arrangement made to avoid or reduce stamp duty, claw back the duty and impose a 50% surcharge. By April 2024, IRAS had found tax avoidance in 166 of 187 '99-to-1' cases reviewed.
Is Seller's Stamp Duty payable on a share transfer?
Only if the share is sold within the SSD holding period. For property bought on or after 4 July 2025 that is up to 4 years (16%, 12%, 8%, 4%); for property bought between 11 March 2017 and 3 July 2025 it is up to 3 years (12%, 8%, 4%).