The risks and downsides of decoupling

A saving is not the whole story

Decoupling can save a meaningful sum of Additional Buyer's Stamp Duty. But it is a restructuring of how you own your home and your mortgage, and restructurings carry risk. A sound decision weighs the saving against the risks - not just the saving. Here are the downsides to put on the other side of the scale.

1. Loan-eligibility risk

This is the big one. After decoupling, the spouse who keeps the property must hold the existing mortgage alone - and the spouse buying the next property must qualify for that loan alone, on their own income.

• If the remaining owner cannot service the existing loan on their income alone - under TDSR, at the bank's stress-test rate - decoupling does not work cleanly.
• If the buying spouse's income alone does not support the next purchase, the plan fails at the point it was meant to pay off.

Decoupling quietly assumes each spouse is individually loan-worthy for what they end up holding. Where income is uneven between spouses, that assumption can break.

2. Refinancing cost and lock-in clawbacks

The existing two-name loan must become a one-name loan. If that loan is still within a lock-in period, or within a window where legal and valuation subsidies can be clawed back, restructuring it can trigger penalties or repayments - costs that eat into the ABSD saving.

3. The cost can erode the benefit

Decoupling is not free: Buyer's Stamp Duty on the transferred share, legal fees, valuation, refinancing costs. On a high-value property the BSD on the transferred share alone can be large. A plan that looked worthwhile on the headline ABSD saving can shrink, once every cost is counted, to a thin margin.

4. Concentration of ownership

After decoupling, the home is owned by one spouse, not two. For most couples this is simply a structure. But it does mean one spouse is no longer a legal owner of the family home. In the event of a relationship breakdown, ownership being concentrated in one name is a real consideration - a matter to think through honestly, and to take legal advice on, before deciding.

5. Policy and rule-change risk

ABSD and the rules around property ownership have been revised many times. A decoupling plan is built on the rules as they stand. If rules change between planning and acting - or change in a way that affects the next purchase - the expected benefit can shrink or disappear. Decoupling is not a one-day action; over its timeline, the goalposts can move.

6. The genuineness requirement

Decoupling works only as a genuine, full transfer of ownership, properly executed and stamped. Arrangements contrived to look like a transfer without the substance of one are a different thing entirely, and the tax authority scrutinises them. Do decoupling properly, or not at all.

7. Complexity and time

Decoupling is a multi-step legal and financial project - valuation, conveyancing, stamp duty, loan restructuring - running over weeks. It is not a small administrative task, and mistakes in sequencing or qualification can be costly.

How to decide with eyes open

• Confirm, first, that each spouse independently qualifies for the loan they would end up holding. If not, stop here.
• Get the full cost quoted, and compare it honestly against the ABSD saving - with margin.
• Take legal advice on the ownership-concentration question, not just the tax question.
• Accept that rules can change, and do not build a plan that only works on a knife-edge.

The takeaway

Decoupling is a legitimate strategy, but it is a restructuring with real risks: loan-eligibility risk above all, plus refinancing costs, cost erosion, the concentration of ownership in one name, and exposure to rule changes. It is worth doing only when each spouse clearly qualifies alone, the saving clearly beats the cost, and the household is comfortable with the structure. Take advice from a conveyancing lawyer and a banker, and treat decoupling as a considered decision, not a default move.