Who should compare the options?
This guide is for individuals considering a genuine transfer of a let-property interest to a partner. It assumes a personally held investment property and ordinary residential letting. Company transfers, partnerships, trusts, separation and overseas ownership need separate analysis. The SDLT discussion concerns England and Northern Ireland; Scotland uses LBTT and Wales uses LTT. Guidance checked on 5 November 2026.
First identify the current legal and beneficial owners, the interest to pass, its value and any payment or debt arrangements. Changing where rent is paid does not, by itself, establish that ownership has changed. A transfer also changes economic rights and should be assessed alongside relationship, succession and lender considerations.
CGT: a gift can be a disposal without cash proceeds
For a gift to an unmarried partner, the market-value rule in TCGA 1992 section 17 normally substitutes market value for the amount received. Being unmarried does not by itself make two people connected for CGT purposes, but a gift is still not an arm’s-length bargain. Establish a defensible valuation of the actual interest and the allowable acquisition and enhancement costs allocated to it.
TCGA 1992 section 58 generally provides no-gain/no-loss treatment for transfers between spouses or civil partners living together, subject to its conditions. This normally carries the latent gain into the recipient’s base cost rather than removing it forever. Do not extend that treatment to unmarried couples. If a loss arises under other rules, check whether it is allowable and whether any restrictions apply before promising future relief.
SDLT: no cash payment does not mean no consideration
Mortgage liability assumed as part of a transfer can constitute chargeable consideration under Finance Act 2003 Schedule 4. Review the actual debt and transaction arrangements rather than treating the property’s net equity as the SDLT base. Cash, debt and linked arrangements all need consideration. A solicitor should confirm the legal effect and lender consent requirements.
Check rates, higher-rate conditions, residence and filing obligations for the actual completion date. Do not copy the historical numerical examples in general HMRC guidance as current rate calculations. The CGT spouse treatment is not a general SDLT exemption. The acquisition structure and the parties’ circumstances must be tested separately.
Rental income: distinguish married and unmarried joint owners
HMRC PIM1035 explains that non-partnership joint owners normally share property profits according to ownership, although a genuine agreed profit division can differ. Any tax reporting must match the arrangement actually made and implemented. Income-only arrangements and retained rights can raise wider tax questions, so a new bank instruction is not a complete planning solution.
For spouses or civil partners living together, ITA 2007 section 836 normally treats income from jointly held property as shared equally unless an exception applies. A declaration under section 837 using Form 17 can reflect actual unequal beneficial interests in both property and income. It does not create those interests or permit an arbitrary tax split. Evidence is required and HMRC must receive the declaration within 60 days of its date. Form 17 is not the route for unmarried couples.
Hypothetical comparison: three different starting figures
Assume an unmarried owner proposes to give a 40% interest in an English rental property valued at £600,000, with £250,000 outstanding borrowing. A simple pro-rata illustration gives £240,000 as the transferred share of gross value and £100,000 as 40% of the debt. The £140,000 difference is equity, not an automatic tax base.
CGT needs a valuation of the actual interest and allocated allowable costs. SDLT needs the consideration actually given, including the legal debt arrangements. Future rental tax needs the effective ownership and profit-sharing terms. These numbers demonstrate why one figure cannot answer all three questions; they are not a valuation, a liability calculation or a client case. No tax saving is assumed.
Sequence the decision before executing the transfer
Obtain ownership documents, mortgage terms, valuations and original cost evidence. Compare the transfer taxes and professional or refinancing costs with a forecast of future rental tax, including finance-cost restrictions and each person’s other income. Confirm the legal rights and lender position before the deed is signed. Then complete the legal steps, required returns and any valid Form 17 declaration, and update rental records from the effective dates.
Review estate-planning consequences and the donor’s retained benefits separately. Bespoke advice is especially valuable where borrowing is substantial, there is an imminent sale, past ownership is unclear or an income allocation differs from capital rights. UA Tax advises London and UK-wide property owners through property tax planning, property CGT advice and SDLT advice. Book a Tax Consultation or Get in Touch before committing.
For advice on your own circumstances, see our Property tax planning service and agree the scope before acting.
Official sources and further reading
These primary sources support the framework above. Check the current version before acting because tax law and HMRC guidance can change.