Form 17: splitting joint property income unequally with your spouse

Who needs it

• Married couples and civil partners who live together and own a let property, or other income-producing asset, jointly.
• Couples whose beneficial shares in the property and its income are genuinely unequal, for example 75/25 under a declaration of trust.
• Couples who want each spouse taxed on their real share instead of the 50/50 split HMRC otherwise applies.

What you need before you start

• Both spouses' or civil partners' names, addresses and National Insurance numbers or UTRs.
• Details of the property or asset and each person's share of it and of the income.
• Evidence that your beneficial interests are unequal, such as a declaration of trust or deed.
• Both signatures, and a note of the date the second of you signs, because the 60 days run from the declaration.

How to file Form 17

1. 1Check you qualify: you're married or in a civil partnership, you live together, and you own the asset as tenants in common in unequal shares. Beneficial joint tenants can't use Form 17.
2. 2Put the unequal ownership in writing first, usually with a declaration of trust, if it isn't already set out in the title.
3. 3Fill in Form 17 on GOV.UK. It can't be saved part-way, so have everything ready, and it must be fully completed before it will print.
4. 4Both of you sign and date it. It can go to either spouse's or civil partner's tax office.
5. 5Send it with the evidence so HMRC receives it within 60 days of the date of the declaration. Keep proof of when you sent it.

The 50/50 rule and when Form 17 overrides it

HMRC treats most income from property held jointly by a married couple or civil partners who live together as split equally between them, whatever their actual shares. This is the 50/50 rule in section 836 of the Income Tax Act 2007 (TSEM9842).

A valid Form 17 declaration under section 837 replaces that split with your real shares. It must be made jointly on Form 17; if one of you won't sign, the 50/50 split stays. HMRC's manual also lists income the 50/50 rule doesn't apply to in the first place, such as partnership income and income from jointly held shares in a close company (TSEM9814).

Your shares must be real

HMRC's manual says the declaration must state your actual beneficial interests, and your share of the income must match your share of the property (TSEM9850). You can't make a declaration where you own the property as beneficial joint tenants.

With a let property, the usual way to create unequal shares is a declaration of trust or a transfer of part of the property. That has legal and possibly Capital Gains Tax and LBTT or SDLT consequences, so take advice before changing ownership.

The 60-day limit and when it takes effect

The declaration takes effect from the date the last of you signs it, provided HMRC receives the notice within 60 days of that date (TSEM9860). HMRC's manual says there is no power to extend the time limit (TSEM9862).

Only income arising after the date of the declaration is covered. A declaration that arrives late has no effect, and you'd need to make and send a fresh one within 60 days.

How long it lasts

A declaration keeps applying until one of you dies, you separate permanently, you divorce or dissolve the civil partnership, or either person's beneficial interest in the property or its income changes (TSEM9864). After that, the 50/50 rule applies again unless you make a new declaration.

You can make a different choice for each asset, and you don't have to make a declaration as soon as you acquire one. Each of you then reports your own share of the rent on your Self Assessment return.

Common mistakes

• Sending it late. HMRC's manual says a late declaration has no effect at all, and there's no power to extend the 60 days. You'd have to make a new declaration.
• Using it to choose a split that doesn't match ownership. The declaration must reflect your real beneficial interests in both the property and the income.
• Owning the property as beneficial joint tenants. A Form 17 declaration can't be made then; the ownership has to change first.
• Expecting it to backdate. Only income arising after the declaration is covered.
• Forgetting it can stop. It ends on a death, a permanent separation, divorce or dissolution, or any change in either person's beneficial interest.