Co-ownership, shares, and Form 17

Co-ownership lets a property's primary (creator) owner invite others to share a property and set each person's ownership share, so each co-owner reports only their portion to HMRC. You choose the ownership type and your own share when you add the property, then invite co-owners afterwards.

What co-ownership is for

If a property is owned by more than one person, each owner reports only their share of the income and expenses to HMRC. With separate property records, co-ownership in the app lets the property's primary owner record who owns what, so every owner's quarterly figures and Final Declaration reflect their portion automatically. With combined My portfolio records there is no property percentage to apply, so each amount must already be the selected owner's taxable share and is never split again. That suits an owner whose co-owners handle their tax elsewhere, while co-owners who both file through this app are better served by separate property records, where amounts are recorded once and each owner's share flows to their own figures automatically. The app also captures the spouse or civil partner relationship and Form 17 status, because those change how a couple's share is treated for tax.

The primary owner is the person who created the property. Only the primary owner can invite co-owners or change ownership.

Setting ownership: you can start as sole owner and invite later

When you add a property you choose whether it is sole or co-owned and set your own ownership percentage. You do not have to decide co-ownership up front: it is fine to add the property as a sole owner at 100%, then invite co-owners later. Each owner reports the share they held on the date of each transaction, so when you invite someone you set the share they take and when it starts. The app does not automatically reduce your own share to make room, and it does not force the percentages to add up to 100%, though it shows a reminder if they do not. You can change ownership shares later from the Ownership area (changes pause only while an HMRC submission is in progress). See Add your first property for the full add walkthrough.

Where co-ownership lives, and who can use it

Inviting co-owners and editing shares live in the Ownership area (MTD Lite includes them; a plan without them shows the invite form in a locked state with the upgrade route). Accepting an invite happens from the emailed link.

Invite a co-owner

The primary owner invites from the Ownership editor:

1. Open the property and click Manage Ownership. As the primary owner you are taken to the Ownership editor (/ownership/edit), titled "Who owns what."
2. Add the co-owner's Email (required). Optionally add their Name.
3. Choose the Relationship: Spouse / Civil Partner or Other (partner, family, etc.).
4. Set the Ownership %. This is auto-set to 50 and locked for a spouse or civil partner without Form 17, and for joint tenants.
5. Choose when their ownership starts: from today, from the property's purchase date, or a custom date.
6. Click Review & apply, then confirm.

The co-owner receives an email with a secure link that is valid for 7 days. A property can have up to 10 co-owners, counting both active co-owners and any pending invites.

Note: If inviting is not included in your plan, the property's Manage owners page shows the invite form in a locked "Subscribe to a plan" state. See Plans and pricing.

Accept an invite

If someone has invited you:

1. Open the invite link from the email, or the pending-invite prompt in the app.
2. Sign in (or sign up) using the exact email address the invite was sent to.
3. Click Accept.

You are then added to the property at your declared percentage, and the property is marked as jointly owned. If accepting would take you past what your plan holds, the app shows the upgrade route instead.

If you previously left this property and are being invited back, your new ownership cannot start before the day you left, whatever start the invite carries; the months you held before leaving still count for you.

Tip: If you already added the same property to your own account and it has no HMRC submissions yet, accepting an invite for that address merges the two automatically, so you do not end up with a duplicate.

If you keep combined portfolio records and have already confirmed that every My portfolio amount is your own share, accepting another ownership-stake invite leaves that preference unchanged. Otherwise acceptance switches you to separate property records and keeps every existing entry; you can choose combined records again in Settings after confirming the own-share convention. A 0% accountant/editor invite does not change the preference or ownership declaration.

Spouse and civil partner co-owners, and Form 17

When you mark a co-owner as Spouse / Civil Partner, the app applies a 50/50 split for HMRC by default, whatever percentage is stored. To use unequal shares, a married couple or civil partners file Form 17 (Declaration of Beneficial Interests in Joint Property and Income) with HMRC, then turn Form 17 on in the app.

In the app, Form 17 is a simple on/off switch for the couple: on means your declared shares are used, off means the 50/50 default. Turning it on or off applies to both of you. The app does not ask for signing dates or signatures and does not check HMRC's rules for the declaration (for example the 60-day time limit for sending it to HMRC): whether your declaration is valid is between you and HMRC.

Whether the 50/50 rule or Form 17 applies to your situation is a tax-law question. File Form 17 with HMRC yourself, and check the rules and timing with HMRC or your accountant. The app records your status and resolves the split accordingly: it does not give tax advice.

Edit shares later

The Ownership area also gives you a portfolio-wide view. Open it to see a matrix of who owns what across your properties ("Who owns what."), then use the editor to adjust percentages, add invitees, and revoke pending invites, all confirmed with a single "Review & apply" step. The matrix and editor live at /ownership and /ownership/edit. MTD Lite includes editing shares and inviting; a plan without them shows the locked state.

When a changed share applies

The app attributes every transaction by the share you held on its date, so the date you give a change decides which transactions it reaches:

• From today, or a custom date (the "Ownership starts" control in the editor): the old split applies to transactions before that date and the new split from it. Use this for a genuine change, such as a transfer of equity.
• From each purchase date: a correction. The new split applies to the whole of your current ownership period, including transactions already recorded.
• The share slider on a property's edit page has no date control, so a change there is always a correction of the current period. Turning Form 17 on or off there is also a correction of the current period, for both of you. To have the declared split apply from a particular date instead (the 50/50 split before it, your shares from it), use Owner settings in the Ownership area, which has an optional "Applies from" date.
• Removing a co-owner (or a co-owner leaving) takes effect on the date chosen in that dialog: they keep their share of everything up to the day before, and the remaining owners' new shares apply from that day. A change part-way through a quarter is split between the two periods in that quarter's update.

Because quarterly updates are cumulative, a change or correction is picked up by your next update; see How cumulative updates work, and fixing mistakes.

If something goes wrong

• "Subscribe to a plan to invite co-owners" when you try to invite. Your current plan does not include inviting. Follow the prompt to subscribe to MTD Lite.
• An upgrade prompt when you try to accept. Accepting the invite would take you past your current plan's allowance. Follow the prompt to subscribe to MTD Lite, or remove an existing income source first.
• The invite percentage will not change from 50%. The co-owner is a spouse or civil partner without Form 17, or held as joint tenants, so a 50/50 split is forced. For unequal shares, set the relationship to Spouse / Civil Partner, file Form 17 with HMRC, then turn Form 17 on. Joint tenants stay 50/50.
• "This invite was sent to a different email address." Sign in with the exact email the invite was sent to, then reopen the link.
• "This invite has expired." Invites last 7 days. Ask the primary owner to send a new one from the Ownership editor (Manage Ownership on the property).
• An invitee is blocked on accepting. The invite would take them past their current plan's allowance. They can subscribe to MTD Lite or remove an existing income source first.
• "Only the primary property owner can ..." Inviting, removing, transferring, and revoking are restricted to the primary (creator) owner. Ask them to act, or have them transfer the primary role first.
• "Cannot change ownership while an HMRC submission is in progress." Wait for the in-flight submission to finish, then retry the change.

Important: Get your shares right before you submit. If you correct a co-owner's ownership later, see Edit or delete a property and check your figures on the Reconciliation screen.

Frequently asked questions

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