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. 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. It 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 their own current declared share, so when you invite someone you set the share they take. 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 is part of MTD Lite and lives in the Ownership area. Accepting an invite that someone else sends you is different: it is allowed on the Free plan, within your single income-source limit.

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: Inviting is an MTD Lite feature. On the Free 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. Accepting one invite is allowed even on the Free plan, provided it stays within your single income-source limit (each co-owned property counts as one source).

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.

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 only valid for owners held as tenants in common, not joint tenants;
• requires you to confirm that both parties have signed before you can save it as filed;
• shows a non-blocking warning if more than 60 days have passed since the signing date, because HMRC may not accept a late declaration.

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. Editing shares and inviting need MTD Lite.

If something goes wrong

• "Subscribe to a plan to invite co-owners" when you try to invite. Inviting needs MTD Lite. Upgrade in Settings, or, if you only need to accept one invite, do that on Free within your single-source limit.
• 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, ensure the tenure is tenants in common, file Form 17 with HMRC, then turn Form 17 on. Joint tenants stay 50/50.
• "Form 17 requires both spouses or civil partners to sign." Tick the confirmation that both parties have signed before saving Form 17 as filed.
• A warning that the Form 17 declaration may not be accepted. More than 60 days have passed since the signing date. This is a warning only and the save still succeeds, but you may need to re-sign and re-file with HMRC.
• "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).
• A free-tier invitee is blocked on accepting. The Free plan covers one income source in total, and a co-owned property counts as one. Upgrade to MTD Lite for unlimited sources, or free up the existing 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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