26 May 2026 · 4 min read
The question
You and your partner bought a home together. Your Declaration of Trust says you each own a share based on what you have contributed. Now one of you starts making extra mortgage payments. Does that shift the split?
The answer is: it depends on what your Declaration of Trust says. But the general principle in most trust deeds is yes, additional payments that reduce the mortgage balance faster do count as contributions and can shift your beneficial ownership over time.
How overpayments build equity
Your regular monthly mortgage payment covers two things: interest on the outstanding loan, and a repayment of the capital you borrowed. An overpayment goes entirely towards capital repayment. This means every pound you overpay directly increases the equity in the property.
If the property is worth £300,000 and the outstanding mortgage is £200,000, the equity is £100,000. If one of you overpays £10,000, the mortgage drops to £190,000 and the equity rises to £110,000. That extra £10,000 of equity came from one person, not both.
What your Declaration of Trust probably says
Most well-drafted Declarations of Trust for unmarried couples include a clause about additional payments. Common approaches:
- Proportional credit. The person who overpays gets credited with the full amount, shifting their share of the equity upward.
- Shared benefit. Overpayments reduce the mortgage for both parties equally, regardless of who made them. This is less common but some couples prefer it.
- Threshold-based. Small overpayments (under a set amount per year) are treated as shared. Larger amounts shift the split.
If your Declaration of Trust is silent on overpayments, speak to your solicitor before making significant additional payments. You do not want to pay an extra £20,000 and then discover it does not change your ownership position.
Keeping the record straight
Overpayments are one of the trickiest contributions to track because they do not always show up clearly on bank statements. Your regular direct debit might be £1,200 per month. If one month you pay £2,200, the extra £1,000 is an overpayment. But six years later, a bank statement just shows £2,200 to your mortgage lender. You need a contemporaneous record that says what the regular payment was and what was extra.
Log overpayments at the time you make them. Record the amount, the date, and who made the payment. If you use TrustBadger, log it as an "overpayment" category so it is distinguished from your regular monthly mortgage entries. That way, when you or your solicitor need to calculate the split, the overpayments are clearly separated from the routine.
A note on interest savings
Overpayments save interest for both of you because they reduce the outstanding balance that interest is calculated on. This benefit is shared regardless of who made the overpayment. The ownership benefit (the shift in equity) may or may not be shared, depending on your trust deed. These are two different things and your Declaration of Trust should address both.
TrustBadger keeps a timestamped, solicitor-ready record of every contribution you and your co-owner make to your shared home. 14-day free trial, no card needed. Start your trial.
