Stop Throwing Money at Your Mortgage — Gilts at 4.8% Build Wealth Your Overpayments Never Will

Overpaying your mortgage doesn't create wealth. It reduces debt. Those are different things.

When your mortgage hits zero, you have a house and no financial assets. When your gilt portfolio hits £50,000, you have a house (with a mortgage) and £50,000 in liquid, income-producing government bonds. One of these people can handle a redundancy, fund a career change, or retire early. The other has to remortgage or sell their home.

The Bank of England base rate is 3.75% and falling. The BoE has cut four times since August 2024. Mortgage rates will follow — not immediately, but the direction is clear. Your mortgage cost is a shrinking problem. But gilt yields at current levels are a closing window.

10-year gilts yield 4.8% — the highest sustained level since 2008. Five-year gilts yield 4.45%. When the BoE cuts further, new-issue gilt yields will drop. The gilts you buy today keep paying their coupon regardless. You're locking in a rate that almost certainly won't be available in 12 months.

Consider the historical context: between 2009 and 2021, 10-year gilt yields averaged below 2%. Anyone who locked in 4.8% during that window would have been considered a genius. That window is open again now — but probably not for long. For a detailed look at how gilts work and current yields, see our gilts guide.

Gilt capital gains are exempt from CGT for individuals. This is one of the most underused tax advantages in UK personal finance, and HMRC doesn't make it easy to find.

Buy a gilt below par — say at 95p — and hold to maturity. You receive 100p. That 5p gain is completely tax-free. Combined with the coupon income (taxed as savings income, with your £500-£1,000 personal savings allowance shielding most of it), gilts offer a tax-efficient return that mortgage overpayments simply can't improve upon — because overpayments don't generate returns at all.

Higher-rate taxpayers benefit even more. A 40% taxpayer with savings income above the £500 allowance pays 40% on gilt coupons but zero on capital gains. Buying a low-coupon gilt trading at a deep discount maximises the CGT-free capital gain at the expense of taxable income. For a 40% taxpayer, a gilt with a 1% coupon trading at 85p — yielding roughly 4.5% to maturity — delivers most of that return as tax-free capital gain. The effective after-tax yield could be 4%+, compared to a 5.5% mortgage overpayment saving of... 5.5%. The gap is much smaller than headline yields suggest.

Mortgage overpayments are tax-neutral. You save interest you'd otherwise pay, but you don't create any new allowance, any new asset class, or any new tax shelter. The gilt route creates all three. For a deeper dive into UK tax planning, see our tax hub.

The overpay crowd dismisses liquidity as an edge case. It isn't.

1.3 million UK homeowners saw their mortgage payments jump during the Iran conflict rate shock. Those who'd sunk every spare pound into overpayments had no buffer except remortgaging — at higher rates. Those with gilt portfolios could sell bonds on the secondary market and have cash in their account within two business days.

Gilts trade on the London Stock Exchange via any standard brokerage account. You can sell £10,000 of gilts on a Tuesday morning and have the cash by Thursday. Try getting £10,000 back from your mortgage lender on the same timeline. MoneyHelper recommends keeping 3-6 months of expenses accessible — but accessible means you can actually get to it, not that it's theoretically available if you remortgage.

The offset mortgage crowd will point out you can use offset accounts for liquidity. True — but offset mortgages typically charge higher rates than standard fixes. You're paying for the liquidity option whether you use it or not. Gilts give you liquidity for free.

For more on how gilts work and how to buy them, see our gilts guide. If you're comparing this to savings accounts, our recent debate on gilts vs cash savings covers that angle. And for platform options to buy gilts, our investing hub compares the main UK brokers.

Yes, the average 2-year fix is 5.56% today. Guardian types love this number because it makes overpaying look like a 5.56% guaranteed return.

But you won't pay 5.56% for 25 years. You'll remortgage in two years. If the BoE cuts to 3% — which swap markets price as likely by late 2027 — your next fix might be 4%. Then 3.5%. Your overpayment "return" keeps falling.

Gilts bought today at 4.8% keep paying 4.8% until they mature. In a falling-rate environment, that locked-in yield becomes increasingly valuable. Your gilt portfolio appreciates in price (you could sell at a premium) while your mortgage rate drops (making overpaying less impactful).

By 2028, you could be paying 4% on your mortgage while earning 4.8% from gilts. That's the right side of the spread — and you get there by doing nothing except holding your bonds. The Bank of England's monetary policy page publishes the MPC minutes and forward guidance that drive these expectations.

Today's ceasefire between the US and Iran — which sent oil from over $100 to $93 — could accelerate the rate-cutting timeline. If energy prices normalise, the BoE has room to cut faster, pushing mortgage rates down sooner. Your fixed-rate gilt coupon stays exactly where it is.

They're right that debt reduction is psychologically powerful. Being mortgage-free is a genuine life goal and nobody should dismiss it.

But they're wrong that it's the optimal financial decision for most people in 2026. The optimal decision depends on the spread between your mortgage rate and available risk-free yields, your tax position, your need for liquidity, and your time horizon.

If you're on a tracker at 4.25% and gilts yield 4.8%, buy gilts. You're earning more, tax-efficiently, with full liquidity.

If you're on a 5.5% fix with two years left, overpay modestly (stay within the 10% limit), but also start building a gilt ladder for when you remortgage at a lower rate. Don't go all-in on either strategy.

If you're a higher-rate taxpayer, the CGT exemption on gilts makes the break-even mortgage rate even lower. A gilt yielding 4.8% with a tax-free capital gain component might effectively return 5.2%+ after tax, narrowing the gap with a 5.5% mortgage to almost nothing.

The right answer isn't mortgage OR gilts. It's mortgage AND gilts, weighted toward gilts while yields stay historically elevated. For a wider view on how to split your spare cash, see our savings hub and for ISA wrappers that shelter gilt income from tax entirely, see our ISA guide.

This article is for informational purposes only and does not constitute financial advice. You should seek independent financial advice before making any investment decisions.