Why low-coupon gilts can beat cash for higher and additional-rate income taxpayers

Rising rates make cash look appealing, but taxes can take a big bite, especially for higher-rate taxpayers. Low-coupon gilts offer an alternative, with more of the return coming from tax-efficient capital growth rather than taxable interest.
Richard is a Wealth Manager at Investment Quorum and provides his clients with expert financial advice on investments, pensions, estate planning, wealth protection, tax services and more.

The ongoing war in the Middle East has undoubtedly caused a ripple effect throughout global markets. Oil prices have spiked, perhaps surprising, gold prices have fallen from their January peak, and markets hang on every word (or Truth Social message) the US president says.

One impact now priced into UK markets is an expectation that interest rates will rise over the next 12 months. This of course will impact borrowers and savers alike, but how can you make the most of this change?

When interest rates are attractive, it is natural to leave surplus money in an interest‑earning bank account. The challenge for higher and additional-rate taxpayers is that bank interest is taxed as income, which can significantly reduce the net return.

A useful alternative that we often recommend at Investment Quorum is investing in low-coupon UK government gilts. These are UK government bonds where the majority of the investor’s return comes from the bonds price gradually increasing to maturity, rather than from a large interest (coupon) payment. That matters because, for UK individual investors, capital gains on gilts are generally exempt from Capital Gains Tax (CGT), while coupon interest is taxable as income.

The result is that investors can see a higher net return from their surplus cash from gilts than from standard deposit accounts. The differences are broken down below:

1) The key difference: income vs capital return

Cash in a bank account

  • The return is interest, with a bank offering terms to give a return to savers through either flexible or fixed rates.
  • Interest is taxed as savings income.
  • For higher and additional-rate taxpayers, this can create a meaningful “tax drag”.

You may benefit from reduced rates of tax via the Personal Savings Allowance (PSA), but it is limited (and for additional-rate taxpayers it is effectively nil). Once the PSA is used, interest is taxed at the individual’s marginal rate (i.e. 20%, 40% or 45%).

Low-coupon gilts

The return is typically split into:

  • A coupon, taxable as income.
  • Capital uplift to redemption. The way this works is that you typically buy the gilt at a reduced market value, and over time, the value rises to 'par value' at maturity.

That means a large portion of the overall yield can be economically similar to interest but treated more favourably for tax.

2) Why this is especially relevant for 40% and 45% taxpayers

For many taxpayers, the real comparison is not ‘headline savings rate vs gilt yield’. It is instead ‘net return of cash vs net return of gilts’.

This is why low-coupon gilts often look most compelling when:

  • taxable cash rates are high, and
  • the investor is already paying 40% or 45% on marginal savings income.

3) Risk and practical considerations

Low-coupon gilts are not risk-free in every sense, but they have distinct characteristics:

  • Credit risk: UK gilts are backed by the UK     government, so credit risk is typically viewed as low relative to most other investments.
  • Market price risk: If you need to sell before maturity, the     price can be higher or lower than you paid (yields move, prices move). The yield to maturity is only "locked in" if held to maturity.
  • Liquidity: Were it needed, gilts are actively traded. In practice, proceeds are typically accessible within days, though  exact timing depends on platform dealing and settlement.
  • Charges: Platform and adviser charges (where applicable) reduce returns and should be included in any comparison.

An  example:

Based on these figures, the gilt provides an estimated net return around 3.495% p.a., versus cash around 2.5% p.a. for a higher-rate taxpayer, primarily because the bulk of the gilt’s return is not delivered as taxable income.

When low-coupon gilts tend to make sense?      

Low-coupon gilts can be particularly attractive when:

  • the investor is paying 40% or 45% income tax on savings interest,
  • the money may be needed within a defined time horizon that matches available gilt maturities (e.g., 2027/2028/2029 as desired),
  • and the investor can tolerate market price movement if selling early (or is comfortable holding to maturity).

They may be less suitable when:

  • the investor needs instant access with no price fluctuation risk,
  • the relevant cash interest is sheltered (e.g., within ISA / certain allowances) so the tax advantage is reduced,
  • or the investor may be forced to sell at an inconvenient time before maturity.

Bottom line

For higher and additional-rate taxpayers, the tax treatment is often the deciding factor when considering holding cash or gilts. The tax treatment will materially change the net outcome, even if the headline rates look similar.

Note: Tax treatment depends on individual circumstances and can change. Any decision should be confirmed against the investor’s tax position and the specific dealing/holding structure.