Gilts vs Cash ISA: Which Gives a Better Return?

Cash ISAs are the comfort blanket of British saving. They pay interest, the money stays tax-free, and you can usually get at it when you need it. Gilts, loans to the UK government, feel more complicated. Yet right now the yields on offer tell an interesting story, and the tax rules add a twist that many savers miss.

Let me walk through how the two compare, and where gilts can quietly win.

What a cash ISA actually gives you

A cash ISA pays a set rate of interest, and that interest is free of income tax. No tax return, no fuss. Rates move with the Bank of England base rate, and easy-access deals can be cut at any time. Fixed-rate cash ISAs lock your money away for a term in return for a known rate.

The appeal is simplicity and protection. Up to £85,000 per bank is covered by the Financial Services Compensation Scheme. For an emergency fund, that peace of mind is hard to beat.

The catch is the rate itself. Cash ISA rates vary a lot between providers, and the headline deals often drop after a year. You have to keep shopping around to stay competitive.

What gilts are paying now

Gilts pay a fixed coupon twice a year, and they repay £100 of face value when they mature. The number that matters most is the yield to maturity, the total annual return you lock in if you buy today and hold to the end.

As of 13 October 2026, here is a snapshot across the curve:

• UK Treasury 4.125% 2027 yields 4.14%, maturing in just a few months.
• UK Treasury 4.25% 2027 yields 4.58%, maturing in a bit over a year.
• UK Treasury 4.5% 2028 yields 4.79%.
• UK Treasury 4.625% 2030 yields 4.99%.
• UK Treasury 4% 2031 yields 5.04%.

Longer gilts pay more. UK Treasury 4.75% 2035 yields 5.38%, for example. The trade-off is that longer bonds swing in price if interest rates move, so holding to maturity matters if you want the quoted return.

For a direct swap against a fixed-rate cash ISA, a short gilt is the fairest comparison. If your cash ISA pays less than 4.58%, the UK Treasury 4.25% 2027 is worth a look for money you can leave for a year.

The tax trick: low-coupon gilts

Here is the part that makes gilts special. Gilts are free from capital gains tax, the tax on profit when you sell an asset for more than you paid. That applies even outside an ISA or pension.

Gilt interest, the coupon, is still taxable as income. So the smart move for a taxpayer is a gilt with a tiny coupon trading well below £100. Most of your return then comes as a tax-free capital gain as the price climbs back to par, with only a sliver taxed as income.

Look at these low-coupon gilts:

• UK Treasury 0.125% 2028 trades at 94.76 and yields 4.33% to maturity. Almost all of that return is the price rising from 94.76 towards 100.
• UK Treasury 0.5% 2029 trades at 90.78 and yields 4.79%.
• UK Treasury 0.375% 2030 trades at 83.72 and yields 4.88%.
• UK Treasury 0.25% 2031 trades at 80.35 and yields 4.90%.

For a higher-rate taxpayer who has used up their ISA allowance, these can beat a taxed savings account hands down. The coupon is small, so the taxable slice is small. The capital gain does the heavy lifting, and it is tax-free.

A basic-rate taxpayer still benefits, though the gap is narrower. If your savings interest already sits inside the Personal Savings Allowance, a normal cash ISA may be just as good.

Putting them side by side

• Simplicity: cash ISA wins. Open it, pay in, done.
• Tax: cash ISA is tax-free inside the wrapper. Low-coupon gilts can be tax-efficient even outside one, thanks to the CGT exemption.
• Return: short gilts currently yield around 4.14% to 4.99%, which can top many cash deals.
• Access: easy-access cash ISAs let you withdraw any time. A gilt gives its quoted return only if held to maturity; sell early and the price could be higher or lower.
• Safety: both are low risk. Gilts are backed by the UK government, cash ISAs by the FSCS up to £85,000.

So which should you pick?

For an emergency fund you might touch at short notice, a cash ISA still makes sense. For money you can commit for a set period, a short gilt held to maturity can offer a known, competitive return. If you pay higher-rate tax and have filled your ISA, a low-coupon gilt like the UK Treasury 0.125% 2028 is one of the most tax-efficient homes for cash available today.

The two are not rivals so much as tools. Many investors hold both.

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This article is for general information and is not personal financial advice. Yields and prices move daily, and the figures here are a snapshot. Gilt prices can fall as well as rise, and selling before maturity may return less than you paid. Tax rules depend on your circumstances and can change. Consider speaking to a regulated adviser before investing.

Important disclaimer

This article is for information only and is not financial advice. Gilt prices and yields move daily and your capital is at risk. Always do your own research or speak to a regulated financial adviser before investing.