What are Premium Bonds?
In brief: Premium Bonds are a savings product from National Savings & Investments (NS&I) where instead of earning interest, your money is entered into a monthly prize draw. Your capital is fully backed by HM Treasury — you cannot lose your original investment.
If you’re looking this up, you probably already hold Premium Bonds — most UK adults do. You might be wondering how they fit into a retirement projection, or simply want to understand what return you can realistically expect. Both are fair questions, and the answer to each starts with understanding how the prize system actually works.
Premium Bonds are bought in £1 units (minimum £25, maximum £50,000 per person). Each £1 bond is entered into a monthly prize draw run by NS&I, with prizes ranging from £25 to £1 million. Your original investment is not at risk.
How the prize system works
Each month, ERNIE (Electronic Random Number Indicator Equipment) selects winning bond numbers at random. The total amount paid out is determined by the prize fund rate — currently 3.30% (as of April 2026, variable). NS&I adjusts this rate periodically in line with broader interest rate movements.
That 3.30% figure requires a little unpicking, because it does not mean every bondholder earns 3.30%:
- The prize fund rate is the annualised return distributed across all bonds in the draw
- The vast majority of prizes are £25; a small proportion of the fund is concentrated in large prizes (£100,000 and £1 million)
- Because a handful of large prizes skew the pool, the mean return (prize fund rate) is higher than the median return — what a typical individual actually receives
- In practice, many bondholders earn less than the prize fund rate in any given year; a few earn significantly more
- There is no compound growth — prizes are paid in cash, not reinvested into bonds
This lottery structure is part of the appeal for some people. For others, it introduces more variability than a fixed-rate account would. Neither outcome is wrong — it depends on what you are trying to do with the money.
Tax treatment
Premium Bond prizes are completely tax-free under UK law. They do not count towards your Personal Savings Allowance, your dividend allowance, or any other tax threshold. This is one of the features that makes Premium Bonds distinctive compared to standard savings accounts, where interest counts as income and may be taxable once it exceeds your PSA.
For higher-rate and additional-rate taxpayers whose PSA is reduced (£500 and £0 respectively), the tax-free nature of prizes can be a meaningful difference, particularly on larger holdings.
How Premium Bonds compare to cash savings for modelling purposes
For the purposes of a retirement projection, Premium Bonds occupy the same space as other cash holdings — liquid, low-risk, not subject to capital gains tax, with a return that is broadly correlated with prevailing interest rates.
The key differences from a standard savings account are:
- Variable and unpredictable at the individual level — the prize fund rate tells you what the pool earns in aggregate, not what you personally will receive
- No interest compounding — prizes land as cash; any reinvestment requires you to buy additional bonds, subject to the £50,000 limit
- Instant-access equivalent — cashing in typically takes a few working days via NS&I, broadly comparable to easy-access savings
Whether Premium Bonds or a savings account produces a better outcome in a given scenario depends on your tax position, the current prize fund rate versus available savings rates, and how much you have invested. A projection can show you the numbers; the decision is yours to make.
How FutureClear models Premium Bonds
Premium Bonds are modelled as a cash-equivalent asset. Because prize winnings are random at the individual level, the projection applies the prize fund rate as an approximation of expected annual return — while noting that actual returns will vary, potentially significantly, from year to year.
Returns are modelled as tax-free. No income tax or Capital Gains Tax is applied to projected prize income.
Key facts at a glance
- Maximum holding: £50,000 per person
- Minimum purchase: £25
- Prize fund rate: 3.30% (as of April 2026, variable — set by NS&I)
- Tax on prizes: none
- Capital at risk: no — backed by HM Treasury
- Compounding: no — prizes paid in cash, not added to bond holding
- Liquidity: generally a few working days to cash in
These projections are for modelling purposes only. They do not constitute financial advice. Tax rules are subject to change. Please consult a qualified financial adviser before making financial decisions.