Premium Bonds Prize Rate Rises to 4.35% as NS&I Sweetens the September Draw

National Savings and Investments quietly pushed through its second Premium Bonds rate rise of the year this week, and the numbers behind it are bigger than the headline suggests. From the September draw, the prize-fund rate climbs from 3.8% to 4.35% — the highest it has been since December 2024 — and the odds of any single £1 bond number winning something improve from 22,000-to-1 to 21,000-to-1. For the 22 million people already holding Premium Bonds, and for anyone weighing them up against a normal savings account this autumn, that shift changes the maths just enough to be worth a proper look. It arrives at a time when the gap between a guaranteed savings rate and a purely random prize draw has narrowed to its tightest point in almost two years, which is exactly the comparison NS&I would rather savers didn't make too closely. The government-backed bank has never had to compete this hard for deposits, and this rise is one of the clearest signs yet of how far it's prepared to go. Whether that's good news for you depends entirely on how much you already hold in bonds and what else you're doing with your spare cash — the details below matter more than the headline percentage.

What actually changes from 1 September

NS&I says the increase reflects "current market conditions" and helps it hit its net financing target — essentially the amount the Treasury wants the savings bank to raise from the public each year. It is the second rise inside three months: the rate went from 3.3% to 3.8% for the July draw after a long run of cuts stretching back to early 2024, and now jumps again for September. The prize pot itself grows by roughly £63m, from £434m to about £497m, and NS&I expects 308,000 more prizes to be paid out next month than were paid out in August. Bond numbers are entered into the draw automatically once you've held them for a full calendar month, and the winning numbers are still generated by ERNIE — NS&I's random number generator, now on its fifth version — rather than by any human picking favourites. ERNIE runs the draw overnight on the first working day of the month, and results are published on NS&I's site and app the same morning, so there's no lag between the draw and finding out whether you've won.

Crucially, the extra money isn't spread evenly. NS&I has trimmed the number of £25 consolation prizes — down from around 2.3 million to about 1.7 million — and used the savings to fatten the prizes further up the scale. The number of £100,000 wins rises from 83 to an estimated 95, £50,000 prizes go from 165 to 192, £25,000 payouts climb from 331 to 382, and £10,000 prizes go from 827 to 954. The two £1 million jackpots stay exactly where they were: two, no more, no less, every single month regardless of the prize-fund rate. You can hold bonds in £25 units up to a maximum of £50,000 per person, and the minimum first purchase is £25 as well, so the entry point hasn't moved even though the odds have. It's a deliberate design choice — NS&I wants more winners to notice a meaningful sum land in their account, rather than another £25 that barely registers.

Why now

Sarah Coles at AJ Bell put it bluntly this week: NS&I is "pulling out all the stops" to keep savers' cash from drifting to banks and building societies offering guaranteed returns closer to 5%. That competitive pressure is the real story here, not generosity. Caitlyn Eastell at Moneyfactscompare.co.uk makes a similar point — the 4.35% figure is an average across everyone who holds bonds, not a rate any individual saver is promised, and treating it as one is where most people go wrong.

Two years of cuts, now reversed

It's worth putting this rise in context, because the direction of travel has flipped hard. Through 2023 and into 2024, NS&I trimmed the prize-fund rate repeatedly as the Bank of England's own rate came down from its post-inflation peak, dragging Premium Bonds from a high of 4.65% down through a series of quarter-point cuts to just 3.3% by the start of this year. Savers who bought bonds expecting a fixed return watched the effective rate shrink every few months with no warning beyond a line on NS&I's website. This year's story is the opposite: two rises in three months, first to 3.8% then to 4.35%, have clawed back most of that lost ground in a fraction of the time it took to lose it.

The maths that catches almost everyone out

Here's the bit NS&I's press release doesn't lead with: most bond holders, even with entirely typical luck, will earn nowhere near 4.35% a year. A freedom of information request from AJ Bell earlier this year found that 62% of all Premium Bond holders have never won a single prize — not £25, not anything. Fewer than 1% of all prizes paid out between February 2025 and January 2026 went to accounts holding less than £1,000, which tells you most of the small-scale magic people imagine simply doesn't happen at that level. Larger holdings shift the odds meaningfully in your favour, since more bond numbers mean more entries into the same draw, but even someone holding the full £50,000 should expect a wide spread of outcomes from one year to the next rather than a steady 4.35%. Averaged over many bondholders and many months, the numbers even out to something close to the prize-fund rate — but no individual saver experiences the average, they experience one specific outcome, and for most people that outcome is quieter than the headline suggests. NS&I's own data backs this up: the median prize received by a winning bond in recent years has consistently sat closer to £50 than to anything approaching a meaningful annual return.

If you hold the maximum £50,000 and somehow landed exactly the average 4.35% return, that would work out at £2,175 a year, tax-free. In practice, the prize-fund rate behaves more like a lottery-adjusted average than an interest rate: some months you win nothing, occasionally you win big, and across a large enough sample the payouts settle near that headline number. With £1,000 or £2,000 sitting in bonds, you are far more likely to go an entire year winning nothing at all than to see anything resembling 4.35% back. That's not a flaw in the system — it's the entire point of a prize draw rather than an interest payment, and NS&I has never pretended otherwise.

Premium Bonds versus a normal savings account

Put the improved rate next to what's actually available on the high street and the comparison still isn't flattering. Top easy-access savings accounts are paying up to 5% right now, with a realistic minimum around 4.5% if you shop around rather than accept whatever your existing bank offers. The best easy-access cash ISA currently pays 4.56% — tax-free, guaranteed, and still ahead of the new Premium Bonds prize-fund rate. Put £1,000 in an account paying 4.5% and you know, to the penny, that you'll have earned £45 by the end of the year. Put the same £1,000 in bonds and the honest answer is: probably nothing, possibly £25, and on a very good day, considerably more.

For most savers with typical amounts and typical luck, a normal savings account or cash ISA still beats Premium Bonds — the guaranteed return outweighs a slim shot at a bigger prize. That's not a hedge; it's what the odds actually say once you strip out the marketing gloss around this week's rate rise.

Where Premium Bonds genuinely make sense

None of this means Premium Bonds are pointless — they solve a specific problem for a specific type of saver, and it's worth being precise about who that is. Every saver gets a personal savings allowance before HMRC takes a cut of interest earned outside an ISA: £1,000 a year tax-free for basic-rate taxpayers, £500 for higher-rate taxpayers, and up to £5,000 if you earn under roughly £17,570. Once you're comfortably over that threshold — say you've got £30,000 or £40,000 sitting in non-ISA savings — every extra pound of interest gets taxed, while every pound of Premium Bond winnings stays entirely yours.

Higher-rate taxpayer, ISA already full, spare cash still sitting in a taxable account? Move it into Premium Bonds this month.

If you've already used your full £20,000 ISA allowance for the tax year and you're a higher or additional-rate taxpayer earning more interest than your personal savings allowance covers, moving spare cash into bonds is a sound move given where the rate now sits. For anyone still under their ISA allowance or comfortably within their personal savings allowance, it isn't — open a cash ISA first, and only look at bonds once that £20,000 is genuinely full. There's also a looming reason this decision is about to matter more: from 6 April 2027, anyone under 65 will only be able to put £12,000 of their annual ISA allowance into cash, with the rest steered toward stocks and shares. Several analysts expect that squeeze to push a fresh wave of cautious savers toward Premium Bonds simply because there'll be nowhere else tax-free left to put the money, regardless of whether the odds actually favour them.

One thing worth checking before you top up your holding this month: unclaimed Premium Bond prizes now total more than £86m across NS&I's books, much of it sitting there because people moved house and never updated their registered address. Run your bond numbers through NS&I's prize checker after every draw — not just when you happen to remember.