Premium bond winners in September 2021: are prizes ever guaranteed?

Two lucky premium bond holders have won £1m each in NS&I's September prize draw.

The jackpot winners are from Bristol and Shropshire, while five other winners received the next-best prize of £100,000.

Here, Which? reveals the winning premium bond numbers, and looks at how much you'd need to invest to 'guarantee' winning a prize.

September 2021 premium bond prize winners

This month, the two £1m jackpot prizes went to premium bond holders in Bristol and Shropshire.

The winner from Bristol is a woman who bought her winning bond (084FM963618) in October 2003, as part of a £30,000 holding.

A man from Shropshire won the second jackpot prize. His winning bond (116WA622775) was purchased in October 2006, also part of a £30,000 holding.

• Find out more:premium bonds - are they worth it?

How many winners were drawn in September?

There were 3,257,945 premium bond prizes given out in the September draw, worth a total of £93,665,875. Of these, 3,250,255 were worth £100 or less.

_{Source: NS&I}

How much do you need to save to win a premium bonds prize?

Every £1 premium bond has the same chance of being picked to win a prize. Each month, NS&I's random number generator called ERNIE (Electric Random Number Indicator Equipment), picks out all of the premium bond winners, and no number has an advantage over any other.

But, of course, you're far more likely to be picked for a prize if you have 50,000 numbers in the draw, versus just 100, for instance.

According to the tool at premiumbondscalculator.com, someone with 'average luck' and £2,000 invested in premium bonds would have a 50.1% chance of winning £25 over the course of a year.

Having average luck and £10,000 invested means you could expect to win £75 over the course of a year, with a 96.9% chance of winning at least £25.

The tool gives a virtual certainty to a win of £100 over the course of a year for anyone with the maximum £50,000 invested. With average luck, you could pocket up to £450.

If you have your eyes on the £1m jackpot prize? Don't hold your breath - even if you invest the full £50,000. The chance of becoming a premium bonds millionaire with average luck is just 0.00121%.

It's worth noting that the notion of 'average luck' includes those who are far luckier than average (including the £1m jackpot winners), as well as those whose luck is far less than average. These premium bond holders, of which there are thousands, may win nothing at all over the course of a year, even with the maximum £50,000 holding.

Find out more:what is National Savings & Investments?

The smallest holdings that have won the jackpot

While your chances of winning a prize increase the more you save and the longer you save it for, each £1 bond has exactly the same chance of being drawn as any other. This means you can win big with a small amount of savings - and even if you haven't held premium bonds for very long.

This was made evident last month, as one of the jackpot winners in the August draw had a total holding of £1,001 which was only bought just over a year before in July 2020.

But the jackpot has been won with far less. In March 2020, a man from Cambridgeshire won £1m despite only having a premium bonds holding of £25, which he'd purchased less than two years earlier in July 2018. January 2015 saw a woman from Leeds win the jackpot with a total holding of £400 - she'd been invested since August 2008.