Premium Bonds are entered into the monthly prize draw. Today, the winners of the October 2019 draw have been revealed. This month, two lucky winners have been selected for a £1 million pay out each. NS&I estimated that in total, there was a total of more than 3.3 million prizes in October, which came to a total value of more than £96 million.
For each £1 invested, NS&I give savers one unique Bond number.
Each number has a separate and equal chance of winning a prize each month.
The random number generator ERNIE (Electronic Random Number Indicator Equipment) generates numbers at random.
NS&I explain they then match those numbers against eligible Bond numbers in order to determine the winners.
Each £1 Bond number has the exact same chance of winning, with the odds being 24,500 to one for each number.
When it comes to prizes, NS&I split them into three value bands – which are higher, medium, and lower – and then allocate a percentage share of the monthly prize fund to each band.
Each month, NS&I pay out two lots of £1 million jackpots.
The balance of the prize fund allocated to the higher value band is then divided equally among the remaining prize values.
NS&I explain that first, the number of £100,000 prizes are worked out.
When the balance is less than half of that prize value, it’s then carried over to the share for the £50,000 prizes.
In the case that there’s a balance that’s at least half of the prize value, NS&I award an additional prize of £100,000 by taking a shortfall from the share for the £50,000 prizes.
They then calculate the numbers of other prizes in this value band in the same way, from highest value to lowest value.
When it comes to £5,000, any surplus or shortfall is added to or taken from the medium value band.
This middle band is calculated so there is one £1,000 prize for every three £500 prizes, and any surplus is added to the share allocated to the lower value band.
In the final band, the number of prizes are worked out so there are an equal number of £100 and £50 prizes, and that the total number of prizes of all values (including £25 prizes) are equal to the number of eligible £1 Bond units divided by the odds.