Changes will come into action from August 1st, National Savings & Investments (NS&I), the Government organisation behind the bonds, confirmed today.
Lower chances of winning
As the overall prize fund is being reduced, there will be a smaller chance of winning on the Premium Bonds.
In July, the total value of the tax-free prizes was £57,099,325 and this is predicted to fall to £49,321,500 in August.
When looking at the number of prizes, the total amount will drop to 1,751,061, from 1,903,314.
NS&I says the change is happening because of falling interest rates across the board. These have led to an increase in demand for the bonds and has put NS&I in danger of taking in more money than it needs to support the government's borrowing.
Last month NS&I also dropped the interest rate on its Income Bonds, Direct Saver and Direct ISA - a move that will come into force next month.
Value of prizes
Premium Bonds are split up into different amounts, and from August these will change as the overall fund falls.
The table below is a prediction of how the amount of prizes will fall.
Falling savings rates
Savings rates have been falling steadily this year, mainly thanks to the Government's Funding for Lending Scheme (FLS). This has given lenders cheap access to Government funding which means they don't have to rely on money from savers. There are now no accounts which beat the current rate of inflation.
Premium Bonds provide an alternative way to create some extra income and are popular among savers. But as they don't pay interest, there is no guarantee you'll earn anything extra and as the pot decreases, there's even less chance of winning.
Looking for somewhere to stash your money? Check the latest savings rates
Alternative ways to earn interest
One alternative which has been growing in popularity this year is peer-to-peer lending. This is a relatively new concept whereby individuals lend to each other and cut out the middle man – the bank.
Companies such as Zopa and Rate Setter have seen huge increases in customer numbers as savers take advantage of the increased interest rates on offer.
They work by giving the borrower a cheaper way to lend and the lender an opportunity to earn interest rates of around 5% - far higher than any standard account is offering.
However, right now, peer-to-peer lenders aren't covered by the Financial Services Compensation Scheme (FSCS) which will put some people off. This protection will be implemented at some point and until then some providers, such as Rate Setter, have a back-up fund to cover any shortfalls.
Compare interest rates on peer-to-peer options