National Savings & Investments (NS&I) is hiking the Premium Bond prize fund rate from 3.3% to 3.7% in the July draw - the highest rate in 15 years.
The change means there will now be an extra £39million in prizes available to be won each month by bondholders.
The move means there are 320,000 more chances of winning prizes worth between £50 and £100 - however, the number of £25 prizes in the draw will fall.
