 NSI Premium Bonds offer savers the chance to win extra cash, tax-free, every month through randomly generated prize draws. However, a number of lucky bondholders might be missing out on their winnings, as there are approximately just over 2.6 million Premium Bonds prizes worth more than 88.8million collectively going unclaimed, an NSI spokesperson has said. Winners ... 2.6 million Premium Bond prizes are still going unclaimed... 