National Savings and Investments (NS&I) has increased the underlying rate for Premium Bonds to 4.35%, effective from the September draw. This marks a significant boost from the previous rate of 3.8% and the earlier 3.3% at the start of the year, returning the rate to one of its highest levels in modern history.

The adjustment comes as NS&I seeks to remain competitive in a savings market where other institutions have offered higher returns, leading some savers to move their funds elsewhere. The increased rate is intended to attract savers back to the product.

Premium Bonds, a savings product from NS&I, offer tax-free prizes ranging from £25 to £1 million, with the principal amount remaining secure. This structure, however, means there is no guaranteed return, and the likelihood of winning a significant prize is often debated.

For individuals holding the maximum eligible amount of £50,000, introduced in 2015, the increased rate means a greater potential return. Over a million people hold the maximum amount. However, for those with smaller holdings, the probability of winning a substantial prize remains low.

Some savers have expressed dissatisfaction with the prize levels and the perceived lack of wins, particularly for bonds held over many years. Conversely, others are drawn to the unique proposition of winning tax-free cash prizes without risking their initial investment. This has led to varying opinions on whether Premium Bonds are a worthwhile savings vehicle, often described as a 'marmite' product.

The recent rate increase is one of the largest boosts ever for Premium Bonds. NS&I may continue to adjust rates if it struggles to attract sufficient funds amidst competition from other savings providers. The institution has also faced scrutiny over its handling of bereaved customers' accounts and its technological infrastructure.

For many, Premium Bonds are seen as a supplementary savings option, suitable for those who have already maximized other financial instruments such as ISAs, stocks and shares, and pension contributions. They are also considered by some as a place for emergency savings due to their relatively quick access and the element of chance.

Bond bonanza: Tens of millions of us hold Premium Bonds... to a varying degree of luck