Data shows ISA super-savers up 105% in two years, as sub-£5k saving falls by a third

New analysis from Nottingham Building Society reveals a sharp rise of 105% in higher-value Cash ISA saving in the past two financial years, with more customers contributing close to the annual ISA allowance and total ISA money added increasing year on year.  

The findings are published at the start of UK Savings Week (21–27th September) and as the annual Cash ISA subscription limit for people under 65 is due to reduce to £12,000 from 6 April 2027. The overall ISA subscription limit will remain £20,000. 

The data shows that the number of members contributing £15,000 to £20,000 into their Cash ISA product more than doubled over the last two financial years, and this group of savers now accounts for nearly two-thirds (65%) of all ISA subscriptions in the latest year.  

Over the same period, the number of members contributing less than £5,000 fell by almost a third (30.6%).  

The data suggests that this growth is being driven not by new savers entering the market, but by existing customers contributing significantly more, with like-for-like new ISA money increasing 24%. Meanwhile, average deposits were higher in every comparable month from May onwards, with an average of a 19% increase year-on-year, suggesting that the savings gap is not a one-off trend. 

The savings base has deepened alongside this, with funded ISA balances increasing 19% from March 2025 to March 2026, while funded customers rose 12%. 

Nottingham Building Society also commissioned new consumer research which reveals that on a national level, many people lack confidence and knowledge around how cash ISAs products work.  

Nearly half (45%) of consumers say they do not clearly understand ISAs and home-saving schemes, while 29% believe there are too many ISA products, 28% are unsure where to find reliable information and 27% feel the rules change too often. Among younger consumers, 40% of 18-24-year-olds say they do not know where to access reliable and unbiased information about ISAs or home-buying schemes. 

Commenting on the figures, Harriet Guevara, Chief Savings Officer at Nottingham Building Society, said: “These figures show just how important Cash ISAs remain for many savers. It is encouraging to see more people making full use of their allowance, but the wider picture is more mixed. While some customers are saving significantly more, our research also shows that many people still lack confidence and clarity around what should be a simple, tax-efficient way to save. 

“As ISA reform approaches, the debate has moved beyond whether change is coming. The priority now is making sure savers understand what it means for them in practice. Added complexity risks widening the gap between those who feel confident using products such as Cash ISAs and those who are put off from getting started at all. 

“Cash ISAs continue to play a valuable role for people who want certainty, accessibility and tax efficiency, but savers should not need to navigate unnecessary confusion to make good decisions. This UK Savings Week, we would encourage anyone who has paused their contributions, feels unsure where to start, or is trying to understand which savings option fits their goals, to take a first step and seek out clear, reliable information, particularly as the reform draws closer.”  

Methodology 

The research was conducted by Censuswide, among a sample of 2,081 UK respondents (18+). The data was collected between 04.09.2026-11.09.2026. Censuswide is a member of the Market Research Society (MRS) and the British Polling Council (BPC), and a signatory of the Global Data Quality Pledge. We adhere to the MRS Code of Conduct and ESOMAR principles.