ISA Millionaire Numbers Surge 52% to Record High as Top Pots Hit £12m

The number of ISA millionaires in the United Kingdom surged by 52% in a single year, reaching a record high of 7,730 according to new HM Revenue and Customs data. For fintech professionals, this dramatic rise highlights the increasing efficacy of digital investment wrappers and the massive scale of tax-efficient wealth now being managed through retail platforms.

What was announced

A Freedom of Information (FOI) request by the smart money app Plum has revealed that the number of individuals holding more than £1 million in their ISA accounts climbed from 5,070 to 7,730 during the 2023-24 tax year. This increase of 2,660 individuals marks the largest year-on-year growth since HMRC began disclosing these figures in 2016. At that time, there were only 450 ISA millionaires, representing a 1,618% increase over the last eight years.

The data provides a detailed breakdown of the wealth tiers within this group. Of the 7,730 millionaires, the vast majority—7,300 investors—hold pots valued between £1 million and £1,999,999. A further 320 individuals possess pots between £2 million and £2,999,999, while 40 hold between £3 million and £3,999,999. An elite group of 60 investors hold pots exceeding £4 million, with an average value of £7,708,000 each. The top 25 ISA investors in the country are sitting on average pots of £11,928,000, having seen a tax-free gain of £623,000 (5.5%) in just twelve months.

Collectively, UK ISA millionaires now hold more than £10 billion in tax-free wealth. HMRC previously confirmed that all ISA millionaire pots were accumulated through stocks and shares investing rather than cash savings. This trend comes as the market prepares for significant policy shifts, including the introduction of inheritance tax on pensions in April 2027 and a reduction in the annual cash ISA allowance from £20,000 to £12,000 for savers under 65.

"A jump of more than 50% in a single year is really telling. These aren’t people who suddenly saved their way to £1m. It’s the result of years of patient investing, where the growth on your growth starts doing the heavy lifting. That’s the bit people underestimate."

Will Bryant, Director of Wealth Strategy at smart money app Plum.

The companies involved

Plum is a smart money app designed to automate savings and wealth management for retail users. The company operates in the UK and European markets, providing a platform that allows users to invest in funds, diversify across thousands of companies, and select risk profiles tailored to their personal outlook. Plum focuses on lowering the barriers to entry for investing, offering low-cost access to global markets and tools like pound-cost averaging to help users manage volatility.

In the broader fintech ecosystem, Plum has positioned itself as a data-driven advocate for retail savers, frequently using FOI requests to highlight trends in UK tax policy and saving habits. To support its technical growth and scale its investment offerings, Plum recently selected Upvest to power its UK investment infrastructure. This partnership is central to Plum's ability to provide the sophisticated stocks and shares ISA products that the HMRC data suggests are essential for long-term wealth accumulation. By integrating with infrastructure providers like Upvest, Plum aims to streamline the delivery of tax-efficient investment wrappers to a broader demographic of savers.

What FF News has reported before

FF News has closely followed Plum’s efforts to uncover the impact of UK tax regulations on retail savers. In October 2026, we reported on a Plum FOI Reveals 45,000 Lifetime ISA Savers Hit With Multiple Penalties in Single Year, which detailed how thousands of savers were being penalised for withdrawing funds from their Lifetime ISAs. This highlighted the friction points in the current ISA system that Plum seeks to address through better user education and platform design.

Earlier that year, in August 2026, FF News covered a significant technical milestone for the company when Plum Selects Upvest to Power UK Investment Infrastructure in Major Expansion. This move was designed to enhance the app's investment capabilities, allowing for more robust portfolio management as the company expanded its footprint in the UK wealth management sector.

What this means

The explosion in ISA millionaire numbers signals a fundamental shift in the UK wealth landscape, moving away from traditional pension-led retirement planning toward tax-efficient investment wrappers. As inheritance tax is set to be applied to pensions in 2027, the ISA’s status as a tax-free vehicle for spouses and civil partners makes it an increasingly vital tool for estate planning. This trend puts significant pressure on legacy wealth managers to lower their fees and improve digital accessibility, as retail platforms prove they can facilitate massive capital growth. The industry now faces a critical question: how to maintain this momentum if the government continues to tighten allowances on cash savings and reform the wider ISA framework.