Thousands of savers were “within touching distance” of becoming ISA millionaires in 2023, according to a money app, with many likely to have now crossed this threshold to join more than 5,000 million-pound ISA holders.

Plum secured the data through a freedom of information request (FOI) to HM Revenue and Customs. HMRC has said approximately 5,070 people had ISA accounts worth £1 million-plus by April 2023.

In response to a subsequent FOI request from Plum, HMRC said 1,240 ISA holders had accounts worth £950,000 to £999,999 in the year 2022-23 and 1,530 had accounts worth £900,000 to £949,999. Some 4,700 ISA holders had accounts valued at £800,000 to £899,999.

Plum said the delay in the data and stock market performance in recent years means that numerous accounts will have broken through the seven-figure barrier, joining the 5,000-plus people who were already ISA millionaires in 2023.

Examining the HMRC data further, Plum also discovered 59,970 ISA holders were sitting on accounts worth between £500,000 and £999,999 in 2022-23.

Plum said many of these savers could be anticipated to join “millionaires’ row” within the next decade, assuming they remained invested and achieve certain levels of compounded investment growth.

Rajan Lakhani from Plum said: “Few people could ever have imagined that when the ISA launched, it would one day be creating tens of thousands of millionaires.”

Figures released in December by National Lottery operators revealed that since the National Lottery launched in 1994, more than 7,700 millionaires have been created. The National Lottery said previously that it created 365 millionaires in 2025.

‘Plan to invest’

Maike Currie, vice president of personal finance at PensionBee, said: “What these figures tell us is the power of compounding and the importance of control – you can’t plan to win the Lottery, but you can plan to invest. Not everyone will win the Lotto – most won’t.

“Likewise, not everyone will be born into wealth, marry it or receive a life-changing inheritance.

“But investing is within the reach of ordinary earners and ISA are one of the most powerful tools we have to democratise that opportunity.

“As the end of the tax year approaches, it’s a timely reminder to use your annual ISA and pension allowances. You don’t need luck – you need time, discipline and the decision to start.”

At present, savers can deposit up to £20,000 into a cash ISA, or a mixture of other ISAs, such as stocks and shares accounts. From 2027, a change by Chancellor Rachel Reeves means the cash component will be capped at £12,000, though savers can still contribute £20,000 in total.

The allowance resets at the beginning of each tax year, meaning people have until April 5, 2026, to utilise this year’s allocation.