The number of “Isa millionaires” has surged to more than 4,000, according to HM Revenue & Customs (HMRC) figures.
Some 4,070 savers were sitting on Isa pots worth more than £1m, as of April 2021, according to the data, obtained following a freedom of information (FOI) request on behalf of financial services network the Openwork Partnership.
The number of Isa millionaires has nearly tripled year-on-year from 1,480 in 2019/2020, according to the HMRC figures.
The latest total is also around nine times the 450 Isa millionaires recorded in 2015/16.
According to the latest data from April 2021, the 50 top Isa investors were sitting on average pots of £8,509,000.
The average Isa millionaire pot was £1,397,000, with these savers being likely to have their money in stocks and shares.
Isas have the advantage of being ringfenced from the taxman and investors can pay in up to £20,000 annually.
Savers do have a personal allowance, meaning many people do not pay tax on savings held in various types of non-Isa accounts.
But as savings rates have increased recently, more people could find themselves tipped over that allowance. The personal savings allowance is £1,000 for basic rate taxpayers and £500 for higher rate taxpayers. The personal savings allowance covers bank and building society accounts as well as various other types of accounts.
Setul Metha, head of partnership services at the Openwork Partnership, said: “The Isa has not only created thousands of millionaires, but it has also empowered millions of ordinary investors to build a nest egg alongside their pension.”