Interactive Investor reports 79% rise in ISA millionaires in one year

The number of ISA millionaires on interactive investor has risen by 79%, from 1,607 one year ago to 2,869, the platform has revealed.

The number of high net worth investors holding seven-figure accounts on the platform hit a record-high of 2,869, up from 1,607 recorded at the end of February 2025.

The firm also said its ISA millionaires’ portfolios had reported strong investment growth, returning 57% on average in the last six years.

The average age of an ISA millionaire on the platform is 72 – one year younger than in February 2025 - while around 69% of its ISA millionaires are men, with 31% women.

The firm said its millionaires typically have a mix of funds, equities, and investment trusts, but their portfolio weightings differ to the average customer portfolio.

• Investment trusts: 33% of the average portfolio for ISA millionaires vs 15% for ii’s broader ISA base
• Equities: 36% vs 33%
• Funds: 18% vs 28%
• Cash holdings: 4% vs 8%
• Exchange-traded products (ETPs): 8% vs 13%

Richard Hunter, head of markets at Interactive Investor, said: “The list of most popular holdings among ISA millionaires suggests that these investors do not stop when they hit the psychological £1 million mark, but rather keep adjusting their portfolios to reflect the changing investment landscape."