Cash ISA subscriptions rose by 67% to £69.5bn in the 2023/24 tax year, according to new figures released today by HMRC.

The number of people subscribing to Cash ISAs rose 26% to 9.9m (2022/23: 7.8m).

HMRC attributed the large increase in Cash ISA subscriptions to the Bank of England bank rate and the interest swap rates which were at the highest during the 2023/24 tax year.

Britons paid £103bn into 15m Adult ISA accounts in the 2023/24 tax year (2022/23: £72 paid into 12.4m accounts), according to HMRC. The number of savers holding ISA accounts was at its highest level since 2010/11 when 15.2m accounts were subscribed to.

Stocks and Shares ISA subscriptions rose 11% (£3.1bn) to £31bn. The number of subscribers increased 7% with 283,000 new accounts opened.

Sarah Coles, head of personal finance at Hargreaves Lansdown, said she expects the gap between Cash and Stocks and Shares ISA subscriptions to close slightly during the current tax year.

She said: “Stocks and shares ISAs gained some ground after falling back a little last year, as investors realised the long-term growth potential of investment has the potential to deliver impressive returns, long after short-term spikes in savings rates are a distant memory. More recent figures show that in the first 6 months of 2025, HL saw more money transferred from cash in banks and building societies into the HL stocks and shares ISA than the whole of 2024.”

Lifetime ISA subscriptions rose 26% to £2.35bn, the highest sum put into LISAs since they were launched in the 2017/18 tax year.

Rachael Griffin, tax and financial planning expert at Quilter, said today’s figures highlight that the LISA needs reform.

She said: “The Lifetime ISA data reinforces the need for reform. Over 87,000 first-time buyers used their LISA to purchase a property in 2024/25, but at the same time 129,200 people were forced into unauthorised withdrawals, losing an eye-watering £102 million in charges. That is up from £75 million the year before and almost twenty times the level seen in the product’s early years.

“These are not reckless savers but people under financial pressure, penalised by a 25% charge that strips away not just the government bonus but part of their own contributions too.”

Junior ISAs saw £1.8bn paid in during the tax year, around 36% of which was in cash. The average subscription in 2023 to 2024 increased to £1,347, an increase of 10.4% on the 2022 to 2023 figure.

The market value of all adult ISA holdings stood at £872bn at the end of the 2023/24 tax year, a 20% increase year in year and in line with the increase in subscriptions.

There was a 22.3% increase in the market value of funds held in Cash ISAs, and 18.7% increase for Stocks and Shares ISAs.

Cash ISAs accounted for 41.3% of the market value, an increase from 40% in 2022 to 2023. Meanwhile, Stocks and shares ISA holdings accounted for 58% of the market value of ISA funds, a decrease from 59% in 2022 to 2023.

The median ISA holder (by income) had annual income of between £20,000 and £29,999. The average ISA market value of this income group was £31,536, representing a 2% increase in comparison to 2021 to 2022.

For ISA holders with incomes of £150,000 or more, the average market value was £94,894.

Claire Trott, head of advice at St James’s Place, said the figures are a reminder that Britons are not investing enough.

She said: “Today’s HMRC figures are the latest indication that the UK population is over-saved and under-invested. While a cash buffer is important – and no doubt brings comfort to savers, promising safe, guaranteed returns - individuals who chose a Cash ISA over a Stocks and Shares ISA could be missing out on hundreds of thousands of pounds over the long term.”