The UK ISA Market Is Booming: Key Insights from the latest HMRC Figures
The UK ISA market has experienced one of its strongest years on record, according to the latest HMRC ISA statistics covering the performance of the market in the 2023/24 tax year. With interest rates at multi‑year highs and savers seeking tax‑efficient returns, both Cash ISAs and Stocks & Shares ISAs saw significant changes in behaviour throughout the 2023/24 tax year. Below, we break down the most important trends shaping the ISA market in the UK today.
Adult ISA Subscriptions in 2023/24 Grow to 15 Million
HMRC reports show that around 15 million Adult ISA accounts were subscribed to in 2023/24, up from 12.4 million in the previous year. One of the most substantial increases in a decade, reflecting a clear resurgence in ISA usage, boosted particularly by the improving attractiveness of cash returns.
This shift could be a key indicator of confidence returning to the UK savings market, with savers once again leveraging ISAs for tax‑free income and long‑term planning.
Total ISA Subscriptions Hit £103 Billion
Total subscriptions to Adult ISAs hit £103 billion in the 2023/24 tax year, representing a £31.4 billion year‑on‑year increase. Cash ISAs were the standout performer, jumping 67% year‑on‑year (equivalent to an additional £27.9bn). Stocks & Shares ISAs also saw positive momentum, rising 10.9%, with Lifetime ISAs also growing by 25.3%.
This surge ties directly to competitive rates, with many providers offering some of the highest Cash ISA interest deals in over a decade.
Cash ISA Growth in 2023/24
Multiple analyses confirm that Cash ISAs regained dominance in 2023/24:
- Over 2 million people opened a Cash ISA, nearly ten times more than Stocks & Shares ISA openers, according to Trustnet.
- Nearly 10 million people now hold a Cash ISA, more than double the number holding a Stocks & Shares ISA.
- Consumers placed £69.5bn into cash vs £31.1bn into investment ISAs, a clear sign of risk‑averse behaviour.
HMRC also notes that Cash ISAs now represent 66% of all ISA subscriptions, underlining a major swing back toward guaranteed returns. With fixed‑rate deals averaging 3.84% to 4.6%, savers were able to lock in returns that outpaced many easy‑access and standard savings accounts.
Stocks & Shares ISAs Maintain Long‑Term Strength
Although cash captured the headlines, Stocks & Shares ISAs still hold the majority of long‑term value:
- They account for 58.6% of total ISA market value, with cash at 41.3%.
- The market value of Stocks & Shares ISA holdings rose 18.7% year‑on‑year, supported by market rebounds and increased investor contributions.
This could highlight a split market: savers choosing security in cash, while long‑term investors keep faith in equities.
Total ISA Market Value Climbs to £872 Billion
A standout figure from the latest HMRC release is the total market value of ISA holdings, which rose to £872 billion at the end of 2023/24 a 20.1% increase.
This represents one of the ISA market’s largest annual expansions and reflects both rising contributions and improving investment valuations.
Junior ISAs Continue Their Steady Rise
The Junior ISA (JISA) market also saw:
- 1.37 million JISAs subscribed to, up from 1.25m.
- £1.8 billion in contributions.
- An average subscription rising 10.4% to £1,347.
Parents and guardians continue to prioritise long‑term savings for children, with consistent year‑on‑year growth.
Why the ISA Landscape Has Shifted
Three potential factors that could explain 2023/24s dramatic ISA movement:
1. Higher Interest Rates Drive Cash Uptake
Competitive fixed‑rate ISAs, some exceeding 4.5%, made Cash ISAs significantly more attractive.
2. Economic Uncertainty Encourages Low‑Risk Saving
Inflation volatility and slowing growth prompted savers to seek stability.
3. Increased Market Visibility and Digital Access
Digital‑first banks and investment apps continue to widen ISA participation and simplify engagement.
What Could be Next for the UK ISA Market?
Experts anticipate that the next HMRC release (for 2024/25) may show even higher Cash ISA activity, particularly if interest rates remain competitive. Trustnet suggests that 2024/25 could be another “stunning” year for cash subscriptions as savers continue to prioritise certainty.
Meanwhile, upcoming government reforms could reshape limits, transfer rules, and product categories. All of which could influence how savers choose to distribute their annual £20,000 allowance.
The information presented in this article is informed by data published recently by HMRC, alongside analysis drawn from industry reports and publicly available research.
