UK ISA Wrapper-Mix Shift 2010-2022, PlainISA Research

The headline trend

In 2010-11, Cash ISAs accounted for approximately 65% of new ISA subscription value, with Stocks & Shares ISAs taking approximately 30%. The remaining 5% comprised assorted Junior ISA precursors and PEP/TESSA conversions still working through the legacy pipeline. By 2022-23, Cash ISAs had fallen to approximately 46% of new subscription value, while S&S ISAs had grown to approximately 47%. The Lifetime ISA and Innovative Finance ISA together took the remaining 7%.

The crossover, where S&S ISA subscription value first exceeded Cash ISA subscription value, occurred in the 2018-19 tax year. From 2018 onwards, S&S ISA share has remained ahead, with the gap widening modestly each year.

The 2016 Personal Savings Allowance inflection

The most significant policy event in the period was the introduction of the Personal Savings Allowance on 6 April 2016. The PSA gave basic-rate taxpayers £1,000 of tax-free interest income outside any ISA wrapper, £500 for higher-rate taxpayers, and £0 for additional-rate taxpayers. At Cash ISA rates prevailing in 2016-19 (typically 1-2% gross), £1,000 of tax-free interest required roughly £50,000-£100,000 of Cash ISA balance to fully utilise, well above the typical Cash ISA holding.

Practical implication: most basic-rate-taxpayer savers no longer received any tax benefit from a Cash ISA, because their non-ISA savings interest already fell under the PSA. The wrapper became attractive primarily for higher-balance savers, higher-rate taxpayers, and the inflation-protected fixed-rate Cash ISA segment.

HMRC subscription data shows Cash ISA new-account opening volumes declining materially from the 2016-17 tax year onward, even as average per-account balance rose. The wrapper became more concentrated in higher-balance, older-demographic savers.

The 2017 Lifetime ISA launch

The Lifetime ISA launched in April 2017 with the 25% government bonus and the dual first-home/retirement-age structure. Initial uptake was modest, approximately 167,000 LISA accounts opened in the first year. By 2022-23 the cumulative LISA account count reached approximately 600,000.

The LISA's £4,000 sub-limit and the £450,000 property value cap constrained adoption. Property price inflation between 2017 and 2024 pushed many target buyers (particularly in London and the South East) above the £450,000 cap, effectively excluding the wrapper from their first-home plans. Industry advocacy groups have requested cap reform; the £450,000 figure has not been revised in successive Finance Acts.

Age-cohort distribution

HMRC publishes wrapper-mix by age band. The headline pattern: Cash ISAs are increasingly concentrated in older age groups, while S&S ISAs skew younger and higher-income.

• Savers aged 65+ hold approximately 38% of total Cash ISA funds while representing under 19% of the UK adult population.
• Savers aged 25-44 hold approximately 52% of total S&S ISA new subscriptions in 2022-23, up from approximately 38% in 2010-11.
• Lifetime ISA holders are by definition aged 18-39 at opening; the median LISA subscriber age at opening is approximately 28.

Industry expectation for 2024-25

The 6 April 2024 multiple-ISA rule change is expected to drive subscription dispersion across providers, particularly in the Cash ISA segment where rate-shopping is common. HMRC has not yet published 2024-25 reconciled statistics; the full impact will be visible in the 2025-26 publication cycle.

Headline subscription totals are projected to remain broadly stable, but average per-account balance will likely decline as savers split capital across two or more providers per year. The S&S ISA share is expected to continue growing modestly, particularly as platforms compete on cost and feature breadth.

Limitations

HMRC's ISA Statistics report subscription value, not net new capital (transfers between wrappers within a year count once at the original subscription point, but cross-tax-year transfers don't recur in the headline subscription figure). Account counts include dormant or zero-balance accounts. Age-band figures are derived from a sample, not a census, so confidence intervals widen for small wrapper types.

The 2024 multiple-ISA rule introduces a new measurement challenge: a saver opening two Cash ISAs in one year now appears as two new accounts in HMRC's data, which complicates time-series comparison with the pre-2024 one-account-per-type regime.

Sources

• HMRC Individual Savings Account Statistics (annual)
• HMRC Lifetime ISA Statistics
• HMRC Personal Savings Allowance Guidance

Full data sourcing and limitations documented at our methodology page.

Related research

• The 6.25% net loss: LISA early-exit arithmetic
• Cash ISA vs Stocks & Shares ISA long-run real returns

Extended notes

The British savings landscape encompasses tax-advantaged wrappers spanning Cash ISAs, Stocks & Shares ISAs, Lifetime ISAs (LISA), Innovative Finance ISAs (IFISA), and Junior ISAs (JISA) for minors. Each operates under distinct statutory rules legislated through successive Finance Acts since the framework launched in April 1999, replacing earlier Personal Equity Plans (PEPs introduced 1986) and Tax-Exempt Special Savings Accounts (TESSAs introduced 1991). The Personal Savings Allowance (PSA) introduced in April 2016 fundamentally altered the relative attractiveness of Cash ISA wrappers for basic-rate taxpayers by exempting £1,000 of bank interest from Income Tax outside any wrapper, plus £500 for higher-rate taxpayers (additional-rate taxpayers receive zero PSA).

Beyond statutory wrapper mechanics, savers must navigate Financial Conduct Authority (FCA) regulation governing product disclosure, marketing standards, advice permissions, and complaint-resolution processes. Provider-level competition focuses on headline interest rates (Cash ISAs), platform fee structures plus fund expense ratios (S&S ISAs), withdrawal-feature differentiation (flexibility), portability mechanics (transfer-form availability), and digital onboarding speed (online-only banks versus high-street institutions).

Across the broader retirement-savings universe, ISAs sit alongside workplace pensions (auto-enrolment defaults under the Pensions Act 2008), Self-Invested Personal Pensions (SIPPs) offering broader investment flexibility, Stakeholder Pensions for low-cost employer schemes, and Defined Benefit final-salary schemes (largely closed to new accruals across the private sector but still significant in public-sector employment). Optimising allocation across the entire mix requires assessment of marginal tax rate, employer contribution matching schedules, expected retirement-age tax position, drawdown flexibility, inheritance treatment under existing law, and personal liquidity preferences during accumulation versus decumulation phases.

Historical context matters: the original 1999 ISA cap was £7,000 split between Cash (£3,000) and S&S (£4,000 max if no Cash subscription) - vastly smaller than today's £20,000. Successive Finance Acts gradually relaxed the split-cap constraint and raised the headline ceiling, with the 2014 New ISA (NISA) reforms removing the Cash sub-limit entirely and the 2017 reforms standardising at £20,000. The cap has held nominally since 2017 despite cumulative inflation of approximately 30%, meaning the real-terms allowance has eroded materially over the past decade.