Section 694 of the Income Tax (Trading and Other Income) Act 2005 establishes the primary statutory foundation for Individual Savings Accounts (ISAs), granting the Treasury power to exempt income generated within these accounts from income tax. The legislation categorises the broader ISA wrapper into four main types: Cash ISAs, Stocks and Shares ISAs, Innovative Finance ISAs (IFISAs), and Lifetime ISAs.
For the 2026/27 tax year, the government maintains the maximum overall subscription limit at £20,000 across all adult ISAs. The Lifetime ISA retains its specific £4,000 annual maximum, which actively consumes part of the total £20,000 allowance.
For minors, the Junior Individual Savings Account (JISA) subscription limit remains frozen at £9,000 for the 2026/27 tax year.
Table: 2026/27 Key ISA Allowances
| Account Type | 2026/27 Subscription Limit | Notes |
|---|---|---|
| Adult ISAs (Total) | £20,000 | Combined limit across Cash, Stocks & Shares, IFISA, and LISA. |
| Lifetime ISA (LISA) | £4,000 | Counts towards the £20,000 total limit. |
| Junior ISA (JISA) | £9,000 | Standalone limit for eligible minors under 18. |
The Scrapped “British ISA”
When advising clients on UK asset allocations, professionals should note that the government officially scrapped the proposed “British ISA”. This initiative, which originally sought to provide an additional £5,000 tax-free allowance strictly for UK equities, was formally cancelled in the October 2024 Budget to prevent overcomplicating the investment market.
2026/27 Investment Eligibility Updates
Effective 6 April 2026, the Individual Savings Account (Amendment) Regulations 2026 introduce critical shifts in qualifying investments.
HMRC now permits Long Term Asset Funds (LTAFs) as qualifying investments for Stocks and Shares ISAs and Junior ISAs. Previously, LTAFs only qualified for IFISAs. The rules mandate that any LTAFs held within an IFISA prior to 6 April 2026 automatically transition to being treated as qualifying investments for a Stocks and Shares ISA.
Conversely, the government actively restricts cryptoasset exchange traded notes (cETNs) exclusively to IFISAs from 6 April 2026.
“The amendments will provide that cETNs are qualifying investment for an IFISA and remove their eligibility for stocks and shares ISAs and Junior ISAs. cETNs which were held in a stocks and shares ISA or Junior ISA prior to 6 April 2026 can remain within the account.”
Future Planning: Major 2027 ISA Reforms
While advising on the 2026/27 framework, practitioners must prepare clients for significant structural reforms taking effect on 6 April 2027.
- Restructured Allowances: The government will heavily modify the £20,000 total allowance structure. From April 2027, the Cash ISA allowance reduces to a strict £12,000 ceiling, while the remainder of the allowance will be distinctly carved out for Stocks and Shares ISAs.
- Mandatory National Insurance Numbers: To enhance HMRC compliance tracking, the Individual Savings Account and Child Trust Funds (Amendment) Regulations 2025 require individuals to provide a National Insurance number when opening or subscribing to any ISA from 6 April 2027.
- Flexible ISA Enhancements: HMRC will streamline the flexible ISA rules. Individuals who withdraw current-year subscriptions from a flexible account can resubscribe those withdrawn funds to a completely different ISA within the same tax year, without triggering anti-circumvention restrictions.
Consider researching the exact mechanical interaction between the upcoming £12,000 Cash ISA limit and existing Lifetime ISA subscription rules ahead of the 2027 transition.
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