The window to protect your money from the taxman is slamming shut, with a raft of valuable tax-free allowances resetting in weeks. Crucially, some of these breaks will be lost forever if not used by 5 April 2026, making urgent action essential for investors, savers, and anyone looking to trim their tax bill.
The Unmovable Deadline
The UK tax year concludes on 5 April 2026, a fixed date that triggers the annual reset of personal allowances. While the final self-assessment deadline for online returns for the 2025/26 year is not until 31 January 2027, and the second payment on account is due on 31 July 2026, the opportunity to maximise many tax-efficient investments and allowances expires on the April date itself. Furthermore, individuals needing to register for self-assessment for the first time for the 2025/26 year must do so by 5 October 2026.
Use It Or Lose It: The Allowances At Stake
Several core allowances operate on a strict “use it or lose it” basis, vanishing if not utilised within the tax year. The most significant is the £20,000 Individual Savings Account (ISA) allowance, which does not roll over. From April 2027, the Cash ISA allowance for those under 65 is set to be capped at £12,000, adding future impetus to current planning. The Junior ISA allowance for the year stands at £9,000.
For those in work, the £12,570 personal income tax allowance is a cornerstone, alongside the marriage allowance which permits transferring up to £1,260 of it to a spouse or civil partner, potentially saving £252. The lesser-known £1,000 annual trading allowance for miscellaneous income is also forfeited if not claimed.
Pension contributions remain one of the most powerful tools for reducing taxable income, with an annual allowance of up to £60,000 for most, and the ability to carry forward unused allowance from the previous three years. However, for those who have started drawing flexibly from their pension pot, the money purchase annual allowance of £10,000 applies.
Investment Reliefs Changing Forever
The most profound changes, however, surround venture capital and enterprise investment schemes, where generous tax reliefs are being scaled back, creating a definitive deadline for higher-rate savings.
From 6 April 2026, the income tax relief rate for investments into Venture Capital Trusts (VCTs) will be cut from 30% to 20%. This sparks a final rush to secure the current top rate. An investor using the full £200,000 annual VCT subscription limit by 5 April could see their tax liability reduced by £60,000. A £50,000 investment would yield a £15,000 saving. To qualify, investments must be held for five years, and dividends and capital gains from VCTs are tax-free.
Similarly, the Seed Enterprise Investment Scheme (SEIS) offers the most aggressive income tax relief at 50%, up to a £200,000 investment, delivering a potential £100,000 saving. SEIS also provides capital gains tax (CGT) exemption on disposals after three years, and a unique 50% CGT reinvestment relief for gains rolled into SEIS shares. Investments may also eventually qualify for inheritance tax relief.
For the larger Enterprise Investment Scheme (EIS), income tax relief remains at 30% on investments up to £1 million. Alongside VCTs and SEIS, EIS shares can benefit from a rise in Business Asset Disposal Relief (BADR), which increases the effective CGT rate from 14% to 18% for disposals on or after 6 April 2026, though the £1 million lifetime limit stays.
Capital Gains Tax planning more broadly requires attention: timing disposals of assets to straddle the tax year can defer bills, and gains on UK residential property not covered by main residence relief must be reported and paid within 60 days of completion.
Secondary Deadlines and Systemic Changes
Beyond personal tax, other deadlines loom. The VAT filing deadline for the quarter ending 31 March 2026 is 7 May 2026. For companies, corporation tax deadlines are based on their accounting period, not the tax year. A significant administrative shift occurs on 31 March 2026, when HMRC’s old online filing service for company tax returns closes; all returns must be filed using commercial software from 1 April.
From April 2026, Making Tax Digital for income tax becomes mandatory for businesses with income over £50,000, necessitating compatible software for digital record-keeping. Meanwhile, Child Benefit weekly rates will increase from 6 April 2026 to £27.05 for the eldest child and £17.90 for others, though the High Income Child Benefit Charge continues to taper the benefit away for incomes over £60,000.
With a complex landscape of allowances and imminent changes, testing your knowledge ahead of the deadline is crucial. How well do you understand the rules that could save you thousands before the tax year ends?
