Tax Year End Planning — 7 Things to Do Before 5 April

The UK tax year ends on 5 April. That date matters more than most investors realise — several valuable allowances reset, and opportunities that expire can’t be recovered. Here are seven things worth doing before the deadline.

1. Use your £3,000 CGT exemption

The Annual Exempt Amount can’t be carried forward. If you have unrealised gains sitting in your portfolio, consider selling enough to use the £3,000. Selling £3,000 of gains tax-free every year is much better than letting them accumulate and paying CGT on a lump sum later.

As the MHA Insights report on CGT 2026 notes, “it may be beneficial for tax purposes to realise gains each year to the extent of the annual allowance.” It’s the simplest CGT planning move there is.

If you’re married, your spouse has their own £3,000 exemption. Consider transferring assets to your spouse before selling — that’s £6,000 of gains tax-free between you.

2. Harvest losses

If you hold investments that are underwater, selling them before 5 April creates allowable losses that offset gains. This is straightforward — but watch the 30-day bed and breakfast rule. If you rebuy the same shares within 30 days, the loss gets matched to the new purchase rather than being usable.

Sell the losing position, then either wait 31 days to rebuy, or buy a similar (but not identical) fund immediately. Sold a FTSE 100 tracker? Buy a FTSE All-Share tracker instead. Different securities — no 30-day match.

3. Max out your ISA

The £20,000 ISA allowance resets on 6 April. Unused allowance is gone forever. According to HMRC’s ISA rules, you can’t carry unused allowance forward.

If you have cash sitting in a GIA or bank account, get it into the ISA before the deadline. If you have investments in a GIA with modest gains, a bed and ISA — sell in GIA, repurchase in ISA — shelters future growth permanently. See our ISA vs GIA comparison for why this matters.

4. Transfer assets to your spouse

Transfers between spouses are at “no gain, no loss” under TCGA 1992 s.58. If your spouse is in a lower tax band or has unused exemption, transferring assets before selling can save real money.

A higher-rate taxpayer transferring shares to a basic-rate spouse saves 6 percentage points on CGT (24% vs 18%). On a £10,000 gain, that’s £600.

5. Check your reporting obligation

Do you need to file SA108? If your total disposal proceeds exceed £12,000 or gains exceed £3,000, yes — even if no tax is due. Missing the reporting threshold is one of the most common causes of HMRC enquiries for retail investors.

6. Report losses before the four-year deadline

Capital losses must be claimed within four years of the end of the tax year they occurred in. If you had losses in 2021/22, the deadline to report them is 5 April 2026. After that, they’re gone forever.

Check whether you have any unreported losses from previous years. Even if they’re small, they can offset future gains indefinitely once claimed.

7. Run the numbers before you trade

Don’t guess. Upload your broker CSVs to TaxBull to see exactly where you stand — total gains, total losses, and how close you are to the reporting threshold. Use the sell simulator to model “what if” scenarios before making any trades.

Five minutes of calculation now can save hundreds in unnecessary tax — or prevent the regret of realising you should have sold that loss-maker before 5 April.

Tax planning strategies depend on your individual circumstances. Consult a qualified financial adviser or tax professional before acting. The information above reflects rules for the 2025/26 tax year.