UK CGT 30-Day Rule + Strategy 2026/27
UK CGT 30-day rule 2026/27: share matching order, bed-and-ISA, spouse transfers, annual exempt amount timing and the 18%/24% rates, with a worked example.
The 30-day Bed & Breakfast rule
Introduced in 1998 (HMRC CG51560). If you sell shares and acquire shares of the same class, in the same capacity, within the following 30 days, the sale is matched against the new acquisition, not against your existing Section 104 pool. That prevents a loss being realised by selling and promptly re-buying.
Share matching order
- Same-day rule (s.105): match against acquisitions made the same day
- 30-day rule (s.106A): match against acquisitions in the 30 days FOLLOWING the disposal
- Section 104 pool: all remaining shares, at average cost
Legal CGT planning
1. Bed-and-ISA
Sell shares in a general investment account and buy the same shares inside your ISA. Shares held in an ISA are matched separately (ISA Regulations 1998 reg. 34), so the 30-day rule does not reattach the sale to the ISA purchase. The sale uses your £3,000 annual exempt amount; the ISA holding then grows free of CGT.
Worked example (illustrative prices): 1,000 shares with a pool cost of £4.50 each, now £6.00.
- Sell 1,000 in the general account: proceeds £6,000, gain £1,500
- Buy 1,000 inside the ISA at £6.00, using £6,000 of the £20,000 ISA allowance
- Gain within the £3,000 annual exempt amount (if you have no other gains): no CGT
- Future gains and dividends on the ISA holding: tax-free
2. Spouse transfer
Transfers between spouses or civil partners living together are no gain, no loss. Your spouse can then sell using their own exempt amount, so a couple has £6,000 a year between them.
3. Loss harvesting
Losses realised in a year are set against that year's gains first. To keep a position, re-buy after more than 30 days, buy inside an ISA, or buy a different security; re-buying the same shares within 30 days cancels the loss under the 30-day rule.
4. Exempt amount timing
The £3,000 exempt amount is per tax year and cannot be carried forward. Splitting a disposal across 5 April can use two years' exempt amounts.
5. Pension contributions and the CGT rate
The CGT rate depends on how much of your basic-rate band is unused. Personal pension contributions paid under relief at source extend your basic-rate band by the gross contribution, which can move more of a gain into the 18% rate.
2026/27 CGT rates
| Where the gain falls | Shares and other assets | Residential property |
|---|---|---|
| Within unused basic-rate band (£37,700 of taxable income, i.e. £50,270 gross with the Personal Allowance) | 18% | 18% |
| Above the basic-rate band | 24% | 24% |
| Annual exempt amount | £3,000 | £3,000 |
Source: GOV.UK Capital Gains Tax.
Common mistakes
- Triggering the 30-day rule unintentionally - selling and re-buying the same shares within 30 days
- Not claiming losses - a loss not claimed within 4 years of the end of the tax year can no longer be used
- Missing the 60-day property deadline - late returns attract penalties and interest
- Confusing the exempt amount with the Personal Allowance - they are separate allowances
Related pages
Frequently asked questions
What is the 30-day rule in UK CGT?
It is the "bed and breakfast" rule in section 106A TCGA 1992. If you sell shares and acquire shares of the same class, in the same capacity, within the 30 days after the sale, the sale is matched with the new purchase rather than with your existing Section 104 pool (HMRC CG51560). That stops you realising a loss by selling on Friday and re-buying on Monday. It applies to shares and securities and, by HMRC's view in CRYPTO22200, to fungible cryptoassets. It does not apply to assets that are not pooled, such as land or a single painting.
How do I crystallise a gain using the AEA legally?
Two common routes. Bed-and-ISA: sell in a general account and buy the same shares inside your ISA; ISA holdings are matched separately (ISA Regulations 1998 reg. 34(2)), so the sale is matched with your pool and the gain is realised, ideally within your £3,000 annual exempt amount. Spouse transfer: give shares to your spouse or civil partner (no gain, no loss) and let them sell using their own exempt amount. Selling and re-buying in the same account within 30 days does not work: the 30-day rule matches the sale with the re-purchase.
What is the order of share matching for CGT?
(1) Same-day rule - shares acquired on the same day as the sale (s.105). (2) 30-day rule - shares acquired in the 30 days after the sale (s.106A). (3) Section 104 pool - everything else, at average cost. Same-day takes priority, then 30-day, then the pool (HMRC CG51560).
Can I use bed-and-ISA to reset cost basis?
Yes. The sale realises the gain, which uses your £3,000 annual exempt amount and any allowable losses; the shares bought in the ISA then grow free of CGT and Income Tax. How much you can move each year is limited by your £20,000 ISA subscription allowance, and by how much gain you are willing to realise.
How does spouse transfer save CGT?
Transfers between spouses or civil partners living together are at no gain, no loss, so your spouse takes your original base cost. When they sell, they use their own £3,000 annual exempt amount and their own Income Tax band, so a couple can realise up to £6,000 of gains a year free of CGT between them.
What CGT rates apply in 2026/27?
Gains are added to your taxable income: the part that falls within your unused basic-rate band (£37,700 of taxable income) is taxed at 18% and the rest at 24%. Each individual has a £3,000 annual exempt amount. Gains reported through Self Assessment are paid by 31 January after the tax year. UK residential property sales with tax to pay are reported and paid within 60 days of completion.
Does the 30-day rule apply to swaps between funds?
Only where you re-buy shares or units of the same class in the same fund. Two different funds tracking the same index are different securities, so selling one and buying the other is not matched under the 30-day rule. Check the fund share classes carefully, and remember that the targeted anti-avoidance rule on artificial losses (TCGA s.16A) can apply to arrangements whose main purpose is a tax advantage.
How do I report capital gains for 2026/27?
Through your Self Assessment tax return (capital gains pages) for the year, filed online by 31 January 2028; or within 60 days of completion for a UK residential property sale with tax to pay, using a Capital Gains Tax on UK property account. If you do not run a business, keep your records for at least 22 months after the end of the tax year the return covers (GOV.UK).
Can I carry forward CGT losses?
Yes. A loss must be claimed within 4 years of the end of the tax year in which you made the disposal; once claimed, unused losses carry forward indefinitely. Losses brought forward are only used to bring the year's gains down to the annual exempt amount, so they are not wasted against gains the exempt amount already covers (GOV.UK).
Does the 30-day rule affect crypto?
Yes. HMRC applies the same-day rule, the 30-day rule and Section 104 pooling to fungible tokens, with a separate pool for each type of token (CRYPTO22200). Selling bitcoin and buying bitcoin back within 30 days is matched under the 30-day rule. Non-fungible tokens are not pooled.