United Kingdom
HM Revenue & Customs (HMRC)
Rules Implemented
Same-Day Rule (Section 105)
Disposals are first matched to acquisitions made on the same calendar day. All same-day transactions are consolidated before matching. This prevents artificial gain/loss manipulation through intra-day trading. (TCGA 1992, Section 105)
30-Day Rule (Section 106A) — Bed & Breakfasting
After same-day matching, remaining disposal quantity is matched to acquisitions in the next 30 calendar days (forward-looking only). This prevents the classic 'bed & breakfasting' strategy of selling at a loss and immediately rebuying. Earliest disposal gets priority when multiple disposals compete for the same acquisition. (TCGA 1992, Section 106A)
Section 104 Pool
Any disposal quantity not matched by same-day or 30-day rules is removed from the Section 104 pool at the pool's weighted average cost per token. The pool is a single running total per asset — all tokens of the same type are pooled together.
Annual Exempt Amount (AEA)
The first £3,000 of net capital gains per tax year is exempt from CGT (2024/25 onwards). Previously £6,000 (2023/24) and £12,300 (2022/23 and earlier). The AEA is a deduction — gains above the AEA are taxed, not the full amount.
Tax Year: April 6 – April 5
UK tax years run from April 6 to April 5. The 2025/26 tax year covers April 6, 2025 through April 5, 2026. PrivateACB displays this as '2025/26' and handles all date boundary assignments correctly.
Reports Generated
- SA108 Capital Gains Summary (HMRC boxes 13.1-13.8)
- Capital Gains Detail (per-disposal with match type breakdown)
- Section 104 Pool History (running balance per asset)
- Income Report (staking, mining, airdrops)
- Tax Audit Report (full provenance trail)
How Capital Gains Tax Works in the UK
HMRC treats cryptocurrency as a capital asset subject to Capital Gains Tax (CGT). Every disposal — selling for GBP, trading for another crypto, or using crypto to pay for goods and services — triggers a chargeable gain or loss under the Taxation of Chargeable Gains Act 1992 (TCGA 1992).
Unlike Canada (straight pooling) or the US/Australia (lot-based), the UK uses a three-tier matching hierarchy to determine which cost basis applies to each disposal:
- Same-day rule (Section 105) — match against same-day acquisitions first
- 30-day rule (Section 106A) — match against acquisitions in the next 30 days
- Section 104 pool — remaining quantity uses the pool’s weighted average cost
Example (Section 104 Pool):
| Date | Action | Quantity | Price (£) | Pool |
|---|---|---|---|---|
| 1 Jan 2025 | Buy 2.0 ETH | 2.0 | £6,000 | 2.0 ETH @ £3,000 avg |
| 1 Feb 2025 | Buy 3.0 ETH | 3.0 | £12,000 | 5.0 ETH @ £3,600 avg |
| 1 Mar 2025 | Sell 1.0 ETH | -1.0 | £5,000 | 4.0 ETH @ £3,600 avg |
Capital gain: £5,000 - (1.0 x £3,600) = £1,400
No same-day or 30-day acquisitions exist, so the disposal is matched entirely against the Section 104 pool at the weighted average cost.
The Three-Tier Matching Hierarchy
Rule 1: Same-Day Rule (Section 105)
All acquisitions and disposals on the same calendar day are consolidated before matching. If you buy 2 ETH at 9am and sell 1 ETH at 5pm on the same day, the disposal is matched to the same-day acquisition — not the pool.
Rule 2: 30-Day Rule (Section 106A — “Bed & Breakfasting”)
After same-day matching, any remaining disposal quantity is matched against acquisitions in the next 30 calendar days (forward-looking only). This prevents the classic tax avoidance strategy of selling at a loss and immediately rebuying.
The 30-day window starts the day after disposal. If you sell on January 15, acquisitions from January 16 through February 14 are matched.
Rule 3: Section 104 Pool
Whatever remains after same-day and 30-day matching is removed from the Section 104 pool at the pool’s weighted average cost per token. Acquisitions matched by the same-day or 30-day rules are diverted — they never enter the pool.
PrivateACB handles all three rules automatically using a two-pass algorithm. The Audit Provenance report shows exactly which rule was applied to each disposal.
Annual Exempt Amount (AEA)
The first portion of your net capital gains each tax year is exempt from CGT:
| Tax Year | AEA |
|---|---|
| 2024/25 onwards | £3,000 |
| 2023/24 | £6,000 |
| 2022/23 and earlier | £12,300 |
The AEA is a deduction, not an exemption — gains above the AEA are taxed, not the full amount. PrivateACB shows the AEA deduction in both the dashboard TaxSummaryCard and the SA108 report.
What the UK Doesn’t Have
The UK’s crypto tax rules differ from Canada, the US, and Australia in several important ways:
- No wash sale rule — The 30-day rule changes cost allocation, but does not deny losses
- No superficial loss rule — No backward-looking loss denial window
- No lot tracking — UK uses pooling (Section 104), not individual lots
- No per-account tracking — No requirement to track cost basis per wallet or exchange
- No short-term/long-term distinction — All gains taxed at the same CGT rate regardless of holding period
- No CGT discount — Unlike Australia’s 50% discount, UK has no holding period discount
GBP Currency and Market Data
Crypto prices in GBP are sourced from CoinGecko, which natively supports GBP pricing (vs_currency=gbp). No foreign exchange conversion is needed for GBP-priced assets. For transactions on exchanges that report prices in USD, PrivateACB handles the conversion to GBP automatically.
Regulatory References
- TCGA 1992, Section 104 — Section 104 holding (pooled shares/tokens)
- TCGA 1992, Section 105 — Same-day identification rule
- TCGA 1992, Section 106A — 30-day bed & breakfasting rule
- HMRC Cryptoassets Manual, CRYPTO22200-22257 — Application of share identification rules to cryptoassets
- HMRC Capital Gains Manual, CG51560 — Section 104 pool mechanics
- Finance Act 2024 — CGT rate changes effective 30 October 2024 (18%/24%)