UK CGT Bed-and-Breakfast 30-Day Rule Complete Guide 2026/27

Q: What is the Bed-and-Breakfast 30-day rule?

Bed-and-Breakfasting : historical UK tax-loss harvesting practice - sell shares to crystallise gain / loss for Capital Gains Tax (CGT), immediately repurchase next day. Section 106A TCGA 1992 (inserted by FA 1998) introduces the "within 30 days" matching rule to prevent it. If you sell shares + repurchase SAME shares within 30 days, disposal matched against repurchase (not Section 104 pool). Effect : no real disposal recognised for CGT. Gain / loss preserved. Genuine BUT : tax-loss harvesting blocked.

Q: How do the Section 104 pool, same-day and 30-day rules rank?

3-tier matching hierarchy under Section 105 TCGA 1992 (same-day) + Section 106A TCGA 1992 (30-day) + Section 104 TCGA 1992 (pool): (1) Same-day matching first : shares sold today matched against shares acquired today. (2) 30-day matching next : shares sold today matched against shares acquired in next 30 days. (3) Section 104 pool : remainder matched against pooled holding (weighted average cost). Pool concept : all holdings of same share treated as single asset with average cost. Each new purchase added to pool, each sale withdrawn at average cost. Worked example : Sept hold 1,000 BP shares at £4 average pool cost. Sell 500 at £5 on Oct 1. Buy 200 at £5.20 on Oct 15. Matching : (1) Same-day Oct 1 : 0 purchases. (2) 30-day window : 200 of the 500 sold matched against Oct 15 purchase. Gain = (£5 × 200) - (£5.20 × 200) = -£40 LOSS. (3) Pool : 300 of 500 from pool. Gain = (£5 × 300) - (£4 × 300) = £300. Total reportable gain : £260.

Q: Is the bed-and-spouse strategy allowed?

Bed-and-Spouse : sell shares, spouse immediately repurchases. Different person + 30-day rule doesn't apply across taxpayers . Gain crystallised by seller. Spouse acquires at market price. Useful for : (1) Tax-loss harvesting : crystallise losses to offset gains. (2) Annual Exempt Amount (AEA) utilisation : maximise each spouse's £3,000 AEA. (3) Band utilisation : shift gain to lower-band spouse. (4) Business Asset Disposal Relief (BADR) cap optimisation : shift £1m cap usage. Worked example : holder has £20k gain. Sells half (£10k gain). Spouse buys back same day. Wife (basic-rate) reports £10k gain - £3k AEA = £7k × 18% = £1,260. Holder kept other half. Saves vs single seller higher-rate.

Q: Is the bed-and-ISA strategy allowed?

Bed-and-ISA : sell shares from GIA + immediately repurchase in Individual Savings Account (ISA). 30-day rule applies (same person) : BUT ISA shielded from future CGT entirely. Effect : (1) Sale + repurchase within 30 days = matched : no immediate gain crystallisation. (2) After 30 days, original gain crystallises against Section 104 pool . (3) ISA holdings tax-free : all future gains tax-free. Strategic timing : (1) Use B&I to migrate holdings to tax-free wrapper . (2) Within £20,000 / year ISA limit . (3) Capital gains within AEA absorbed : above AEA, CGT due. Worked - 500 BP shares at £4 cost, £5 current. AEA available : Sell GIA + buy ISA same day . Section 104 match next-day re-buy . £500 gain absorbed by AEA . Net £0 tax + assets now in ISA permanently tax-free .

Q: What should investors check under the CGT matching rules?

Investor checklist : (1) Track Section 104 pool : all purchases + disposals same security. (2) Avoid accidental 30-day rebuy : blocks tax-loss harvesting. (3) Use Bed-and-Spouse : legal alternative to B&B. (4) Use Bed-and-ISA : shift to tax-free wrapper. (5) AEA timing : split disposals across tax years for £3k × 2 + AEAs. (6) Spouse share transfer pre-sale : utilise both AEAs + bands. (7) BADR / IR claim where eligible : 18% / 14% rates. (8) Capital losses claim : carry forward indefinitely. (9) Crypto pool tracking software : Koinly / Recap / CoinTracker. (10) SA filing for capital gains : over £3k or £50k+ disposal proceeds.

UK CGT Section 104 share pool + 30-day matching rules 2026/27 - same-day rule (Section 105 TCGA 1992), 30-day rule (Section 106A TCGA 1992), bed-and-breakfasting prevention. Worked examples for share + crypto disposals + reacquisitions.

2026/27 tax year

Capital Gains
Investor
UK-wide

Sections 105 (same-day) + 106A (30-day) + 104 (share pool) of TCGA 1992 govern UK CGT matching on share + crypto disposals. This guide covers same-day, 30-day, and pool matching hierarchy, anti-bed-and-breakfast mechanics, bed-and-spouse and bed-and-ISA strategies, and crypto application.

Matching hierarchy

Priority	Rule	Effect
1st	Same-day	Sale matched against same-day buy
2nd	30-day rule	Sale matched against next 30 days' buys
3rd	Section 104 pool	Sale matched against pool (average cost)

Frequently asked questions

What is the Bed-and-Breakfast 30-day rule?

Bed-and-Breakfasting: historical UK tax-loss harvesting practice - sell shares to crystallise gain / loss for Capital Gains Tax (CGT), immediately repurchase next day. Section 106A TCGA 1992 (inserted by FA 1998) introduces the "within 30 days" matching rule to prevent it. If you sell shares + repurchase SAME shares within 30 days, disposal matched against repurchase (not Section 104 pool). Effect: no real disposal recognised for CGT. Gain / loss preserved. Genuine BUT: tax-loss harvesting blocked.

How do the Section 104 pool, same-day and 30-day rules rank?

3-tier matching hierarchy under Section 105 TCGA 1992 (same-day) + Section 106A TCGA 1992 (30-day) + Section 104 TCGA 1992 (pool): (1) Same-day matching first: shares sold today matched against shares acquired today. (2) 30-day matching next: shares sold today matched against shares acquired in next 30 days. (3) Section 104 pool: remainder matched against pooled holding (weighted average cost). Pool concept: all holdings of same share treated as single asset with average cost. Each new purchase added to pool, each sale withdrawn at average cost. Worked example: Sept hold 1,000 BP shares at £4 average pool cost. Sell 500 at £5 on Oct 1. Buy 200 at £5.20 on Oct 15. Matching: (1) Same-day Oct 1: 0 purchases. (2) 30-day window: 200 of the 500 sold matched against Oct 15 purchase. Gain = (£5 × 200) - (£5.20 × 200) = -£40 LOSS. (3) Pool: 300 of 500 from pool. Gain = (£5 × 300) - (£4 × 300) = £300. Total reportable gain: £260.

Is the bed-and-spouse strategy allowed?

Bed-and-Spouse: sell shares, spouse immediately repurchases. Different person + 30-day rule doesn't apply across taxpayers. Gain crystallised by seller. Spouse acquires at market price. Useful for: (1) Tax-loss harvesting: crystallise losses to offset gains. (2) Annual Exempt Amount (AEA) utilisation: maximise each spouse's £3,000 AEA. (3) Band utilisation: shift gain to lower-band spouse. (4) Business Asset Disposal Relief (BADR) cap optimisation: shift £1m cap usage. Worked example: holder has £20k gain. Sells half (£10k gain). Spouse buys back same day. Wife (basic-rate) reports £10k gain - £3k AEA = £7k × 18% = £1,260. Holder kept other half. Saves vs single seller higher-rate.

Is the bed-and-ISA strategy allowed?

Bed-and-ISA: sell shares from GIA + immediately repurchase in Individual Savings Account (ISA). 30-day rule applies (same person): BUT ISA shielded from future CGT entirely. Effect: (1) Sale + repurchase within 30 days = matched: no immediate gain crystallisation. (2) After 30 days, original gain crystallises against Section 104 pool. (3) ISA holdings tax-free: all future gains tax-free. Strategic timing: (1) Use B&I to migrate holdings to tax-free wrapper. (2) Within £20,000 / year ISA limit. (3) Capital gains within AEA absorbed: above AEA, CGT due. Worked - 500 BP shares at £4 cost, £5 current. AEA available: Sell GIA + buy ISA same day. Section 104 match next-day re-buy. £500 gain absorbed by AEA. Net £0 tax + assets now in ISA permanently tax-free.

Does the 30-day rule apply to crypto?

Sections 104, 105 + 106A TCGA 1992 apply to CRYPTOCURRENCY too: HMRC's view in cryptoassets manual. Same matching hierarchy: same-day, then 30-day, then Section 104 pool. Per-coin pool: BTC, ETH, etc. each separate pool. Implications: (1) Crypto traders cannot bed-and-breakfast: 30-day repurchase matched. (2) Stablecoin shuffling within 30 days: matching applies. (3) Wash trades across exchanges: same crypto, same person, 30-day window = matched. Strategic considerations: (1) Hold 31+ days between sell + repurchase: clean disposal + new acquisition. (2) Crypto-to-crypto trades: each swap = disposal at market value. (3) DeFi yield + reinvestment: complex matching. (4) Pool calculation per coin: track all purchases + disposals separately. (5) Specialist crypto-tax tools (Koinly, Recap): handle Section 104 + 30-day automatically.

What should investors check under the CGT matching rules?

Investor checklist: (1) Track Section 104 pool: all purchases + disposals same security. (2) Avoid accidental 30-day rebuy: blocks tax-loss harvesting. (3) Use Bed-and-Spouse: legal alternative to B&B. (4) Use Bed-and-ISA: shift to tax-free wrapper. (5) AEA timing: split disposals across tax years for £3k × 2 + AEAs. (6) Spouse share transfer pre-sale: utilise both AEAs + bands. (7) BADR / IR claim where eligible: 18% / 14% rates. (8) Capital losses claim: carry forward indefinitely. (9) Crypto pool tracking software: Koinly / Recap / CoinTracker. (10) SA filing for capital gains: over £3k or £50k+ disposal proceeds.