Bed and ISA — How to Reduce Capital Gains Tax on Your Shares Legally

The original “bed and breakfasting” — selling shares on Friday and rebuying on Monday to crystallise a loss — has been dead since 1998. But there are perfectly legal variations that can genuinely reduce your CGT bill. The most popular is “bed and ISA”.

What is Bed and ISA?

The idea is simple: sell shares in your taxable General Investment Account (GIA), then immediately repurchase the same shares inside your Stocks and Shares ISA. The sale triggers a disposal for CGT purposes, but any future growth happens within the ISA — completely tax-free.

The mechanics:

1. Sell shares in your GIA. This is a disposal — calculate the gain or loss using normal HMRC matching rules.

2. Transfer the cash to your ISA (or use existing ISA allowance).

3. Repurchase the same shares inside the ISA.

The 30-day bed and breakfast rule does not apply here. That rule only catches repurchases in the same capacity — buying back in your GIA within 30 days. An ISA is a different wrapper, so the matching rules treat the ISA purchase as a completely separate holding.

Some platforms (Trading 212, for example) offer a one-click “move to ISA” feature that automates this. Others require you to do the sell and rebuy manually.

When it makes sense

Bed and ISA works best when:

Your shares have a relatively small gain — ideally within or close to your £3,000 annual exemption. You crystallise a small taxable event now to protect all future growth.

Your shares are sitting at a loss. You crystallise the loss (which you can carry forward to offset future gains), then repurchase inside the ISA where future growth is sheltered.

You have unused ISA allowance. The annual limit is £20,000 for 2025/26.

It’s less attractive if your shares have a very large unrealised gain, because crystallising it all at once could push you into the higher CGT rate.

Worked example

Emma holds 500 shares of VWRL in her GIA. She bought them at £80 each (total cost £40,000). They’re now worth £92 each (total value £46,000).

She sells all 500 in her GIA: gain = £46,000 − £40,000 = £6,000.

After the £3,000 annual exemption: taxable gain = £3,000.

At 18% (basic rate): CGT due = £540.

She immediately buys 500 VWRL shares inside her ISA at £92 each.

Result: Emma paid £540 in CGT now, but all future growth on those shares is completely tax-free. If VWRL grows to £120 per share, she’ll have a paper gain of £14,000 — zero tax. Without the bed and ISA, that £14,000 gain would eventually cost her £1,980 in CGT (at 18%) or £2,640 (at 24%).

Bed and Spouse

Similar principle, different wrapper. You transfer shares to your spouse (which happens at “no gain, no loss” under HMRC rules), and your spouse sells them. This works when:

Your spouse has unused annual exemption (£3,000).

Your spouse is in a lower tax band than you.

Your spouse has capital losses to offset.

The key requirement: the transfer must be genuine. Your spouse must actually own the shares — you can’t just run the proceeds through their name. HMRC can (and does) challenge artificial arrangements.

Risks and things to watch

Market risk: Between selling and rebuying, the share price might move. If it shoots up, you buy back at a higher price. Some platforms offer near-instant bed and ISA to minimise this window.

ISA allowance limit: You can only put £20,000 per year into ISAs. If the shares are worth more than your remaining allowance, you’ll need to split the bed and ISA across multiple tax years.

Transaction costs: Selling and rebuying costs fees. Factor this into your calculation — a £10 saving in future CGT isn’t worth £25 in trading fees.

The 30-day rule within GIA: If you sell in your GIA and accidentally rebuy in the GIA (not the ISA) within 30 days, the 30-day rule applies and changes your cost basis. Make sure you’re rebuying in the right account.

Use TaxBull’s sell simulator to model the CGT impact of a bed and ISA before you execute it. Enter the number of shares, the sale price, and see exactly what the tax bill would be — including whether it pushes you into the higher rate.

This is general information about tax planning strategies, not personal advice. The suitability of these strategies depends on your individual circumstances. Consult a financial adviser or tax professional before acting.