Considering how few people ever have to pay it, there’s always a lot of worry and political noise about capital gains tax on shares.

Capital gains tax (CGT) falls due on investments you sell for a profit in any given tax year, unless:

• The asset is sheltered in your ISAs or pensions.

• Your gains are covered by your annual capital gains tax allowance.

• Your gains can be sufficiently offset by your trading losses on other shares and assets. See our guide to defusing your capital gains below.

• The asset is exempt from capital gains tax.

CGT on shares and other assets is payable on your profits – that is, the difference between what you bought the asset for and what you sell it for, after costs.

For example if you buy a share for £100 and sell it for £1,100 ten years later, then your gain equals £1,000.

CGT is payable on your total taxable gains in a tax year. All capital gains and losses are pooled together for HMRC purposes.

If you fall into the ‘liable for tax’ net then you’ll pay CGT on the gains you’ve made above your tax-free allowance.

However, there are plenty of strategies you can legitimately use to reduce or eliminate capital gains tax on shares.

How much is capital gains tax on shares?

The capital gains tax rate on shares and other investments is:

• 18% for basic-rate taxpayers.
• 24% for higher-rate taxpayers and additional-rate taxpayers.

The rate you pay normally depends on your total taxable income.

Beware that basic-rate taxpayers can pay CGT at the higher rate, if your gains nudge you up a tax band.

You can work it out like this:

• Subtract your annual CGT allowance from your total taxable capital gains.

• Now add to that your total taxable income (including salary, dividends, savings interest, pensions income and so on, minus income tax allowances and reliefs).

• You pay the higher CGT rate on any profit that falls within the higher-rate income band.

Note: Scottish and Welsh taxpayers pay CGT at UK rates. A higher-rate Scottish taxpayer may pay capital gains tax at the UK basic taxpayer level.

You need to report your taxable gains via your annual self-assessment tax return.

Do this if your total taxable gain in the tax year exceeds your annual capital gains tax allowance…

OR

…if your sales of taxable assets are over £50,000 and you’re registered with HMRC for Self Assessment.

For example, if you sold £70,000 in shares, then you’d need to report the gain – because the amount sold is higher than the CGT reporting limit of £50,000.

Remember that sales of assets in ISAs and SIPPs aren’t reported. Don’t count them in your sums at all.

Offshore funds may pay tax at even higher than CGT rates

Capital gains on offshore funds are taxed at higher income tax rates – rather than CGT rates – if they:

• Do not have UK reporting fund status.
• Aren’t protected by an ISA or SIPP.

Check that any offshore funds you own (i.e. any not domiciled in the UK) have UK reporting fund status. This should be indicated on the fund’s website. HMRC also keeps a list of reporting funds.

A kicker is that you can’t cover non-reporting fund gains with your CGT allowance either.

Capital gains allowance on shares

The annual capital gains tax allowance (or Annual Exempt Amount) for your total profits is £3,000 – starting with the tax year 2024-2025. 

The UK Government regularly issues updates on CGT.

Capital gains tax exemptions

Some investments and other assets are exempt from capital gains tax:

• Your main home (in most cases)
• Individual UK Government bonds (not bond funds)
• Cash which forms part of your income for income tax purposes
• NS&I Fixed Interest and Index-Linked Savings Certificates
• Child Trust Funds
• Premium bonds
• Lottery or betting winnings
• Anything held in an ISA or SIPP

Capital gains tax is payable on shares, ETFs, funds, corporate bonds, Bitcoin (and other cryptocurrencies), and personal possessions worth over £6,000, including some collectibles and antiques.

Avoiding capital gains tax on shares

You can reduce your tax bill by offsetting trading losses against your capital gains. This is known as tax loss harvesting and it is a legitimate way to avoid capital gains tax on shares.

Terminology note Tax avoidance means legally reducing your tax bill such that HMRC won’t raise an eyebrow. Tax evasion involves things like owning shell companies like some people own shell suits, and funnelling cash to places with super-yacht congestion problems. These days the best phrase to use in polite society is tax mitigation.

Tax-loss harvesting involves selling shares and other assets for less than you originally paid for them. You strategically sell assets to realise losses you are already carrying in your portfolio, thus minimising your capital gains.

You don’t try to create losses with bad investments! That is where people can get confused.

The goal is ideally to reduce your gains to within your CGT allowance for the year.

We’ve come up with a quick step-by-step guide to help you do this.

1. Calculate your total capital gains so far

Tot up the gains, if any, you’ve made from selling shares, funds, and other chargeable assets this tax year (which starts on 6 April).

Your records (or your platform’s statements) are worth their weight at moments like this.

You need to include every sale you made over the tax year, regardless of what you did with the money afterward.

You make a capital gain on any share holding or fund (outside of ISAs or SIPPs) that you sold for more than you paid for it.

Work out each capital gain by subtracting the purchase value and any costs (such as trading fees) from the sale proceeds.

Add up all these capital gains to work out your total capital gain for the year.

Remember that shares and funds are not the only chargeable assets for CGT. You need to add all such capital gains into your total for the year. They all count towards your annual CGT allowance.

For example, any property – other than your main home – is potentially liable for CGT when you sell it.

See HMRC’s property guidance.

2. Calculate your losses

You register a capital loss if you sold shares, other investments, or a dodgy buy-to-let flat for less than you originally paid for it.

Add up all your losses over the year.

Grit your teeth, fling your hands over your eyes, and peek at your grand poo-bah loss.

Remember it’ll be okay because you’ll harvest the loss to neutralise your gains.

Sales of CGT-exempt assets don’t count towards capital losses. You can’t count disaster-trades that happened within your ISAs and SIPPs, for example.

Now for the good bit: offsetting your losses against your gains.

Let’s say you made £15,000 in capital gains on shares over the year, and you made capital losses of £14,000. Your total gain is £1,000.

Your losses have trimmed your gains to less than your annual CGT allowance. No capital gains taxes for you this year! Though possibly you should swap share trading for a more lucrative side hustle…

You can also offset unused capital losses you made in previous years, provided you notified HMRC of your loss via earlier years’ tax returns.

(Best do so in the future, eh?)

3. Consider selling more assets to use up more of your CGT allowance and so defuse future gains

You now know what your total capital gains for the year are (from step 1), after subtracting any capital losses (step 2).

If your total gains are higher than your CGT allowance

…then you’ll pay CGT on the gains above the allowance.

If you will have CGT to pay, then, before the tax year ends, consider selling another asset you’re carrying at a loss in order to offset that loss against your gains. This will further reduce or eliminate your capital gains tax bill.

If your total gains are less than your CGT allowance

…then you won’t have to pay any capital gains tax on those gains. Hurrah!

You don’t need to report the trades to HMRC, either, provided the total amount1 you sold the assets for is less than £50,000 or you’re not registered for Self Assessment taxes.

Before the tax year ends, consider selling down another asset you’re carrying that is showing a capital gain. This will enable you to use more of your available CGT allowance for the year – provided you don’t go over your annual allowance, of course.

Like this, you will defuse more of the capital gains you’re carrying. This can help you avoid breaching your CGT allowance in future years.

Admittedly this is pretty hard to do now, with the annual capital gains tax allowance having been cut to £3,000. (It used to be over £12,000.)

But every little helps.

If you’ve made an overall loss in a tax year

…after subtracting losses from gains, then you should declare it on your self assessment tax return.

Capital losses that you declare and carry forward like this can be used to reduce your capital gains in future years, when you might otherwise be liable for tax.

Losses can be a valuable asset, but only if you tell HMRC.

4. Reinvest any proceeds from sales

If you made any share sales to improve your capital gains position, then it’s time to reinvest the cash you raised.

These are the key techniques:

Bed and ISA / Bed and SIPP – Ideally you’ll now tax-shelter the money you released within a stocks and shares ISA or SIPP. That puts that money beyond the reach of capital gains tax in the future.

You can purchase exactly the same assets in your tax shelters, immediately.

New asset – If your tax shelters are full and you don’t want to earmark the money for next year’s ISA/SIPP, then you can reinvest in a different holding as soon as you’ve completed your sale.

This new investment starts with a clean slate for CGT purposes.

Beware the 30-day rule – You need to wait 30 days to reinvest in exactly the same share, ETF, or fund outside of your tax shelters.

If you flout the 30-day rule, then the holding is treated as if you never sold it. Which undoes all your tax-loss harvesting work.

Same but different – You can sidestep the 30-day rule by purchasing a similar fund (or share) that does the same job in your portfolio. For instance, the performance gap between the best global index funds is usually small.

You can defuse your gain, buy a lookey-likey fund straightaway with the proceeds, and keep your strategy on course.

Bed and spouse – This is the ever-romantic finance industry’s term for keeping an asset in the family. You sell the asset and encourage your spouse or civil partner to purchase it in their own account.

Your gain is defused and your significant other starts afresh with the same asset. This maximises the use of the two CGT allowances available to your household.

Tax on selling shares

The cost of trading is a bit like a tax on selling shares. It’s a can’t ignore factor that means selling for tax purposes isn’t always a good idea.

Trading costs include dealing fees, any stamp duty you pay on reinvesting the money, and also the bid-offer spread on the churn of your holdings.

Trading costs can reduce the benefit of defusing gains – especially on small sums.

It’s best to realise capital gains as part of your rebalancing strategy, when you’re already spending money to reduce your holdings in outperforming assets while adding to the laggards.

Deferring capital gains tax

You can defer capital gains tax on your shares and other assets by never selling.

No sale, no gain, no capital gains tax.

This is especially relevant if you’re an income investor who hopes to live off their dividends for the rest of their life.

In this case, you simply enjoy the dividend income from your shares and let the capital gain swell.

A risk though is you could someday be forced to sell.

Unforeseen emergencies are one problem. Routine events such as company takeovers, fund closures, or mergers can also count as disposals for CGT purposes. Then you’ll be hit with a big tax charge on the gains.

Best practice would therefore still be to try to defuse gains as you go, by using your annual CGT allowance as described above. This reduces the tax impact of any unforeseen sales in the future.

You can also defer paying CGT by rolling your gains into higher-risk investments known as Enterprise Investment Schemes. Do a lot of research before going down this path though. Such schemes are usually best left to sophisticated investors. 

Capital gains tax on inherited shares

Capital gains tax is not payable on the unrealised gains of shares belonging to someone who dies.

Inheritance tax may be due on the value of the shares, but not CGT.

Any gain you make between the date of the person’s death and your disposal (of the shares, not the body) does count for capital gains tax purposes though.

That’s assuming you couldn’t tuck your inherited assets into a tax shelter straightaway. (You may have had other things on your mind…)

Capital gains on shares help

HMRC issues lots of guidance on calculating capital gains tax on shares.

It’s also an unwritten rule that we writers must include a warning about ‘not letting the tax tail wag the investment portfolio dog’ in any article like this.

It’s true that there’s a fine line to tread between avoiding a bigger capital gains tax bill and becoming dangerously obsessed with minimising it.

But in practice, most of us can do a fair bit of selling to defuse CGT – without derailing our strategy – just by repurchasing the assets within an ISA or SIPP.

Think of it partly as an insurance policy. You may as well use the allowances you’ve got now, in case you get more money and more capital gains on shares in the future – but not more allowances.

The CGT allowance could even be reduced or removed by a future government. (Rueful hindsight: since the first version of this article – and that sentence – was written, the CGT allowance was halved!) 

Annual allowances like the capital gains tax allowance are usually a case of use it or lose it.

1. Note: the total amount not the capital gain! [↩]