If you sell nothing, you pay no CGT.
You only pay CGT if:
- You’ve realised (sold) some investments, and
- Your total gains in that tax year exceed your CGT allowance.
100,000 invested grows 10% into 110,000
When you sell a portion of your investment, you’re taking out some of the original money you invested and some of your profit, at the same time.
When the investment has grown to 110,000:
- 9.09% of that is profit
- 90.91% of that is your original capital
How to calculate it:
Growth / divided by / Total, Present Value of Investment
10,000 / 110,000 = 0.0909(090909etc)
If you sell 50,000 - you’re essentially selling 45.45% of the entire, total, present investment value - again some profit, some original investment.
How to calculate it:
50,000 / 110,000 = 0.4545(4545etc) = 45.45%
How to calculate how much of the original investment you’ll be taking out:
100,000 * 0.4545 = 45,455 (rounded up)
How to calulate how much profit you’ll be taking out:
10,000 * 0.4545 = 4,545
To check your maths is correct, add the two, and they should add up the amount you wanted to close in the first place: 50,000 (45,455 + 4,545).
The important thing is that with each sale, you/T212/HMRC look at it as capturing some profit as well as taking out some of your original investment.
You only pay CGT on the realised gains above the annual allowance; your original investment is never taxed (e.g. you’ll pay tax on the 4,545 only not the 45,455, since only the former is profit, the latter is your investment).
If you withdraw funds from an investment that’s in the red, there’s no profit, hence no tax. You’re just taking out your funds.