Taxes · Explainer
Capital gains tax: what triggers it and what does not
Tax is generally due on disposal, not on paper growth. Which disposals count, and what you can offset, decides the bill.
The short answer
- Unrealised gains are usually untaxed; the taxable event is the disposal.
- Switching funds, gifting and some transfers can all count as disposals.
- Losses and allowances must usually be claimed within a time limit.
Capital gains tax applies to the profit realised when an asset is disposed of, calculated as proceeds minus the acquisition cost and allowable expenses. Holding an asset that has risen in value generally creates no liability until something happens to it.
Disposals people miss
- Switching between funds, even within the same platform or fund family.
- Gifting an asset to someone other than a spouse or civil partner, in many systems.
- Exchanging one crypto-asset for another, which is treated as a disposal in several jurisdictions.
- Transferring assets out of a tax-sheltered account.
Losses are an asset
Realised losses can normally be set against realised gains, and in some systems carried forward indefinitely — but only if reported in the correct year. Failing to declare a loss can quietly forfeit relief that would have been worth real money later.
Shelters do the heavy lifting
Tax-advantaged accounts remove the reporting problem entirely for assets held inside them. Using the available allowance each year is usually more effective than any disposal strategy applied to a taxable account.
Sources
- Topic no. 409, Capital gains and losses — Internal Revenue Service
- Capital Gains Tax — GOV.UK / HMRC
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How this article was produced
- Responsible desk:
- Taxes
- Published:
- 11 Aug 2026, 07:35 UTC
- Last updated:
- 11 Aug 2026, 07:35 UTC
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This article is general financial information and journalism, not personalised financial, investment, tax or legal advice.