Sui (SUI) Tax UK: Disposals, Staking and HMRC Rules
How HMRC taxes Sui in the UK — Capital Gains Tax on SUI disposals, Section 104 pooling, staking rewards as income, and the records you need for Self Assessment.
Sui launched in 2023 and quickly built a busy DeFi and memecoin ecosystem, which means many UK holders have far more SUI transactions than they realise. For HMRC, SUI is a cryptoasset like any other — property, not currency — so the standard Capital Gains Tax framework applies.
When SUI triggers Capital Gains Tax
You make a disposal when you sell SUI for pounds, swap it for another token (including stablecoins like USDC on Sui), or spend it. Each disposal is measured in GBP: proceeds at the time of the transaction minus your pooled cost. Swapping SUI into a memecoin on a Sui DEX such as Cetus or Turbos is a disposal of the SUI even though no fiat moved — the single most common thing active traders miss.
Section 104 pooling
HMRC requires share pooling. All your SUI sits in one Section 104 pool with a weighted-average cost per coin, and every sale draws a proportionate slice of that cost. Two matching rules take priority over the pool: the same-day rule and the 30-day "bed and breakfasting" rule, which stop you selling and quickly re-buying just to crystallise a loss.
Staking rewards are income
Sui is proof-of-stake, and delegating SUI to a validator earns regular rewards. HMRC treats those rewards as taxable income at their GBP value on the day you receive them — usually miscellaneous income for individuals. That value then becomes the cost basis of the new SUI, so when you eventually sell, CGT only applies to any further gain. Because Sui pays rewards every epoch (roughly daily), the number of small income entries adds up fast.
Object-based quirks don't change the tax
Sui's object model and sponsored transactions are technical details — they don't change the analysis. What matters to HMRC is what you acquired, what you disposed of, and the GBP values on the day. Gas fees paid in SUI when disposing of an asset are an allowable cost of that disposal.
Rates and records
For 2025/26 and 2026/27 the annual exempt amount is £3,000, with gains above taxed at 18% (basic rate) or 24% (higher rate). Keep dated GBP-valued records of every buy, swap, stake reward and sale. CryptoLens scans your Sui wallet directly, applies Section 104 pooling, separates staking income from gains, and produces an SA108-ready summary.
This is general information, not personal tax advice.
Frequently asked questions
Do I pay tax on Sui (SUI) in the UK?
Yes. HMRC treats SUI as property, so selling, swapping or spending it is a Capital Gains Tax disposal. Gains above the £3,000 annual allowance are taxed at 18% or 24% depending on your income band.
Are Sui staking rewards taxable in the UK?
Yes — rewards are income at their GBP value on the day received, and that value becomes the cost basis of the new SUI. A later sale is subject to CGT only on any additional gain.
Calculate your Sui CGT for HMRC
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