Same-day rule

Definition

Under HMRC rules, when you dispose of crypto, any acquisitions of the same token made on the same day are matched first, then acquisitions in the next 30 days, then the Section 104 pool. The same-day rule prevents same-day buy/sell churn from manipulating the pooled cost. South Africa does not apply a same-day matching rule; it uses base cost with FIFO.

Example

A UK investor buys and sells 2 ETH on the same day. HMRC matches that disposal to the same-day purchase first, before touching the pool.

Jurisdiction notes

• United Kingdom: HMRC matches disposals to same-day acquisitions first, then the 30-day window, then the Section 104 pool.
• South Africa: South Africa does not use same-day matching; FIFO and base cost apply.

See also

• Bed and breakfasting
• Section 104 pool
• FIFO (First-In, First-Out)
• Base cost