The OBR’s Economic and Fiscal Estimates publication shows that capital gains tax (CGT) is now estimated to raise an additional £6.1bn between 2025-26 and the end of the decade.

Half of the additional amount will come as a result of measures announced in the Budget.

Of the total increase, around £2.7bn is attributed to the reduced CGT relief on disposals to employee ownership trusts from 2026-27 onwards, while around a further £3.4bn is forecast to be hauled in by the Treasury due to rising equity prices.

The OBR’s estimate shows the increase in CGT collections over the remainder of the decade is sharp: £13.7bn was paid in CGT in 2024/25, with projections increasing this to £20.3bn in 2025/26 and £27.3bn by 2029-30.

Simon Martin, head of UK technical services at Utmost Wealth Solutions, a leading provider of insurance-based wealth solutions, said: “The OBR has significantly uprated its projected haul from Capital Gains Tax over the remainder of the decade with an additional £6.1bn forecast to be collected by 2029-2030.

“Under half of this increased tax take comes from the policy measure announced in the Budget in reducing reliefs on employee ownership trusts, demonstrating the impact of ongoing increases to equity and property valuations.

“The Chancellor, however, may not be counting her capital gains tax chickens just yet given the note from the OBR that the ‘Mansion Tax’ could drive a reduced yield in property taxes such as CGT. Behavioural changes may also be an increasingly important factor as those liable to rising CGT bills reconsider their options and long-term wealth strategies.”

HMRC collected £732m in Capital Gains Tax (CGT) in the first four months of 2025/26, a rise of 11% or £75m year on year (£657m).