Wales has finalised how business rates increases from the 1 April 2026 revaluation will be phased. Where bills rise by more than £300, two-thirds of that increase is removed in 2026–27, a third in 2027–28, with full liability from 1 April 2028. The Non‑Domestic Rating (Chargeable Amounts) (Wales) Regulations 2025 come into force on 31 December 2025 and apply from 1 April 2026. Source: Welsh Government guidance and Written Statement.

Eligibility is narrow and operational. The property must appear on the local or central list on 31 March 2026 and on each day up to the bill date; the same ratepayer must have occupied it on 31 March 2026; and the increase must exceed £300. Properties subject to a Section 44A partial‑occupation apportionment are excluded. Central‑list ratepayers are in scope.

What this means in cash terms is straightforward: in year one you pay your pre‑revaluation bill plus 33% of the increase; in year two you pay the base plus 66%; from 2028–29 you pay the full post‑revaluation amount. The taper is calculated daily and baked into the charge-no separate application needed for most firms.

Two definitions sit behind the maths. “Base liability” is the annualised charge for 31 March 2026 after statutory reliefs. The “notional chargeable amount” is what your bill would be on 1 April 2026 if the taper did not exist. The reduction each year is a percentage of the difference between those two figures.

Here’s a worked example. A factory has a base liability of £30,000 and a notional 2026–27 bill of £45,000. The £15,000 increase is smoothed so the 2026–27 bill becomes £34,950; in 2027–28 it becomes £39,900; from 2028–29 it is £45,000. Finance teams should model this on a monthly accrual basis to avoid year‑end surprises.

Administration should be automatic. Local authorities will adjust local‑list bills to apply the taper; for central‑list entries the Welsh Government will do it. Even so, ratepayers should check demand notices, confirm that eligibility tests have been met, and query anomalies quickly with billing teams.

This taper sits alongside structural changes to multipliers from April 2026. The standard multiplier will fall to 0.502; a new retail multiplier at 0.350 will support small and mid‑sized shops; and a higher multiplier of 0.515 will apply to the largest properties. Ministers estimate £116 million of support over two years through the taper.

Planning prompts for CFOs and owners: if a different occupier becomes the ratepayer after 31 March 2026, the tapered protection ceases. Partial‑occupation relief under Section 44A can be valuable in other contexts but it disqualifies you from the transitional scheme. Map lease events, refits and M&A timelines against these rules before Q2 FY26.

Remember the wider relief picture. Wales’ permanent business‑rates reliefs are worth about £250 million a year, and roughly two‑thirds of properties pay no bill or receive some relief. The taper is layered on top of any other reliefs you qualify for-model interactions carefully to avoid double counting.

Key dates and data points: rateable values are based on an antecedent valuation date of 1 April 2024. The Valuation Office Agency is due to have draft lists available by the end of 2025 ahead of bills landing from April 2026. Treat 1 April 2028 as the step‑off when transitional protection ends.