Mansion Tax: UK Property Prices Already Shifting Around the £2 Million Mark

A new annual charge on higher value properties is already reshaping seller and buyer behaviour in the UK property market, despite being more than two years away from taking effect. Since its announcement in the Autumn 2025 Budget, properties around the £2 million mark have shown a measurable shift in both listing prices and transaction patterns.

This article sets out what the charge involves, the market data already reflecting its impact, and how the Office for Budget Responsibility (OBR) has factored the effect into its revenue projections ahead of the April 2028 implementation date.

What Is the Mansion Tax?

The High Value Council Tax surcharge will apply to residential properties valued at £2 million or more annually, based on 2026 property prices assessed by the Valuation Office Agency (VOA). Revaluations are scheduled every five years thereafter.

Unlike stamp duty, which is a one-off transaction cost, this is a recurring annual liability, payable each year the property is held above the threshold.

What Is Happening to Prices Around the £2 Million Mark?

The pricing shift around the £2 million threshold is already visible in market data. In the two months following the Budget, listing and transaction patterns around the threshold shifted in a consistent direction.

The number of properties listed between £2 million and £2.2 million fell by 6.5% year on year. Over the same period, listings priced between £1.8 million and £2 million rose by 5.6%. A greater share of properties in the £1.8 million to £2.2 million range also received offers below the £2 million mark.

The pattern reflects a well-documented market response to tax thresholds. When a recurring annual charge applies above a fixed point, sellers and buyers adjust prices and offers to remain below it. This behaviour was seen previously at stamp duty thresholds and is now emerging around the £2 million mansion tax band. Economists refer to this clustering of prices just below a tax threshold as price bunching. The OBR anticipated this response when modelling the charge, projecting that the effect will become more pronounced as the April 2028 implementation date approaches.

The underlying financial calculation is straightforward:

• A property sold at £1,999,999 falls outside the scope of the charge entirely
• A property sold at £2 million or above attracts the surcharge annually until the next revaluation
• The difference of a single pound carries a recurring annual cost of at least £2,500

The Knock-On Effect on Other Tax Revenues

The bunching effect carries wider fiscal consequences. As transactions complete at prices just below £2 million rather than above it, the values on which stamp duty land tax and capital gains tax are calculated fall correspondingly.

The OBR's own modelling projects a £200 million reduction in combined Stamp Duty Land Tax and Capital Gains Tax receipts as a direct result of anticipated price bunching around the threshold.

How Properties Will Be Valued

The 2026 VOA assessment carries lasting consequences for properties sitting close to the £2 million mark. A property assessed at £1.95 million falls outside the charge. A property assessed at £2.05 million attracts the annual surcharge until the next revaluation cycle. This applies regardless of what the property subsequently sells for in the intervening period.

Conclusion

The mansion tax is a measure scheduled for April 2028. The market response it has already triggered suggests the full impact on property pricing, transaction values, and tax revenues will become increasingly visible as that date approaches.

The OBR's decision to factor the anticipated effect into its own revenue projections confirms that the pricing shift around the £2 million threshold is not incidental. It is a structural market adjustment to a scheduled fiscal change.