House Price Index MoM

The UK House Price Index MoM is the official monthly change in UK home prices on a seasonally adjusted basis. It is a joint production by HM Land Registry, ONS, Registers of Scotland and LPSNI, with calculation by ONS as an accredited official statistic.

It covers all full market value residential sales, cash and mortgage, measured at completed sale. It measures nominal mix-adjusted change for a fixed home mix. Shifts in sales mix do not distort it. It is not adjusted for inflation.

Coverage draws on a near census of registrations from Price Paid data, Registers of Scotland and tax data for Northern Ireland. Records are matched to valuation lists, energy certificates, Acorn geo-demographic data and mortgage records for buyer splits.

It does not measure asking prices, mortgage approval prices, valuations or remortgages. It excludes commercial property, non market transfers such as gifts or discounted transfers, and real inflation adjusted change. Halifax and Nationwide track own mortgage approvals only with no cash sales. Rightmove tracks asking prices in a timelier but narrower series.

The reference period is the completion month. Sales enter only after registration from 2 weeks to 2 months after completion and longer for new builds.

The opening estimate uses about 40% of transactions, then about 80% and 85% as more registrations arrive. Release follows a fixed morning schedule at 9:30 UK time.

Northern Ireland updates on a quarterly cycle with its price held constant for 2 interim months. Each release adds average prices, indices, growth rates, volumes, bulletin analysis and revision tables. It withholds incomplete volume data for incomplete months.

Each release revises the prior 12 months and 4 quarters for Northern Ireland as more registrations arrive. Markets read direction of change and avoid overweighting any single estimate. Early months stay provisional and call for careful reading.

Monthly change reflects shifts in priced home features and market funding, not asking prices.

• Location: district in Great Britain and market area in Northern Ireland set the area price level.
• Acorn group: neighbourhood affluence and demographics from geo-demographic classification shape local values.
• Property type: detached, semi-detached, terraced, flat or maisonette premium reflects structure and land use.
• Floor space: size in square metres priced at a per-square-metre rate rewards larger homes.
• Number of rooms: capacity adds value beyond floor size for bedrooms and living space.
• New-build status, 9%: new-build premium over existing homes carries weight of about 9%. The split is withheld for the 2 provisional estimates as unreliable, while the model explains about 80% of price variation.

Adjusted and non-adjusted monthly readings differ by design. Seasonal patterns are removed in the adjusted series only.

• Assemble transactions: completed market-value sales from Price Paid, Registers of Scotland and tax data, matched to valuation, energy, Acorn and mortgage records.
• Fix the basket: set a fixed basket reflecting the prior complete transaction mix on a regular annual cycle, so comparisons stay like for like.
• Hedonic regression: estimate log price from features, where coefficients serve as model weights. The model gives each basket home a predicted price, with a reduced model without the new or existing flag for the opening estimate.
• Geometric mean: average predicted prices with the geometric mean, by multiplying values and taking the root, which limits distortion from high-value homes.
• Index ratio: divide the current mean by the prior mean and multiply the prior index, anchored to a fixed reference average price.
• Seasonal adjustment and monthly change: compute adjusted series for regions and nations only. Report monthly change on that basis and hold Northern Ireland constant for 2 interim months. Express change as the move in adjusted price divided by the prior adjusted price in percent.