Nationwide Housing Prices MoM

Nationwide Housing Prices MoM is the month-on-month reading of the Nationwide House Price Index (NHPI), where MoM means change versus the prior month. Nationwide Building Society, a large UK mortgage lender, compiles it from its own house purchase approvals at the post-survey stage, after property survey.

It covers UK purchases financed by Nationwide mortgages and tracks a mix-adjusted typical home, which holds property quality constant rather than averaging sales. The series spans decades of monthly history, and it is not the official ONS (Office for National Statistics) House Price Index. Arabic financial outlets also call it the average home price in Britain.

Each release covers mortgage approvals from one calendar reference month at the post-survey approvals stage. It appears around the turn of the month after the reference month, usually in the first working days, near 07:00 London time.

Each release publishes a headline table with seasonally adjusted index, monthly change, annual change against the prior year, raw average price and commentary. Quarter-end releases add regional tables, special research accompanies each report, figures are recalculated monthly so history can revise, and a positive MoM means prices rose. Revised values carry a flag, and historic data plus chart archives stay available.

The index has no weighted components, so it moves with price shifts in the qualities held constant for the typical home.

• UK location: the part of the country or region where the property sits.
• Neighbourhood type: the demographic kind of area, using 59 categories including retirement and council areas.
• Property design: the dwelling form, such as detached, semi-detached, terraced, bungalow or flat.

In one past release the index was flat on the month at 0.0% yet down 5.3% on the year, since annual rates carry older falls. The seasonally adjusted index stood at 511.7 against 511.9 for the prior month, while the average price was 257808 pounds against 259153 pounds. That annual fall was worth about 14500 pounds.

Flats fell 5.7% on the year, against falls of 3.6% for detached, 4.6% for semi-detached and 5.3% for terraced, as flat sales held up better. All regions fell on the year, South West down 6.3% and Northern Ireland down 1.8%, while buyers moved to smaller homes. Payments took 38% of take-home pay against a 29% long-run average.

1. Approvals sample: Take all Nationwide house purchase lending at the post-survey approvals stage in the reference month, after property survey but before completion.
2. Mix adjustment: Estimate the price of a fixed typical home with set location, neighbourhood type and design, so shifting sales mix cannot move the index.
3. Atypical filter: Remove atypical properties that would distort results, where atypical means unusual cases unfit for the typical price; no other expert judgement applies.
4. Index build: Build the index and the not seasonally adjusted average price, where not adjusted means raw price before seasonal correction.
5. Seasonal adjustment: Seasonally adjust indices with the US Census X12 seasonal filter, then compute MoM% as 100 times the gain divided by the prior index. For example, 511.7 against 511.9 gives about 0.0%.
6. Recalculation: Recalculate the full series each month with new data and fresh seasonal factors, which can revise past values.