Block and portfolio sales

How these are found

A transfer is flagged when several distinct addresses share one date and one price of £1m or more, within at most two districts. The obvious rule — "lots of addresses share a price" — is useless: on 2025 alone it flags 344 unrelated houses that each sold for a round £350,000 on 28 March, a quarter-end completion date, spread across 186 districts. A real portfolio has the opposite shape: a few titles, one large price, one place.

Sharing a building is decisive on its own — a flat sold with its parking space is one purchase filed as two titles, and left in the data it publishes an eight-figure car parking space. Sharing only a district is not: two unrelated prime houses can fetch the same round sum on the same day in the same borough, and those stay marked as possible rather than confirmed.

Category B, HM Land Registry’s "additional price paid" class, is used only as corroboration. It covers 16.5% of all rows — repossessions, buy-to-lets, right-to-buy and sales under a power of sale as well as bulk transfers — so it is far too broad to trigger on by itself.