The UK’s longest-running monthly house price survey, the Halifax House Price Index, has been sold.

Financial data company Markit is buying the monthly survey from Lloyds Banking Group for an undisclosed sum. The deal is due to complete later this year.

Both the name of the index, which goes back to January 1983, and its methodology will remain unchanged after the transaction completes.

A Halifax spokesperson said that the house price survey had originally been launched as a tool for the media, but over the years had developed into a major financial benchmark that was widely used by external organisations.

She said: “The original purpose of it and what it is today are two very different things.

“It is not really a core part of our business, and it makes sense for someone like Markit to administer it.”

Markit calculates more than 14,000 indices around the world and in the UK is probably best known for the “sentiment” survey conducted in partnership with Knight Frank.

The Halifax House Price Index is based on a monthly sample of the bank’s mortgage approvals and typically covers some 15,000 home transactions – some of which may not proceed to completion. The data is “seasonally adjusted”.