They know your mobile phone number, when your car insurance expires and where you live, although you have probably never heard of them.

Data Locator Group (DLG), the UK database provider that was acquired last year in a management buyout backed by Promethean, has now been bought by the private equity arm of Kaupthing, the Icelandic bank, for £75 million in a deal expected to be announced today.

Promethean, headed by Sir Peter Burt, the former ITV chairman, is understood to have paid about £25 million for its 71 per cent stake in March 2006.

Since that deal last year DLG has made two acquisitions for undisclosed sums including the UK operations of Wegener Direct Marketing. The second acquisition was of 43 plc, an online marketing business also based in the UK.

DLG’s value has soared amid growing demand for online data gathering and delivery. Direct marketing by mailshots, telephone and the internet is a growing industry.

It was originally thought that the company would be floated once the acquisitions had been integrated within the business.

DLG’s clients include Oxfam, Telegraph Media Group, Ogilvy and TNS Global.

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