Datahold will build and manage a database of more than two million records. It will also manage all aspects of the Clash Media database including maintaining and improving data quality, list cleaning and suppression, and analytics and modelling.
The data has been collected by Clash Media from a variety of sources including its affiliate network and its offices in the UK, US, Scandinavia and Germany.
The database will include data such as email addresses, telephone numbers, postal details, marital status, gender and recency. All data will be categorised by industry sectors.
Dave Watson, new business director at Datahold, said: "Clash Media are one of the UK's best known performance-based marketing companies producing millions of qualified leads each month.
"We're pleased to have been chosen to build and manage their new UK database and also to be given responsibility for making recommendations based on our analytical expertise."
Luke Pursey, managing director of Clash Media, said: "Datahold are the leading player in B2C database build and management, not least because their offshore model provides the best service-level agreements available.
"This new database is a hugely important launch for us and we feel confident it will become one of the leading suppliers of B2C data for DM campaigns."
Datahold is headquartered in London and has offices in the Philippines. It employs more than 70 staff worldwide and claims to manage more UK list data sets than any other bureau in the UK.