Market Monitor operates a call centre from its headquarters in Buckinghamshire, which will be integrated into the Bonnier Group.
Hugh Bessant, the managing director of Prospect Swetenhams, will become managing director of Market Monitor in addition to his current role but the two businesses will continue to operate independently.
Janet Cockroft, the previous joint owner of Market Monitor, will remain with the company for two years in an advisory capacity, reporting to Bessant.
Bessant said: "Bonnier's data on directors and shareholders from the top UK companies will give brokers and clients an unrivalled source of intuitive contact data, as well as the ability to respond to specific customer needs in building niche databases.
"We already tele-verify 100,000 records every year and, using Market Monitor's call centre, will be able to verify more data. "
Market Monitor's database comprises 722,000 senior business people in the UK. No data is more than 12 months old and 70% has been checked in the past six months.
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