John Billett, the 61-year-old founder and chairman of Billetts, will pocket nearly £10m for his 75% stake in the company, if it meets the profits targets set by its new owner.
The other key shareholders, including Andy Pearch, the chief executive of Billetts' media auditing division, and David Bridges, the chief executive of its marketing services division, will share the remainder. The company will retain its Billetts branding.
Payments will be made in two parts: an initial £7.5m payment, mainly in cash, followed by a further £5.6m in earn-out consideration, subject to Billetts meeting profit targets over the next two financial years.
Billett and the rest of the Billetts management team will remain in place and the working directors, including Ron de Pear and Rob Hill, will become shareholders in Thomson Intermedia.
The deal was completed on Tuesday evening after months of negotiation. Billett said: "We took the view 18 months ago we wanted to accelerate the business, add new services and expand geographically. A realisation strategy began to emerge and we hired KPMG Corporate Finance, which devised a business strategy."
He added that the acquisition would allow Billetts to widen its offer and enable it to expand. Billetts America, which launched as a majority-owned joint venture with the US auditor Erwin Ephron, also comes under the control of Thomson Intermedia.
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