The £20 million deal sees a 27-strong management team investing varying amounts in the company in return for equity.
Matthew Freud, the founder of Freud Communications, is the only outside investor, taking a small stake.
The 27 WCRS investors are split into three tiers according to their level of investment: founding partners, managing partners and partners. All in each tier hold a broadly similar shareholding.
Havas will now hold a 24.9 per cent shareholding in the agency and WCRS will also remain the exclusive UK agency of the Havas division, Arnold Worldwide Partners.
The buyout sees Peter Scott rejoin WCRS 25 years after founding the agency with Robin Wight. The two will be the joint chairmen. Stephen Woodford will continue as the chief executive. Completing the senior team are Debbie Klein, the head of planning, Leon Jaume, the joint executive creative director, and Julian Hough, the business development director.
Woodford said: "This is an exciting and innovative deal for all parties. We've had fantastic support from our colleagues and I'm delighted that there will be 27 of us with a direct stake in the business. Our clients have been behind us all the way in this and our relationship with the other agencies within Arnold Worldwide Partners will continue."
LongAcre Partners, the corporate finance advisers, led the negotiations. The buyout follows a Havas network restructure last July.
This involved a simplified organisation and a strategy to make Euro RSCG Worldwide its single, global agency network.
INTERNAL EQUITY HOLDERS AT WCRS
- Founding partners
Julian Hough business development director; Leon Jaume joint executive creative director; Debbie Klein head of planning; Peter Scott co-chairman; Robin Wight co-chairman; Stephen Woodford chief executive
- Managing partners
Leslie Ali joint executive creative director; Sarah Bailes head of TV production; Niall Hadden human resources director; Emma Lawson head of account management; David Wood group account director
Will Barnett creative director; John Boyle creative services manager; Liz Darran board account director; Jo Dickson board account director; Gary Knight creative director; James Lethem senior TV producer; Chris Lever finance director; Sally Lipsius deputy head of TV; Steve Little senior copywriter; Jo Moore creative director; Simon Peck board account director; Jo Reid board planner; Tim Robertson creative director; Simon Robinson creative director; Mike Wells creative director.