THE French advertising giant Havas is on the verge of losing two key accounts worth an estimated $800m (£415m), a setback that could seriously undermine its defences against Vincent Bollore, the French corporate raider who is stalking the company.

The expected loss of the Intel and Volkswagen accounts is likely to weaken Havas at a time when Bollore has restructured his media holdings to leave him with a £140m war chest. He has been circling the French company for the past year and holds a 20% stake.

The loss will also raise the stakes between Bollore and Alain de Pouzilhac, Havas’s chief executive. De Pouzilhac is thought to have taken a personal involvement in retaining the Intel account.

Last summer Intel announced it was reviewing its advertising requirements. The American chip group is thought to have selected Interpublic, Omnicom and WPP to contest the final round of bidding for the $300m account.

The $500m German carmaker’s account covers the Volkswagen and Audi advertising business in America. Analysts said the company is planning to consolidate its advertising with its global agency, Grey, part of WPP.