Advertising giant WPP has been dealt a further blow since Sir Martin Sorrell's exit after credit rating agency Moody's downgraded its outlook for the group.
Sir Martin's abrupt resignation on Saturday night saw shares in the group fall by almost 7pc on Monday as investors considered the future of the business without its founder.
Piling more pressure onto the FTSE 100 company, Moody's revised its outlook for the firm from stable to negative as a result of the 73-year-old's departure after markets closed on Monday night.
"Sir Martin's resignation comes at a time when the company is already facing a number of operational challenges," said Christian Azzi, Moody's lead analyst for WPP. "[It] introduces uncertainty over the strategy and ultimately the structure of the group going forward."
Moody's also flagged concerns over WPP's performance compared to rivals such as Omnicom and Publicis as well as its large net debt burden and its risk of losing major clients now its well-connected boss has gone.
WPP’s biggest client Ford, for example, is halfway through an agency review aimed at cutting costs, analysts at Berenberg warned before Sir Martin quit.
Moody's held the company's credit rating at Baa2, two levels above junk.
City analysts have said that a break-up of the business, which is made up of 400 separate companies, is now inevitable with its market research, public relations and health divisions the most likely assets to go first.
"This story is a tragedy because you're deconstructing what Sorrell has constructed," said Alex DeGroote, a media analyst at Cenkos Securities.
Sir Martin built his £20bn group through takeovers after acquiring a tiny shopping basket maker in the Eighties.
His exit followed an internal investigation into alleged misconduct, of which the details have not been released. Pressure is now mounting on the company to publish the claims, with Liberal Democrat leader Sir Vince Cable yesterday urging WPP to disclose the allegations.
One investor told The Daily Telegraph on Tuesday that shareholders have also been kept in the dark on the issue but had no plans to pressure the company for information. Sir Martin has denied wrongdoing.
The most likely internal candidates for the top job are tipped to be Mark Read, chief executive of WPP agency Wunderman, and Andrew Scott, WPP’s corporate development director, who were appointed joint chief operating officers on Saturday after Sir Martin resigned.
Sources said the pair unusually attended a board meeting on Friday, arranged before Sir Martin's exit, despite neither being on the eleven-person board.
Sir Martin is understood to be furious over the board's handling of the investigation, with a source close to him saying "in the end he thought ‘I’m 73 years old, I don’t need this s---'".
He was the longest serving chief executive of a FTSE 100 firm and one of the most successful businessmen in the world, but in his final year running WPP, investors grew impatient with the company's lack of growth. The advertising industry is facing challenges amid drops in advertising spend, the growth of social media platforms and fresh competition from consultants.
Harris Associates, one of WPP's largest shareholders, said at the weekend that the "circumstances surrounding this [Sir Martin's exit] are regrettable as is a leadership transition without Sir Martin’s direct involvement".
WPP shares closed down 0.6pc at £11.04 today.