WPP stock drops as ad giant investigates CEO's behavior

WPP (WPP) shares declined after an announcement that the board is investigating an allegation of personal misconduct against the the CEO of the world's largest advertising agency, Martin Sorrell.

In early-afternoon Wednesday trading in London, WPP's share price was down 2.2 percent at 1,094 pence. Shares of WPP were also indicated to open lower in New York Stock Exchange trading. 

The Wall Street Journal reported the allegations involve possible misuse of assets and improper behavior.

No details were offered but WPP says "the allegations do not involve amounts which are material to WPP." Sorrell is one of Britain's highest paid executives, with The Guardian reporting that he's earned more than $280 million over the last five years. 

Sorrell, who has run WPP for more than three decades, noted the claim of financial impropriety and said he rejected "the allegation unreservedly," adding that he won't play any role in the management of the investigation.

Ian Whittaker, analyst at Liberum, says the allegations could "intensify" speculation about Sorrel's future as CEO.

The question of who might succeed Sorrell has been raised at the company's annual shareholder meeting, although the executive has never said when he might step down, The Guardian added.