(Bloomberg News) News Corp.'s loss of $7 billion in market value over four trading days shows investor concerns that a probe into alleged phone hacking by journalists at one London newspaper could have a broader impact on the company.

Rupert Murdoch's New York-based media company tumbled $1.27, or 7.6 percent, to $15.48 in Nasdaq Stock Market trading yesterday, the biggest drop since April 2009. It was the fourth straight decline in the company's closing price, cutting its market value by 15 percent to $41.2 billion.

The slide is far out of proportion with the lost profits from closing the News of the World tabloid or from delaying the acquisition of the satellite-TV provider British Sky Broadcasting Group Plc, said David Bank, an analyst at RBC Capital Markets in New York. Investors are concerned about the scandal's effect on other News Corp. holdings, which include the Fox TV networks and film studios, the Wall Street Journal and three other newspapers in the U.K.

"There's a lot of noise out there," said Bank, who rates the stock "outperform" and doesn't own any. "These headlines cause massive swings in sentiment and stock price, leaving a cloud of uncertainty about how deep the allegations go."

The most immediate questions involve News Corp.'s $12.4 billion bid for BSkyB. Yesterday, U.K. Culture Secretary Jeremy Hunt said he will refer the proposed deal to the country's Competition Commission, which will spend at least six months on a review. That will be followed by "intensive discussions," Hunt told lawmakers in London.

'Reconsider' Bid?

U.K. Deputy Prime Minister Nick Clegg yesterday asked Murdoch to "reconsider" the BSkyB offer following allegations that News of the World tabloid hacked into voice mails of terror and murder victims and paid police for stories. U.K. Labour Party leader Ed Miliband told BBC Television the day before Murdoch should drop his buyout bid.

"It will be hard for the government to approve the bid, either now or at some point in the future," said Ian Whittaker, a London-based analyst at Liberum Capital.

News Corp., which already owns 39 percent of BSkyB, wants full control to gain access to the broadcaster's increasing cash flow. BSkyB may also help Murdoch make News Corp.'s newspapers more profitable by allowing him to bundle print and pay-TV subscriptions and spread content over media platforms.

In a statement yesterday, News Corp. said it still anticipates it can win regulatory approval.