Arbitron shareholder Joseph Pace has filed a lawsuit asking a judge to halt the sale of the ratings company to Nielsen, claiming that a breakup fee and other terms of the deal prevent any competing offers to buy the company. Bloomberg reports that Pace's suit claims that Arbitron's break-up fee of $32.7 million and a provision in confidentiality agreements signed by other bidders "ensure any legitimate bidder has been effectively shut out of the process." The lawsuit was filed in Delaware Chancery Court in Wilmington, DE.

Pace is asking the court to stop Arbitron from closing the deal with Nielsen, until the company adopts procedures that will "obtain the highest possible price for shareholders."

In December, Nielsen announced it had signed a definitive agreement to acquire Arbitron for $48/share in cash.