ConAgra Foods Inc. on Tuesday gave Ralcorp Holdings Inc. a week to start talking about its takeover proposal.
The ultimatum sent Ralcorp's shares down $7.68, or 9 percent, to $77.46 in aftermarket trading.
ConAgra, which owns brands like Chef Boyardee, Orville Redenbacher's and Healthy Choice, repeated its latest bid for $5.17 billion cash, or $94 per share. The Omaha-based company says Ralcorp, of St. Louis, has until 5 p.m. Monday to start discussions or it will walk away.
Ralcorp has rejected several bids from ConAgra since March, including turning down the $94-per-share offer last month.
A Ralcorp representative could not immediately be reached for comment. The company has said its plan, announced in July, to spin off its Post cereal business to focus on its private-label foods business will provide better value for its shareholders.
But ConAgra maintained that its offer is the better deal.
"Since Aug. 12, ConAgra Foods has heard from many of Ralcorp's shareholders who are urging Ralcorp to enter into negotiations with ConAgra Foods," the company said in a statement. It claims to have made several attempts to enter discussions with Ralcorp since March, including sending a presentation to its board.
"Ralcorp has continued to refuse ConAgra Foods' attempts to engage privately and hold a constructive discussion regarding the strong value, strategic logic and certainty of its proposal."
ConAgra cannot launch a hostile takeover bid, because Ralcorp adopted a shareholder rights plan, also known as a poison pill, in May. The company said Tuesday it believes it would achieve better value by combining the whole of Ralcorp into its business, rather than buying either of the company's units on their own.
A Ralcorp representative could not immediately be reached for comment.
ConAgra shares slipped 12 cents to $23.94 in late trading.