German drug and chemical maker Merck KGaA has made a cash bid for the takeover of domestic rival Schering AG in a multibillion-euro deal, Schering said Sunday.

In a brief statement, Schering AG said it had received an offer of 77 euros ($91.78) per share from Merck KGaA.

"After the information about the approach became public, the executive board of Schering AG stated that this offer significantly undervalues Schering and its prospects as an independent specialized pharmaceutical company," Schering said.

Though Schering did not term the bid hostile, it said the company "also confirmed the approach is unsolicited and that no negotiations are ongoing with Merck KGaA."

The statement gave no further details and a spokesman for Darmstadt-based Merck was not immediately available for comment.

Schering CEO Hubertus Erlen said he expects Merck to outline its offer on Monday and expressed dissatisfaction about the bid.

"We won't recommend shareholders to accept the offer," Erlen told Dow Jones Newswires.

According to an online report in Manager-Magazin.de, the approximately 130 Merck family members who own 73 percent of the company would float 20 percent of their shares on the stock exchange and use the proceeds plus 2 billion euros ($2.38 billion) in cash in the bid for Berlin-based Schering. The remaining 27 percent of Merck is already publicly owned.

Schering is currently worth around 12 billion euros ($14.3 billion), Manager-Magazin reported, saying the new company would have a market value of around 16 billion euros ($19.07 billion).

There has long been speculation that Schering may seek a merger with Merck KGaA or Germany's Altana AG, but Schering Chief Financial Officer Joerg Spiekerkoetter sought to dampen rumors last month, saying "neither company makes strategic sense to us."

Schering shares closed Friday at 66.86 euros ($79.69) while Merck shares were at 83.71 euros ($99.77).

Founded in 1851 as a pharmacy, Schering AG has since grown to a corporation that employs 24,500 people worldwide. Schering AG's connection to its former U.S. subsidiary, New Jersey-based Schering-Plough, was broken during World War II and the companies are no longer related.

Merck KGaA was also founded as a pharmacy, in 1668, and the company is the oldest pharmaceutical business in the world. It has been entirely separate from the New Jersey-based Merck & Co. since the end of World War I.

Merck KGaA employs some 29,000 people.