Hoechst and Rhone-Poulenc had announced last December they would merge to create an international drugs giant spanning pharmaceuticals, agricultural chemicals and animal health products.

Rhone-Poulenc said it would offer one share for 1.333 Hoechst shares and that the offer would run through November 26. Hoechst shareholders also would be eligible for a special dividend of 2.72 euros in December, subject to the success of the exchange offer as well as a German tax credit of .17 euros per share.

If the offer is successful, Rhone-Poulenc plans an extraordinary meeting on December 15, where it will ask shareholders to approve the capital increase for the offer and a change in the company's name to Aventis.

Aventis shares would then be listed on the Paris and Frankfurt stock exchanges December 20, along with Aventis American depositary shares on the New York Stock Exchange.

Hoechst shareholders in July voted overwhelmingly in favour of forming Aventis, a huge drug and agricultural chemical conglomerate to be headquartered in Strasbourg, France.