Dublin-based Elan has completed the separation of a substantial portion of its drug discovery business (the Prothena Business) into a new independent, publicly traded company, Prothena. Incorporated in Ireland, Prothena commenced trading on the NASDAQ Global Market as of Dec. 21.

Elan shareholders on the register on Dec. 14, 2012, the record date, received one Prothena ordinary share for every 41 Elan ordinary shares held. In addition, a wholly owned subsidiary of Elan subscribed $26 million and received Prothena shares representing 18% of the total outstanding ordinary shares of Prothena. On completion of the transaction, Elan shareholders directly and indirectly own 100% of Prothena by virtue of their direct ownership of 82% of Prothena's outstanding shares and indirect ownership of 18%.