Shareholders at Elan Corp. risk losing US$2 billion on a takeover bid from Royalty Pharma. This was after the company's board rejected the offer from Royalty.

Royalty Pharma has made five modifications to its bid and boosted its unsolicited offer to as much as US$15.50 per share piece. UBS AG estimates a 28% fall to US$9.70 that would mean a wipe out of the supposedly US$2 billion market value.

Shareholders are set to vote next week on whether to endorse the sale to Royalty Pharma or support Elan's CEO Kelly Martin strategic plan to buy drug rights as an independent firm.

Last June 10, Elan announced that other suitors have emerged Royalty Pharma thinks that S&P Capital IQ is the only realistic option the company has. Leerink Swann LLC said that shareholders at Elan should accept the transaction offered by Royalty Pharma.

Royalty Pharma made a sweeter bid on June 7 to US$13 per piece share in cash. An additional US$2.50 share will be given after performance targets are hit. In less than four months, Royalty attempted four times to acquire Elan.