Pharmaceutical company Élan says it is facing an 'informal' inquiry by US regulators into trading in its shares.
The probe by the US Securities and Exchange Commission covers the period around the announcement on 28 February that sales of its Multiple Sclerosis drug, Tysabri, were being suspended.
Élan shares plummeted by around 70% after that announcement.
Élan and its partner, Biogen, suspended sales after a patient died from a rare brain disease known as PML while participating in a trial of Tysabri in combination with Biogen's Avonex drug.
