How fickle the favours of investors? In the case of those in the US, the answer is very, as Athlone-based Elan pharmaceuticals found to its cost this week. Despite the release of impressive third-quarter figures, company bosses could do nothing as investors, fearful for the future, wiped more than 18 per cent off the firm's value in less than one session.

And the cause of the alarm? The group's admission that approval for a migraine drug it had hoped to have on the market next year would be delayed. In truth, the problem was not so much the delay as investor concern over management in a company which has twice failed to meet deadlines on drug delivery this year due to run-ins with the all-powerful US Food and Drugs Administration.

Still, it was a somewhat heavy-handed response to cut by a fifth the value of a company which has just reported $92.5 million (€90.2 million) in third-quarter pre-tax profits over a delay expected to cost $12 million in net profits over the whole of next year.