For a lot of Irish high-technology companies, the prospect of a Nasdaq flotation is enough to make directors drool. A company can float on huge earnings multiples, directors can make lots of money and there are thousands of investment funds apparently willing to sink their money into virtually any high-tech company with a tale to tell.

But then we had the CBT affair where bad news wiped 90 per cent off the value of the Irish software company, directors stepped down and the company's founder, Bill McCabe, came back to try and resurrect the company - after selling $40 million (#37 million) worth of shares a few months before they collapsed.

Other Irish high-tech stocks have suffered from the unpredictability of the Nasdaq investor, with Elan knocked back by 25 per cent in the past three weeks on fears over the timetable for the launch of the Ziconotide pain-killing drug. Just yesterday, Iona shares plummeted after a profit-warning for the first quarter.

It has been a bad week for Irish firms on Nasdaq. Before Iona's tribulations yesterday, ICON, the clinical trials high-flier was decimated by the market after sounding a profits warning on Tuesday that said earnings growth would be no more (our emphasis) than 30 per cent and that earnings growth next year would be non-existent.

ICON's value on the market was duly more than halved in colossal share volumes - 50 times the daily average - as spooked investors rushed to sell. Wall Street, and Nasdaq in particular, is an unforgiving place - and those high multiples that are commonplace on Nasdaq result from high expectations among investors. Any unpleasant surprises mean that the share price gets hockeyed unmercifully.

And to top that there are the notoriously long memories of the typical Nasdaq investor. ICON's Peter Gray is probably very over-optimistic when he says it will take a few quarters' trading before ICON's reputation (and rating) in the market is restored. Given how slow the CBT share has been to recover - despite the return of Bill McCabe and Greg Priest - it will take a lot longer than a couple of quarters before ICON recovers.

For all that, the reaction on Nasdaq on Tuesday to ICON's profits warnings was grossly exaggerated, and it is simply laughable that a profitable company like ICON can see its value more than halved in the space of a few hours. But then, those are the sort of chances any Irish company aspiring to a Nasdaq listing has to accept.