It's been a week of hard learning for Irish companies on the Nasdaq index in the US. First, ICON got clattered on the back of news that profits were going to fall short of expectations.

The clinical trials outfit is looking at stagnant profits for the next couple of years and paid the price with hard-nosed investors halving the value of its stock.

Just when it seemed things could get no worse, Iona Technologies, one of the star performers of the Celtic Tiger, was decimated following a similar profit warning.

Market analysts were unforgiving of the excuses put forward by the company for profits which it predicted would be below first-quarter expectations.

"Internal challenges" was the euphemism presented by Iona for a situation which the market read as a company beyond the control of its management in certain respects. Dealers reacted again by slashing the value of the stock in half. Both companies got a first-hand lesson in the harsh realities of life in the fast lane of a bull market where high multiples are the rule.

While they may well recover, their experience may yet prove salutary to the raft of young Irish high-technology outfits tempted by the prospect of fast funding via the technology-laden US index.