CRH's upbeat results and outlook this week provided a marginal fillip for the share price but not enough to assuage fears of many over the increasingly two-tier structure of the Irish stock market.

However, before people offload the so-called old economy stocks - industrial heavyweights such as CRH which previously formed the backbone of the exchange - in favour of the fast-tracking dot com set, they should pause for thought.

The general consensus is that, at some stage, the bubble will burst for the dot coms. They may not sink but their valuations must surely come back to some reasonable multiple. In the meantime, investors can earn a decent income through dividends on these profitable, if unfashionable stocks.

Dominic Coyle can be contacted at dcoyle@irish-times.ie