Negative sector news for building materials and residential housing in addition to a downgrading of Ryanair forecasts combined to push the Iseq into negative territory this afternoon.
At 12.35pm the Iseq was 46 points, or 0.76 per cent lower at €6,073.
Among the fallers was market heavyweight CRH, which is off over 2 per cent at €23.35, with analysts pointing to weak results from Cimpor, the Portuguese cement producer, as evidence of ongoing softness in the sector.
Also in negative territory this morning were Ryanair shares which had fallen over 3 per cent to €2.74 at the mid-point.
This morning Numis Securities cut its earnings estimates for Ryanair and EasyJet, Europe's two biggest discount airlines, citing the impact of higher fuel costs and slowing sales.
Among the financials Anglo Irish Bank stock was off 2.6 per cent at €8.59, while Bank of Ireland was 1.5 per cent lower at €7.95. Irish Life and Permanent shares were down 0.5 per cent at €11.
Leading the risers this afternoon was Elan, up 1.7 per cent to €16.20 and Grafton up 1.2 per cent to €4.89.
In Britain the benchmark FTSE 100 index advanced further in midday trade today as miners and oil stocks recovered after yesterday's decline.
By 11.39am, the FTSE 100 was up 29.2 points, or 0.49 per cent, at 6,097.9, but still some 4 per cent below a four-month peak reached on May 19th.
Oil heavyweights BP and Royal Dutch Shell led the advance, up 2 per cent and 1.7 per cent respectively as oil prices remained above $130 a barrel, although analysts cautioned that a more protracted decline may be imminent as demand falls.