The ISEQ index plunged 5.78% today, closing down 160.75 points to 2,620.12.
The fall mirrored stock markets worldwide as dismal housing data from the US fuelled fears of a slowdown in global economic recovery.
Aer Lingus, which today posted €19m losses for the six months to end June, closed down 4c to €0.89,
Elsewhere, CRH closed down €2.32 or 16.58% to €11.70; Kingspan was down 33c to €5.04; Aryzta shed 87c to €32.04; Elan Corp slipped 12c to €3.60; Paddy Power was down 74c to €26.00; Smurfit Kappa shed 16c to €6.80 and Tullow Oil was down 27c to €15.68.
Financial stocks were mixed, with AIB down 3c to €0.80, Bank of Ireland slipping 3c to €0.75 but Irish Life & Permanent up 1c to €1.53.
On the risers' board, Kerry Group added 20c to €24.75.