The ISEQ index of Irish shares fell 17.87 points to 9625.54 in morning trade today.
Aer Lingus saw a positive move, up 8c to €2.64, after the airline said it would investigate a stoppage by ground staff at Dublin Airport last weekend.
The staff refused to work when they were asked to man check-in desks and boarding gates. The protest caused flight delays of up to two hours.
Management at the airline has written to unions describing the action as 'totally unacceptable'. SIPTU insists it was not an official dispute.
Drinks and snacks group C and C recorded a similar change in share value this morning, but in the other direction, by losing 8c from their share price.
Tullow Oil added 6c to yesterday's gains after its announcement of a very significant oil find of oil in Ghana, Africa. Tullow is currently trading at €6.76.
The discovery of up to 600 million barrels of light oil were far ahead of the 300 million barrels the firm had forecast.