However, the organization is closely monitoring the situation and said it was not ruling out the possibility of an explosive subglacial eruption, leading to "an outburst flood and ash emission." The country's Civil Protection Authority announced Wednesday it was evacuating the area north of the volcano as a safety measure.
Read MoreUS government pushes for in-flight cell call ban
"Although this is an early warning and clearly a lot will depend on whether there is an eruption, wind patterns etc., investors will be concerned for trading and earnings," Robin Byde, a transport analyst at Cantor Fitzgerald, said in a morning note on Wednesday.
Loss in revenues
Transport stocks on the pan-European Euro Stoxx 600 Index pushed lower Wednesday, pushed by weak sentiment in the wider markets. Drifting ash clouds from volcanoes have the potential to disrupt flights, meaning cancellations and loss in revenues. Airlines, not to mention holidaymakers, will only be too aware of the problems posed in 2010 when Iceland's Eyjafjallajokull volcano shut down much of Europe's airspace for six days.
At the time, The International Air Transport Association estimated that the financial impact on airlines would be in excess of $200 million per day in lost revenues. It finally settled on a final figure of $1.8 billion in lost revenue and said that 10 million passengers and 100,000 flights were affected during the period. Within nine days of the eruption the European travel and leisure sector had lost 13 percent of its value, before facing an extremely volatile trading period for a further two months. Byde noted on Wednesday that European airline stocks have already seen some weakness in recent months and this would limit further falls if the ash clouds do materialize.
Read MoreAmerican Air scraps some first-class meals
And it's not only European airlines that could be affected. The volcano's location means that U.S. carriers flying trans-Atlantic routes could also be affected. Byde covers several international airlines and said that the eventual impact on earnings after the 2010 eruption was a "fairly modest" $80 million of operating profits across five airlines that year. Rorrie Mars, a U.S. transportation analyst at Atlantic Equities, said United Continental has the greatest exposure to these events as it generates 16 percent of its revenues from Atlantic flying. This is followed by Delta at 15 percent and American Airlines Group at 10 percent of revenue. Mars also said Delta's Atlantic traffic declined 5.5 percent year on year in the reporting period when the 2010 eruption happened, costing $5 million a day, which he added was a relatively small impact.