Visitors inspect a model Airbus SE A380 aircraft in an exhibition center at the aircraft maker's factory in Toulouse, France, on Wednesday, March 20, 2019.

A selection of major European firms saw their share price sink Monday following reports that the World Trade Organization has granted President Donald Trump the right to slap billions of dollars in tariffs on EU imports.

If confirmed, the WTO's decision would be to compensate the U.S. for what Washington has long argued are illegal subsidies enjoyed by the European plane maker Airbus.

Both Politico and Reuters reported that the ruling has been made in the U.S.'s favor, meaning levies can soon be imposed on certain goods.

When contacted by CNBC, a media spokesperson for the WTO said the organization was not yet commenting as the case remained live and details had to remain confidential.

The final ruling will mark the end of a complaint first brought by the United States in 2006.

A European Commission spokesperson told CNBC via email on Monday that it did not comment on leaks but added that the EU had "consistently communicated to the United States that the European Union is ready to work on a fair and balanced solution for our respective aircraft industries."