Shares in Fincantieri dropped on Wednesday after the European Commission said it would review its deal to buy STX France.
The Italian shipbuilder's stock fell as much as 6.8%.
It was trading at EUR 0.93 later on Wednesday.
The Commission said on Tuesday it would closely investigate the proposed acquisition.
Ministers from France and Italy had pledged to push through the merger, which would see Fincantieri control half of STX France.
