The European Commission said it is probing container-shipping companies for possibly fixing prices. The antitrust regulator is looking into how these firms announce their price increases. The method of making the announcements raised suspicions that the firms may have colluded with each other to hike the prices of some international trading routes.

The Commission did not name the companies that were being investigated, but a person familiar with the matter told The Wall Street Journal that there 14 firms from Europe and Asia that were targeted to be probed. The regulator did not cite examples on how the announcements could be used to rig prices, but the Commission said the firms had been making regular public announcements of their planned price hikes since 2009. The public notices are typically done in a successive manner, just a few weeks before the price increases take effect, the regulator said.

In a statement, the Commission said, "This practice may allow the companies to signal future price intentions to each other and may harm competition and customers."

The WSJ report said Denmark-based Maersk, France-based CMA CGM and Switzerland-based Mediterranean Shipping Co have announced price hikes simultaneously for three times this year. A fourth increase is set for December. However, smaller container firms that offer cheaper prices have challenged the price hikes by the top three container shipping companies in the world. The report said that as compared to the prices at start of the year, freight rates are still lower now.

In a statement, Maersk said it was told that it will be part of the investigation. However, the company also said that it was not given any reason to believe that Maersk Line did not follow EU competition law. Meanwhile, CMA CGM said it will cooperate with investigators fully but clarified that it complied with EU law in its price announcement practices.