Oftringen: The Omya antitrust investigation began on 23 October 2026, when the European Commission opened a formal inquiry into whether the Swiss-based minerals group abused a dominant position in the supply of calcium carbonates to the European paper industry. The Commission says it will treat the case as a priority, and it has registered the file as AT.40893. Executive Vice-President Teresa Ribera called calcium carbonates key to Europe’s paper and cardboard industry.

Investigators in the Omya antitrust investigation will look at two kinds of conduct. The first is exclusive purchasing obligations, which would require customers to buy all or most of their calcium carbonates from Omya. The second is exclusivity rebates, which would give customers a financial incentive to do the same.

The concern is that these practices may have limited the ability of other calcium carbonate suppliers to compete for paper industry customers. A rival that cannot win a meaningful share of a buyer’s volume struggles to reach the scale it needs to keep investing. Customers, in turn, lose the chance to switch supplier or to play one offer against another.

The Commission describes Omya as the largest supplier of calcium carbonates in the European Economic Area and says the company may hold a dominant position there. It has not published a market share figure, and none of the public documents gives one. Calcium carbonates serve as fillers and coating pigments in paper, so they shape production costs and properties such as brightness, opacity, smoothness and printability.

The legal basis for the Omya antitrust investigation is Article 102 of the Treaty on the Functioning of the European Union and Article 54 of the EEA Agreement, which both prohibit the abuse of a dominant position. Under Article 11(6) of Regulation 1/2003, the formal opening also relieves national competition authorities of jurisdiction over the matter. The public reports do not say which Omya group company is the subject of the proceedings.

The opening of proceedings does not prejudge the outcome. The Commission has made no finding of infringement, and the presumption of innocence applies until a final decision. No statutory deadline governs the case, so its length will depend on its complexity and on how closely the companies cooperate.

The timing matters for the sector. Ribera pointed to the value of a competitive supply chain for paper and board, a point that gains weight as packaging users move toward paper. For paper mills and for smaller mineral suppliers, the Omya antitrust investigation will show how closely the Commission reads loyalty-inducing rebates in industrial supply contracts. Firms that rely on exclusivity clauses elsewhere in the paper chain will follow the Omya antitrust investigation for the signals it sends about what the Commission regards as acceptable commercial practice.