(Bloomberg) — Brazil’s antitrust regulator opened a probe into major soybean traders, saying an agreement focused on preventing deforestation in the Amazon forest raises the possibility of a purchasing cartel in the grain-export market. 

The probe is directed at 30 soybean traders and two industry associations. The group includes units of Cargill Inc., Archer-Daniels-Midland Co., Bunge Global SA and other companies that comprise the so-called Soybean Working Group, the agency Cade announced on its website Monday. 

The investigation stems from a moratorium signed by the group that publicly commits to avoiding soybeans from land deforested in the Amazon after 2008. While the companies say the agreement seeks to protect the rainforest, Cade said it constitutes an “anti-competitive agreement.” 

The antitrust body ordered that work on auditing farmers and sharing information on compliance should be suspended, effectively putting the moratorium on hold. Companies are still allowed to proceed with their own checks, said Lisandro Inakake, a manager at consultancy Imaflora who is also part of the soybeans working group.

The probe is significant as Brazil prepares to host the COP30 climate summit in Belém in November. The agricultural powerhouse, whose top product is soybeans, is facing international pressure as farming and cattle breeding are the main causes of deforestation in the country. 

Potential fines for the associations targeted could reach up to 2 billion reais ($365 million), according to Cade’s announcement. For the companies, it could be up to 20% of gross revenue from the last fiscal year. 

Cargill didn’t immediately reply to emails seeking comment, while ADM and Bunge directed comments to industry association Abiove, which was also listed in the probe.

Abiove said in a statement the moratorium is a pact that has been “recognized as a public environmental policy by the Federal Attorney General’s Office.” It added it would “collaborate fully and transparently with the competent authorities.” 

Farmers have long disputed the so-called Soy Moratorium because they believe the agreement between traders imposes stricter rules than the country’s own legislation, which allows landowners in the Amazon to grow crops on up to 20% of their land. 

The antitrust process started after requests by Brazil’s Lower House and Senate, the national agriculture confederation known as CNA, and the soybean farmers association of the largest grains producer state Mato Grosso, known as Aprosoja. 

“For years, a private agreement with no legal backing had been imposing unfair trade barriers on producers, especially small and medium-sized ones, preventing the sale of crops grown in regular and licensed areas,” Aprosoja Mato Grosso said in a statement.

–With assistance from Megan Durisin.

(Adds details on moratorium suspension and comments from farmers’ group Aprosoja.)

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