EU authorities are accusing General Electric, German drugmaker Merck and electronics manufacturer Canon of violating European rules to push through mergers or acquisitions.
The EU Commission said Thursday it has filed complaints in all three cases, amid increasing European efforts to crack down on abuses.
While the Commission is not seeking to annul the mergers, it is threatening hefty fines if further investigation confirms wrongdoing. And EU Competition Commissioner Margrethe Vestager warned Thursday that authorities could seek to unwind mergers in the future if companies continue to deceive or mislead authorities.
Based on preliminary investigation, the Commission says it suspects GE failed to provide full information about its wind products ahead of its $1.6 billion acquisition of Danish energy company LM Wind this year.
GE could face fines of up to 1 percent of annual revenue. Based on GE's 2016 revenues of $123 billion, that could mean up to $1.2 billion in fines.
GE promised in a statement to cooperate with the investigation, saying: "We believe we acted in good faith to meet the EC disclosure requirements and there was no intent to mislead. When informed of the EC's concerns, we acted quickly and openly to resolve the issue."
Germany-based Merck KGaA, a separate company from the U.S. firm of the same name, is suspected of giving incorrect or misleading information about an innovation project ahead of a 2015 takeover of Sigma-Aldrich. Merck could also be fined up to 1 percent of annual revenue.
Merck also said it acted in good faith and expressed confidence in a statement that "this issue will be resolved in a satisfactory manner."
Japan-based Canon faces potential fines of up to 10 percent of annual revenue on suspicions it acquired Toshiba's medical equipment leasing company last year before seeking EU approval.
Canon said it would study the Commission statement but would not further comment.
The EU recently fined Facebook 110 million euros over its acquisition of WhatsApp and Vestager made it clear that such investigations will continue.
"It is an extreme step to undo a merger approval," Vestager said. "But I don't think one can say it will never happen."
When companies "jump the gun" and merge without approval, Vestager said, "competition could be harmed beyond repair."
After Thursday's announcement, the companies can seek a hearing to present their cases. There is no specific time frame for the completion of the investigation.