06:35 AM EDT, 06/04/2025 (MT Newswires) -- European Union antitrust authorities are intensifying their probe into Visa (V) and Mastercard ( MA ) , sending detailed questionnaires to retailers and payment firms to assess concerns about opaque fee structures, Reuters reported Wednesday, citing documents.

Regulators are exploring whether clearer, standardized fee summaries -- categorized by type and written in plain language -- could help address longstanding complaints from merchants and payment providers, the report said.

The EU is also examining whether fines issued by the card networks should be invoiced separately, making it easier for businesses to understand and challenge them, the report said.

The latest round of 11-page questionnaires, sent out on Tuesday, suggests that the investigation has progressed, with responses due by June 18, the report added.

Visa and Mastercard ( MA ) did not immediately respond to MT Newswires' request for comment.

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