Smartphone giant Samsung has been accused of paying people to write bad reviews of rival smartphones.
Fair-trade officials are investigating reports that Samsung Taiwan paid people to criticise HTC phones online - and write positive reviews of Samsung ones.
If Samsung is found guilty it could be fined more than £500,000.
Samsung Taiwan said it has "ceased all marketing activities that involve the posting of anonymous comments".
Samsung, based in South Korea, said the "unfortunate incident" had gone against the company's "principles".