Paul Barrett, a minibus hire firm boss from Stanley, County Durham, has been convicted of bidding against items he was selling on eBay in order to drive up final prices.
Barrett, 39, was found guilty of ten offences under consumer protection laws passed in 2008 and 2009 to bring UK law up to European Union standards. He pleaded guilty and said he did not realise bidding against himself was illegal.
Each offence could earn Barrett a fine of up to £5,000. He will be sentenced later.
North Yorkshire Trading Standards began investigating after he sold a minibus which had had its mileage reduced illegally. They found he was selling goods using the name "shanconpaul" and then bidding up prices using the name "paulthebusman".
eBay welcomed the conviction and said it spends over £6m a year on countering fraud on the site. ®