Online flea market eBay is facing a class action lawsuit in California over allegations that its PayPal subsidiary has sought to improperly monopolise the forms of payment that sellers can use on the auction site.
EBay warned shareholders of the pending suit in a regulatory statement filed Wednesday. The plaintiffs are seeking treble damages and an injunction.
EBay regularly reviews the payment options available on its Website and runs a blacklist of prohibited payment vehicles. In June last year it added Google Checkout - the rival Internet payment service from the Web search giant - to the probited list.
EBay warns that sellers offering buyers the option of using any of the blacklisted payment services could see their listings cancelled and accounts suspended.
The online auctioneer is also facing claims against its ticket subsidiary StubHub for allegedely printing receipts which contain more than the last five digits of credit card numbers.
In the SEC filing, eBay responded: "We believe that we have meritorious defenses and intend to defend ourselves vigorously."