Craigslist countersued its minority owner, eBay Inc., on Tuesday, alleging the online auctioneer is competing illegally with the classified advertising Web site.
Craigslist's complaint, filed in Superior Court in San Francisco, claims eBay broke laws in a series of actions relating to its own classifieds site Kijiji, which launched last year in the U.S.
EBay calls Kijiji the "Craigslist killer," the complaint claims.
EBay named a representative to Craigslist's board who was a Kijiji insider and asked for confidential Craigslist information for the benefit of Kijiji, actions Craigslist claims violate California laws against unfair competition.
EBay also engaged in business interference, false advertising, phishing attacks, trademark infringement and trademark dilution and broke its duty to shareholders, the complaint alleges.
It infringed Craigslist's trademark by placing misleading ads for Kijiji on Google using Craigslist's name, the complaint said.
San Jose, Calif.-based EBay said it would respond to the allegations, but did not specify when.
Craigslist, based in San Francisco, wants eBay to return all shares acquired for the purpose of unfair competition, and pay damages.
EBay bought a 28 percent stake in Craigslist in 2004 from an unnamed former shareholder who solicited outside bids.
EBay sued Craigslist in April alleging Craigslist founder Craig Newmark and Chief Executive Jim Buckmaster engaged in a series of "clandestine transactions" intended to dilute its stake unfairly.