Business Insider has contacted Amazon and eBay for comment.
EBay has filed a lawsuit against Amazon, accusing the United States retail giant of using illegal tactics to recruit sellers. Plus, the representatives reportedly admitted through messaging that they knew they were breaking the rules. eBay's user agreement prohibits people from using its private messaging system to trade outside information and to promote sales outside of the website.
The lawsuit, filed in Santa Clara County in California, accuses Amazon of having "perpetrated a scheme to infiltrate and exploit eBay's internal member email system" over the past few years.
eBay first accused Amazon of unlawfully poaching its sellers in early October.
eBay also says some of the Amazon representatives were successful in poaching sellers, openly discussing their exploits with those they were targetting. The company has said it was investigating EBay's allegations, which came to light this month after the internet marketplace's lawyers sent a cease-and-desist letter to Amazon.
Ebay says it wants to stop Amazon misusing its messaging platform and to pay it an unspecified sum. If a jury finds Amazon guilty of violating the California Comprehensive Computer Data Access and Fraud Act, the online retail giant could also be hit with restrictions on how it operates. These sellers are critical to both businesses, since the companies make billions of dollars in commissions on these sales.
Both eBay and Amazon rely on independent sellers to boost their revenue, but it's become a big part of Amazon's growth: past year, for the first time, more than half the items sold on Amazon were from third-party sellers.