Amazon has sacked workers it believes had been misusing internal data on high-selling products, the Wall Street Journal (WSJ) reports.
Amazon reportedly believed the staff, in India, China and the US, had abused their access to an internal database.
And some USB ports on desktop computers had since been disabled so no further data could be copied, the paper said.
Amazon said staff that broke its “high ethical standards” could be sacked or face legal action.
The WSJ said the sackings were part of a broad effort at Amazon to combat merchants trying to trick its systems into making their products more prominent.
About three million merchants are believed to sell their goods via Amazon.
Some tricks involve posting fake reviews, both good and bad, or filing lots of searches for products to spoof interest in them so Amazon’s algorithms flag them as being in demand.
The WSJ reports that Amazon had been investigating alleged attempts to bribe its staff.
Amazon has now reduced access to internal sales data and limited how many searches can be done on the database.
Amazon told BBC News it had “sophisticated systems to restrict and audit access” to its internal sales data.
“We hold our employees to a high ethical standard and anyone in violation of our code faces discipline, including termination and potential legal and criminal penalties.”
It said it also took action against “bad actors” and would delete accounts, withhold funds and remove reviews if it found they were abusing its system.