For almost a decade, Amazon staff went undercover on Walmart, eBay and other marketplaces selling products under the guise of a company called ‘Big River.’ WSJ’s Dana Mattioli reports on the secret arm of Amazon that surreptitiously gathers intelligence on its competitors. Further Reading: -Inside Amazon’s Secret Operation to Gather Intel on Rivals  -Inside Amazon’s Push to Crack Trader Joe’s—and Dominate Everything  Further Listening: -TikTok Wants to Be More Like Amazon. Amazon Wants to Be More Like TikTok.  -What Is Amazon’s Secret ‘Project Nessie’?  Learn more about your ad choices. Visit megaphone.fm/adchoices