Rampant counterfeiting among Amazon Marketplace sellers is holding the retailer back. There are companies that simply won’t agree to sell their merchandise on the site, given the the company’s known issues with counterfeits, and the concern that genuine and knock-off merchandise could be co-mingled in Amazon warehouses. The online retail giant is now preparing a very public war on counterfeit merchandise.

Bloomberg Technology reports that Amazon plans to escalate its efforts in 2017, but kicked things off this year with new policies requiring some sellers to pay up to a $1,500 fee for each major brand that they sell. The company’s logic is that small-time counterfeiters who plan to quit the site after receiving a few complaints won’t want to register and pay a fee, but legitimate sellers that plan to stick around will be happy to.

One recent stand against counterfeits on the site came not from Amazon, but from Apple. The tech company was concerned about consumer safety as well as its trademarks: counterfeit products, the company noted, are “not subjected to industry-standard consumer safety testing and are poorly constructed.” Apple sued the makers of almost 100 products masquerading as its own on Amazon.

What makes Amazon an especially good marketplace for counterfeit goods is that it’s easy to register and get started selling, and buying something on Amazon gives online shoppers a certain amount of confidence in the transaction.

“Amazon is the most trusted marketplace in the world. That in and of itself attracts this nefarious element because they know shoppers go there and trust what they are buying is genuine,” a representative of NetNames, a company that helps brands figure out where their counterfeits are being sold.

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