Citing concerns over counterfeits and “unacceptable business practices,” footwear manufacturer Birkenstock will no longer sell or authorize the sale of its products by other merchants on Amazon.com Inc.

The ban on Amazon sales takes effect Jan. 1, Birkenstock Americas CEO David Kahan wrote in a letter to Birkenstock resellers that was posted on and then removed from Scribd, a digital publications subscription service. The letter was obtained by CNBC and posted on its site.

“Amazon has made it clear that the only way to achieve a ‘clean’ environment (meaning no counterfeits and non-authorized sellers), is to sell our complete product offering to Amazon directly,” Kahan writes. “We believe this decision does not align with the long-term health of our brand or your business objectives.”

Kahan acknowledges that pulling Birkenstock products from Amazon and not allowing other merchants to sell its shoes and other products on the online marketplace, likely won’t stop the proliferation of counterfeit Birkenstock products on Amazon. “Sadly, after this policy change goes into effect, products marketed as ‘Birkenstock’ will likely still be offered on Amazon.com,” he writes. “By taking this course of action, we are, in effect, leaving the Amazon marketplace to counterfeiters, fake suppliers and unauthorized sellers with whom we have no relationships.”

Birkenstock’s decision to stop selling its products on Amazon may have been bold move, but one analyst says it wasn’t necessarily the right one.

“If anything, Birkenstock has more leverage working with Amazon than not engaging,” says Mabel McLean, director of commerce IQ at L2 Inc. “Not selling directly through Amazon isn’t going to impact third-party sellers selling their products. Unless you are one of the few brands that has a strategic relationship with Amazon, you don’t have any control over third parties selling on Amazon. Third-party sellers can list pretty much anything.”

A Birkenstock spokesman declined to comment further. Amazon, No. 1 in the Internet Retailer 2016 Top 500 Guide, did not return a request for comment on Birkenstock’s decision.