Online retail giant Amazon has said it prevented four billion bad listings from making it onto its site and got rid of more than three million counterfeit products last year.

The firm’s second Brand Protection Report shows a mixed picture over tackling counterfeiters compared with 2020, when Amazon blocked 10 billion listings and got rid of two million fake products.

The Seattle-based e-commerce juggernaut also saw a decrease in complaints of intellectual property infringement in 2021 while growing the number of active brands on its site.

According to the report, Amazon stopped more than 2.5 million attempts to create fake accounts on its third-party marketplace, where sellers can list their products directly to consumers.

That number is about a 58% decline from the attempts it said it stopped in 2020, which the company credits to its vetting process and other efforts to deter bad actors.

But Juozas Kaziukenas, the founder of e-commerce research firm Marketplace Pulse, said it can be hard to independently know what actually caused those declines – whether it is Amazon’s policies or other factors.

Counterfeit sellers have long plagued Amazon and other e-commerce retailers, including eBay. Amazon has stepped up efforts to fight it in recent years amid heightened scrutiny from brands and legislators pushing for anti-counterfeit legislation.

Amazon backs a US version of an online retail bill, known as the INFORM Act, which would require online marketplaces to collect contact and financial information from high-volume sellers and disclose some of the information to consumers.

The firm had opposed an earlier US senate version of the bill, which would require online retailers to gather information from a larger group of third-party merchants.

Meanwhile, TechNet, a lobbying group that counts Amazon and eBay as some of its members, is pushing back against another bill that would make the e-commerce platforms liable for counterfeit goods sold on their site.

An Amazon spokesperson said in an emailed statement the company recognises “the intent of the legislation is to stop counterfeits” and looks forward to working with US congress to achieve that goal.

In its report, Amazon said it implemented a scheme last year that made it harder for bad actors to register for selling accounts by requiring one-on-one conversations with a company team member to verify their identity.

It says it is also verifying the seller’s physical location and payment instruments and leveraging machine learning to detect risks about potential accounts.

Last year, the company said it spent more than 900 million dollars to push back against fraud, and sued – or referred – more than 600 sellers for investigation in the US and other places like China.

Amazon did not reveal in the report the source of most counterfeit products, but China has been a sore spot.

And the company will not share data that helps it detect and prevent fake products from showing up on its site, said Mary Beth Westmoreland, Amazon’s vice president of brand protection.