Grappling with slowing sales growth and rising costs, Amazon.com is squeezing more money from the nearly 2 million small businesses that sell products on its sprawling online marketplace.

For the first time, Amazon’s average cut of each sale surpassed 50% in 2022, according to a study by Marketplace Pulse, which sampled seller transactions going back to 2016.

The research firm calculated the total cost of selling on Amazon by tallying the commission on each sale, fees for warehouse storage, packing and delivery, as well as money spent to advertise on a site where hundreds of millions of products jostle for attention. Paying Amazon for logistics services and advertising is optional, but most merchants consider these a necessary part of doing business.