In theory, Seller Fulfilled Prime (SFP) allows sellers to sell products with the Prime badge directly from their warehouse and enables Amazon to increase Prime assortment without building ever-more warehouse space. Most sellers use the Fulfillment by Amazon (FBA) service that instead stores products in Amazon warehouse to get the Prime badge. The company is increasing fulfillment capacity by 50% in 2020 to keep up with rising demand.

To improve performance, the company has introduced changes that, starting February 2021, will require sellers to use shipping methods that support Saturday delivery and pick-ups, have nationwide delivery coverage for all standard size delivery products, and meet targets for one and two-day delivery promises. The changes introduced will improve the overall on-time delivery metric. However, they will achieve that by reducing the number of sellers participating in the program and the number of products offered by them.