Amazon has published the figures for its Amazon Prime service for the first time, revealing that revenues for the subscription service have hit $6.4bn (£5.2bn).
This means the service, which allows customers to access premium video content and faster product deliveries, lags behind Amazon's retail and web divisions.
In 2016, Amazon Retail brought in $91.4bn and Amazon Web services made $12.2bn.
Revenue growth in Amazon had also slowed from 61.7 per cent year-on-year in 2015 to 43.1 per cent in 2016.
Joining Amazon Prime costs £79 for a year in the UK, and it is thought that the service now has 65m subscribers worldwide, as compared to 45m the year before.
Amazon's filing on the US Securities and Exchange Commission also revealed that it spent $103m on acquisitions last year, significantly less than the $690m it had splashed out in 2015, when it bought Twitch and Goodreads.