Amazon Prime amassed millions of new subscribers in 2015 after the company expanded its range of features on offer to paid-for memberships.
According to Consumer Intelligence Research Partners, Prime now has 54 million subscribers in the US, with 47 per cent of all Amazon customers now signed up to the pay service.
For Black Friday last year, Amazon cut the price of Prime by £20, bringing it down to £59 for the year rather than the £79. It also gave Prime members 30-minute early access to Lightning Deals.
Amazon said it added three million worldwide customers to Prime in the first three weeks of December, following Black Friday. In reference to its total subscribers, it said it had "tens of millions of members worldwide."
Prime gives customers free one-day delivery and access to one-hour delivery in both London and Birmingham. It also includes Prime's film and TV content, books, music, access to Prime Instant Video and unlimited cloud photo storage.
The user report released this week said that seven million of the 14 million new US sign-ups in 2015 were added in the last quarter of the year.
The results come ahead of Amazon’s earnings report this week.
This year, Amazon is set to expand its range of services to further household groceries and goods, offering new product lines through its Pantry service.