Amazon posted profits of $92 million for its second quarter ending 30 June 2015, a stark contrast from the same period last year when the e-tailer made a loss of $126 million.

Meanwhile,  sales increased 20% to $23.2 billion, compared with $19.3 billion in the second quarter of 2014.

The results caught traders off guard and the e-tailer's share price increased following the results. Amazon's share price of over £250 billion resulted in it pushing past Walmart to become the highest-valued retailer on the US stock market.

“The teams at Amazon have been working hard for customers,” said Jeff Bezos, founder and CEO of Amazon.com.

Amazon's chief financial officer Brian Olsavsky said the company's top line growth is being fuelled by the adoption of Amazon Prime.

Amazon has been heavily marketing its Prime membership service because those customers who spend £79 per year to receive next-day delivery among other benefits, are likely to spend over twice as much money as regular customers.

The company held its first ever Prime Day exclusive sales event on 15 July 2015, where Prime members ordered 34.4 million items, which broke Amazon's Black Friday record.

As well as tempting customers with the promise of more deals than Black Friday, Prime Day encouraged potential members to sign up to its Amazon Prime membership service at a discounted rate.