Amazon’s global net profits plummeted to $7m (£4.5m) in its second quarter, despite sales soaring 29% to $12.83bn (£8.18bn) as it continued to invest in its business.

Profits took a $65m (£41m) hit in relation to the acquisition and integration of automated picking firm Kiva Systems. In the second quarter of last year profits reached $191m (£121m).

International sales, which includes the UK, German, Japanese, French, Chinese, Italian and Spanish sites, were up 22% to $5.51bn (£3.51bn) over the quarter.

Amazon’s Kindle and books for the device dominated the best-seller list for its UK site. The Fifty Shades trilogy was the top-selling e-book. Author of the erotic novels EL James became the first author to sell more than a million books on the Kindle store.  

The online giant expects to make a loss at an operating level between $350m (£223m) and $50m (£32m) in the third quarter, down from a $79m (£50m) profit last year. Despite the predicted profits plummet it expects to grow global sales between 19% and 31%, to between $12.9bn (£8.2bn) and $14.3bn (£9.1m).