Amazon has announced a third-quarter loss of £273 million.
It is a significant increase on the £25.5 million the company was losing in the same period last year.
Amazon is also expecting to announce large losses in the next three months.
Its share prices crashed by more than 10% in after-hours trading in New York.
Amazon has been spending heavily in various new initiatives, including its Amazon Fresh grocery delivery service in the US, and its $1bn acquisition of video game streaming site Twitch.
Shares have fallen in the company by 20% since the start of the year.
