Image copyright Getty Images Image caption The company’s US operations were expected to post a larger loss than its international operations
Amazon has seen revenue grow by 24% to $59.5bn (£48.3bn) in the last three months of 2018.
But the figure was slower than the 47% growth reported in the same period a year ago.
The Seattle-based company’s net losses widened from $2.5bn a year ago to $3.4bn, also helped by aggressive spending on its warehouses, equipment and staff.
Shares slipped 3% in pre-market trading.
We’ve previously forecast $59.5 billion revenue for the quarter. Revenue was $60.9 billion, below our forecast range of $63.5 billion to $64.5 billion. CEO Jeff Bezos
Revenue increased across all of Amazon’s lines of business – Amazon Web Services (AWS), consumer retail and advertising.
“Our growth was even better when you exclude currency headwinds,” chief executive Jeff Bezos said in a statement.
Amazon does not break out its AWS results. For the fourth quarter, AWS generated $3.6bn in revenue and an operating loss of $861m, the company said.
The online retailer opened nine new warehouses in 2018, compared with seven in 2017. Capital spending in the fourth quarter amounted to $7.2bn, compared with $4.9bn a year ago.
Amazon also confirmed a request made by some users last week that it reduce the price of its most popular Echo product by 6.9%.
However, the company stressed that the cut was the result of a “product mix” change which did not result in “any real material savings”.
Weakness in Europe and the US was partially offset by strength in Japan, Amazon said.
Image copyright Getty Images Image caption Amazon’s AWS business made $3.6bn in revenue for the company in 2018
International revenues were $37.4bn, compared with $34.8bn the previous year.
The company said international revenue growth rate slowed, versus the third quarter, partly because of one-off foreign exchange headwinds.
The holiday quarter is traditionally strong for Amazon as shoppers look to buy Black Friday and Cyber Monday bargains.
Image copyright Getty Images Image caption Amazon’s net losses widened from $2.5bn to $3.4bn, due to aggressive spending
Amazon is investing heavily in growth areas, including its Alexa digital assistant and its delivery service, Amazon Flex.
But the company also faces stiff competition from Amazon Prime service – which offers exclusive deals and delivery discounts.
It also sells luxury fashion brands such as Gucci and Ralph Lauren.
Amazon’s results come a week after supermarket group Walmart reported its own strong sales growth but a weaker profit after aggressive investment.
Amazon’s stock has climbed steadily over the past two years. Shares closed Monday at $1,885.20.