Amazon
The company's shares, already up nearly 41 percent this year, were down 2.6 percent at $1019 in after-hours trading on Thursday.
The shares touched a record high of $1083.31 in regular trading, helping chief executive Jeff Bezos unseat fellow tech billionaire Bill Gates to become the world's richest person, according to Forbes.
Amazon said operating expenses rose 28.2 percent to US$37.33 billion in the second quarter ended 30 June.
The company also forecast an operating income of US$300 million to a loss of US$400 million for the current quarter.
Analysts had expected operating income of US$931 million, according to FactSet.
Amazon is known for making bold investments in new business areas even at the expense of profits, a strategy that is often criticised by investors.
The world's biggest online retailer said net income fell to US$197 million, or 40 cents per share, from US$857 million, or US$1.78 per share, a year earlier.
Net sales rose 24.8 percent to US$37.96 billion.
Amazon, which is in the process of buying upscale grocer Whole Foods Market
Analysts had expected a profit of US$1.42 per share and revenue of US$37.18 billion, according to Thomson Reuters I/B/E/S.
(Reporting by Rishika Sadam in Bengaluru; Editing by Sriraj Kalluvila)