Amazon profit leapt by 46 per cent, but it wasn’t enough to satisfy investors who had expected a larger jump and sent the online retailer’s shares sharply lower in after-hours trading.

Amazon said Thursday it earned 207 million dollars in the second quarter, up from 142 million dollars a year earlier. Sales surged 41 per cent to 6.57 billion dollars, led by a 69-per-cent rise in electronics sales. Sales of media including books, DVDs, video downloads and CDs rose 18 per cent, Amazon said.

Amazon has been upbeat about sales of its Kindle electronic book reader, announcing this week that sales of electronic books had for the first time exceeded sales of hardcover books.

“We’re seeing rapid growth in Kindle, Amazon Web Services, third-party sales and retail,” Amazon chief executive Jeffrey Bezos said.

“We’re also encouraged by what we see in mobile. In the last 12 months, customers around the world have ordered more than 1 billion dollars of products from Amazon using a mobile device.”