It was a prime holiday season for Amazon: The online retailing giant posted its biggest quarterly profit yet Thursday as it sold more voice-activated Echo devices and added more Prime members.

The Seattle-based company reported net income of US$1.9 billion ($2.5b), or $3.75 per share, in the three months ending December 31.

That blew past the $1.88 per share analysts expected, according to FactSet.

Revenue soared 38 per cent to US$60.5b in the fourth quarter, beating the US$59.8b analysts expected.

Advertisement Inc.'s stock rose more than 4 per cent in after-hours trading Thursday.

- AP