Amazon said Tuesday that Jeff Bezos is stepping down as CEO later this year, a role he's had since he founded the company nearly 30 years ago.

Amazon said he'll be replaced in the fall by Andy Jassy, who runs Amazon's cloud business. Bezos will then become the company's executive chairman.

Bezos founded Amazon as an online bookstore and turned it into a behemoth that sells just about everything. In the process, he became one of the world's richest people.

Amazon.com Inc. (AMZN) on Tuesday reported fourth-quarter earnings of US$7.22 billion.

On a per-share basis, the Seattle-based company said it had profit of US$14.09.

The results surpassed Wall Street expectations. The average estimate of 15 analysts surveyed by Zacks Investment Research was for earnings of US$7.05 per share.

The online retailer posted revenue of US$125.56 billion in the period, which also beat Street forecasts. Fifteen analysts surveyed by Zacks expected US$120.36 billion.

For the current quarter ending in April, Amazon said it expects revenue in the range of US$100 billion to US$106 billion. Analysts surveyed by Zacks had expected revenue of US$95.71 billion.

Amazon shares have risen 4 per cent since the beginning of the year, while the Standard & Poor's 500 index has climbed 2 per cent. In the final minutes of trading on Tuesday, shares hit US$3,387.74, a rise of 69 per cent in the last 12 months.