SEATTLE (AP) — Amazon's profit and revenue both grew in the latest quarter but its results fell below what Wall Street was expecting and shares of the world's biggest online retailer tumbled.

Amazon has long focused on spending the money it makes to grow its business and expand into new areas, from movie streaming to e-readers and even grocery delivery.

Investors have largely forgiven thin profit margins and zeroed in on the company's solid revenue growth and long-term prospects. It posted losses in two previous quarters due to rising operating costs.

Amazon said Thursday that it earned $239 million, or 51 cents per share, in the October-December period, which included the key holiday shopping period. That's up from $97 million, or 21 cents per share, in the same period a year earlier.

Revenue grew 20 percent in the fourth quarter, to $25.59 billion from $21.27 billion.

Analysts were expecting earnings of 74 cents per share on revenue of $26.05 billion, according to FactSet.

For the current quarter, Amazon is forecasting revenue of $18.2 billion and $19.9 billion. Analysts expect $19.67 billion.

Shares of Seattle-based Amazon.com Inc. fell $32.27, or 8 percent, to $370.74 in extended trading after the results came out. The stock had closed regular trading up $18.81, or nearly 5 percent, at $403.01.