(Reuters) -- Amazon.com Inc shares slumped after the largest Internet retailer said it may lose money in the first quarter, a sign the company is continuing to spend heavily on expansion and new ventures.

Amazon said fourth-quarter net income was $177 million, or 38 cents per share, down from $416 million, or 91 cents per share, a year earlier.

Revenue came in at $17.43 billion, up 35 percent from the fourth-quarter of 2010.

Amazon forecast first-quarter operating results ranging from a loss of $200 million to a profit of $100 million. That includes about $200 million for stock-based compensation and other expenses.

Amazon was expected to make $426.5 million in the first quarter of 2012, according to a survey of six analysts by Thomson Reuters. These estimates include stock-based compensation and other expenses.

Amazon shares dropped more than 9 percent in after-hours trading following the results.

(Reporting By Alistair Barr; Editing by Richard Chang)