NEW YORK (CNN/Money) - Amazon.com Inc. said Thursday it posted a third-quarter profit that fell just shy of Wall Street estimates.

The Web's largest retailer reported a third-quarter net income, excluding one-time items, of $73 million, or 17 cents per share, compared with $48 million, or 11 cents per share in the year-earlier period.

Sales increased 29 percent to $1.46 billion. The company's international division reported sales up 52 percent from a year ago.

Analysts had forecast a profit of 18 cents a share for the quarter on sales of $1.4 billion.

Shares of Amazon (Research) fell 8 percent in after-hours trading on INET, after gaining 3 percent to $39.47 in regular trading on Nasdaq.

Including stock compensation expenses, restructuring and other charges, Amazon posted a net profit of $54 million, or 13 cents a share, for the quarter, compared with a profit of $16 million, or 4 cents a share, a year earlier.

Amazon said it expects sales of $2.29 billion to $2.54 billion for the fourth quarter, which would be up from 18 percent to 31 percent from a year earlier, and from $6.6 billion to $6.9 billion, or up from 27 percent to 32 percent, for all of 2004.

That compares with analysts' average forecasts of $2.4 billion for the quarter and $6.8 billion for the full year, according to Thomson/First Call

Though Amazon did not give earnings-per-share guidance, it said it expects operating income of $137 million to $197 million for the fourth quarter and operating income of $415 million to $475 million for 2004.

Analysts forecast a profit of 41 cents a share in the fourth quarter and 99 cents a share for all of 2004.

However, Amazon said sales for full-year 2005 are expected to be come in at $7.40 billion to $8.15 billion. That's below analysts' consensus estimate of $8.2 billion, according to First Call.

"The guidance for 2005 is well below our forecast, and it implies a growth of only 14 percent," said Safa Rashtchy, analyst with Piper Jaffray. "Our forecast was for growth of about 20 percent."

"This could be a case of Amazon just being overly conservative, or business is slowing down and the company is feeling pressure from competitors," he added.

During a conference call with analysts, Amazon's chief financial officer Tom Szkutak said the company was "cautiously optimistic" about the future, adding that "it was not possible to accurately predict demand going forward."

Additionally, Amazon said operating expenses were higher during the quarter as the retailer increased investment in technology, content and Web services

Regarding the upcoming holiday shopping season, Szkutak said Amazon customers should look forward to more product selection and lower prices on holiday merchandise "than in years past."