Inc. fell short of Wall Street’s expectations for its third quarter, posting net sales of $20.58 billion and a net loss of $437 million, or 95 cents per share. Analysts were on average expecting a loss of 74 cents per share on revenue of $20.84 billion.

It was the largest quarterly loss in the company’s history, and it sparked investor concerns that the highly diversified e-commerce giant is overstretched as it moves into niche markets like same-day grocery delivery.

To boot, Amazon released fourth-quarter sales and earnings projections that also missed analysts’ predictions. The online retailer’s shares were off more than 11 percent in after-hours trading Thursday.

Amazon’s revenues were up 20 percent for the period, but it wasn’t enough to offset significant spending increases that CEO Jeff Bezos hopes will pay off in the future. Analysts worry that, by entering new markets like mobile hardware and data hosting, the company is stretching itself too thin.

“This is a hard one to swallow,” Lou Basenese, founder of Disruptive Tech Research, told CNBC. “This is going to make it tough to justify that we’re investing in the future.” Needham & Co.'s Kerry Rice said the outlook for Amazon is “a little ho hum as we get into Christmas,” according to Bloomberg.

In recent quarters, Amazon launched the Kindle Voyage, Fire phone (sales of which have been weak), its Fire TV service, and in September acquired streaming-games specialist Twitch for $970 million. It has also announced plans to open a brick-and-mortar store on some of the world’s most expensive commercial real estate -- across the street from Manhattan’s Empire State Building.

Bezos is undaunted as the company heads into the final quarter. “As we get ready for this upcoming holiday season, we are focused on making the customer experience easier and more stress-free than ever,” said Bezos, in a statement.