Where is Amazon Fire TV?

Amazon Fire TV
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Mystery solved, well, sort of.

Amazon Fire TVs are currently unavailable due to "overwhelming customer demand," an Amazon spokeswoman said, after the little black box set social media abuzz when it mysteriously disappeared from stock on a few days ago.

For some users, the page says Fire TV could be available again by Aug. 23, which CNBC was unable to confirm. Amazon did not comment on a reason for the backlog.

The dearth of Amazon's $99 TV streaming device led some to speculate whether it was being upgraded to be 4K compatible, CNBC's Carl Quintanilla said on "Squawk Alley" Tuesday. A potential revamp by the e-commerce giant would allow customers streaming video on the web to get the highest image resolution on the market—four times that of an ordinary TV.

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Fire TV continues to add new features. Last month, Amazon said the TV would soon begin carrying premium channel HBO Now, on top of the 700 channels, apps and games and 2,000 titles added since February.

Fire TV and with lower-end model Fire TV Stick, which is still available, are among the top-selling over-the-top (OTT) streaming devices in a crowded field of players, including Roku, Google Chromecast, Apple TV, and even Microsoft's Xbox. Competitor Apple TV is likely to unveil a new model in September.

The devices feed into a larger trend of "cord-cutting." The 47 percent of Americans tuning in to digital TV expected to grow to 53.8 percent by 2019, according to research firm eMarketer. A separate report by industry researcher Digital TV Research expects almost 30 percent of TVs to be connected to the Internet by 2020.

Amazon did not break out total sales of Fire TV, which has 31,378 customer reviews, in their latest earnings report. But in his annual letter to shareholders, CEO Jeff Bezos commented on the TV's role in the business.

"Amazon designed and manufactured devices—from Kindle to Fire TV to Echo—also pump energy into Prime services such as Prime Instant Video and Prime Music, and generally drive higher engagement with every element of the Amazon ecosystem. And there's more to come—our device team has a strong and exciting roadmap ahead," he stated.

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