Sears 49 of 59
Traditional retailers such as Sears are in danger as Amazon expands into new categories.

Business Insider/Hayley Peterson

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Amazon is on a roll.

The company just celebrated the biggest day in its history with the 30-hour Prime Day that ended on Tuesday. According to Amazon, the event grew 60% since last year, though the company didn’t provide specific sales figures.

However, when Amazon thrives, other companies often suffer. Even the mere rumor that Amazon is entering a new sector can cause potential rivals’ stocks to plummet. On Wednesday, Zillow’s stock dropped 3% following whispers that Amazon is building a real estate service of its own.

Here are seven companies that the ecommerce giant threatens:

Best Buy

Best Buy

Reuters/Shannon Stapleton

While Best Buy has been under siege by Amazon for years, the electronics retailer long had one advantage — the Geek Squad of employees ready to help customers with technical difficulties.

However, Recode reported that Amazon was preparing to launch a Geek Squad of its own, in the form of “army of in-house gadget experts to offer free Alexa consultations as well as product installations for a fee.” Shares of Best Buy dropped 7.5% Monday after the news broke.

Energizer

Energizer

Flickr / Danny Mckiernan

The future of batteries may be online — and that’s bad news for companies like Energizer.

While online sales of batteries only make up roughly 5% of total battery sales today, UBS said in a note…