Amazon (AMZN - Get Report) Prime Day looked set to become the biggest in the company's history but investors seemingly shrugged it off.

Amazon shares were only 0.37% up in Wednesday premarket trading, and were expected to open at $997.79 after closing on Tuesday at $994.13.

Amazon on Tuesday said that its 30-hour Prime Day sale was on track to be the biggest shopping event in history by sales, and that customers ordered more than three times as many Echo-family speakers as on Prime Day 2016, Reuters reported.

The company has not yet released sales figures for the day, but said third-party sellers sold more than 50% more items by noon Eastern time than in the same time frame last year.

The Echo was largely seen as the best deal of the day, with Amazon offering the Echo at half price in the U.S., or $89.99, compared with 28% off on Prime Day in 2016.

Amazon stood to ring up more than $2 billion in sales worldwide during the 30-hour sale known as Prime Day, Internet Retailer predicted. The gain would mark about a 21% increase from a year ago. U.S. sales alone are pegged at $1.56 billion, up 20% from last year, TheStreet reported.

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