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Amazon is major player in Cyber Monday sales, which are expected to top last year's numbers.

Cyber Monday sales were off to a big start -- hitting $531 million in online sales by 10 a.m. ET on Monday, according to data provided by Adobe Analytics. 

The day is predicted to hit as much as $7.8 billion in sales, growing nearly 18% over last year, according to Abobe. Between 10 p.m. and 1 a.m. ET is predicted to bring in $1.6 billion alone, according to Abode.

If the numbers turn out correct, the day is expected to be the largest online shopping day yet.

Nearly all major retailers are participating in the day -- including Amazon.com Inc.  (AMZN) , Target Corp.  (TGT) , eBay Corp.  (EBAY) , Kohl's Corp.  (KSS)  and Walmart Inc. (WMT) , as well as most smaller and specialty retailers, such as Etsy Inc.  (ETSY) . It will mark retailers' last chance to lure shoppers over the Thanksgiving weekend discount bonanza.

Most retailers saw shares trading up in the morning, with Etsy rising 2.5%, Amazon over 3.3%, Target 1.6%, Ebay about 1.7% and Kohl's about 0.8%.

While not expected to make nearly the projected sales of Black Friday, Cyber Monday is slated to bring in a number of late-shoppers, according to the National Retail Federation. The group expects as many as 76 million people to buy online, capping what is expected to be a big weekend for shopping that saw sales start on Thanksgiving Day, surge over Black Friday, and make steady traffic on Small Business Saturday. 

"Despite some of the best deals coming earlier in the holiday season, the Cyber Monday brand has great staying power," said Taylor Schreiner, director of Adobe Digital Insights in a statement. "Many shoppers have waited on certain purchases, with three hours tonight expected to bring in as much revenue as an average full day. While certain discounts have remained since Black Friday, out-of-stock rates are starting to peak up and shoppers looking for the hottest products should not wait much longer."

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