Amazon holds Prime Big Deal Days

(CBS, KYMA) - With the holiday shopping season just around the corner, Amazon kicked off its second Prime Day sales event of the year Tuesday.

Amazon says Prime Big Deal Days includes millions of items, many with double-digit discounts.

Observers say the online retail giant's own private labels are playing a big part.

"You have things ranging from 70% off. Especially for Amazon products, they are really taking advantage of their private labels to give consumers big discounts. You see things like the Amazon Echo echo buds or the Amazon fire tablet with up to 50 to 70% off listed price. And again that's because it is their a private label, which gives that extra flexibility."

Sabrina Escobar, Barron's

According to Adobe, overall U.S. online sales are forecast to surpass $253 billion this holiday season. That's up more than 5% from last year.

Meanwhile, Amazon rivals Walmart and Target both plan sales promotions in the days ahead.

Prime Big Deal Days ends Wednesday.