The key to Amazon's success appears to be its wealthier and more loyal customer base.

Prime members are Amazon's "golden jewel," especially during the holiday shopping season, according to GBH Insights analyst Daniel Ives.

Ives said he expects the internet giant will capture as much as 50 percent of all online sales from November through the New Year. That compares with Amazon's share of 38 percent of the market in the same period last year.

Meantime, GBH Insights has predicted the average Prime customer is spending 20 to 25 percent more on Amazon.com around the holidays this year. Those customers' dollars are adding up, and quickly.

"The ring-fence that Amazon has built around its Prime customer base has significantly benefited the company in a fiercely competitive Cyber Monday pricing environment with much more competitive prices from Walmart in particular seen across inventory during the day," Ives wrote.