Updated

The Thanksgiving shopping tradition has gotten ahead of the holiday itself.

On Nov. 10, Wal-Mart Stores Inc. offered many holiday promotions online or within its mobile app. J.C. Penney Co. sent its Black Friday advertisements to users of its mobile app on Nov. 4, and started those sales on Wednesday, a day earlier this year than last year and one day ahead of Thanksgiving.

Across the industry, retailers released advertisements of their biggest deals three days sooner this year on average than last, according to Market Track LLC, which analyzed emails, social media and retail websites. And the volume of emails that retailers sent to customers, who opted to receive them, increased 15% from Oct. 1 through Nov. 19, compared with the same period a year earlier, Market Track found.

Shoppers spent $27.2 billion between Nov. 1 and Nov. 23, a 4.3% increase over a year ago during that same time frame, according to Adobe Systems Inc., which analyzed data from 21 billion visits to retail websites. Adobe predicted that online spending on Thanksgiving Day would reach $2 billion, up 16% from a year ago.

In the battle for shoppers and in an effort to hold off advances from online rivals such as Amazon.com Inc., traditional retailers have been moving discounts earlier in the month, linking their stores and websites more closely and finding ways to capitalize on the rise in mobile shopping.

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