The traditional Black Friday kickoff to the holiday shopping season may be four weeks away, but retailers are trying to prod consumers into an early start.

Walmart said this week that, starting Sunday, shoppers can expect to see extended “rollback” price cuts that last as long as 90 days , instead of the typical “this weekend only” holiday promotions.

Target also jumped on board, saying it plans to boost the number of stores participating in its curbside pick-up strategy, which allows consumers to buy online and pull up to a store for their purchases.

And electronics giant Best Buy plans a pre-holiday promotion Nov. 7 that will include Black Friday-like discounts, a chance to win Best Buy gift cards and free tech gifts for the first 100 in the door at area locations.

Each also is putting more emphasis on mobile sales, including making more space in stores for online pick-ups and offering new app functions, such as the ability to see what’s on a Walmart customer’s gift wish list.

The jockeying to pull in early-bird shoppers is not unusual, but signals the high stakes for the retail industry, which makes an out-sized portion of its revenue during the holidays.

Holiday sales are expected to reach around $630 billion this year, but will rise more slowly than last year because of sluggish wage growth — up 3.5 percent for 2015 vs. 4.1 percent in 2014, according to industry experts and the National Retail Federation.

“Holiday retail sales are looking good but not as strong as last year in growth terms,” said analyst Chris Christopher, of IHS Global Insight.

A lot could depend on when stores open. The biggest retailers — including Macy’s, Walmart, Target and Best Buy — have shifted to opening on Thanksgiving Day to boost sales. But the move has been controversial, with some complaining the so-called “Gray Thursday” is disruptive to families and trivializes the holiday.

None of those brands have announced their Thanksgiving plans for this year.

Outdoor outfitter REI is taking a different tack, announcing it will be closed not only on Thanksgiving but also on Black Friday. There are five REI stores in metro Atlanta.

“For 76 years, our co-op has been dedicated to one thing and one thing only: a life outdoors,” said CEO Jerry Stritzke. “We believe that being outside makes our lives better. And Black Friday is the perfect time to remind ourselves of this essential truth.”