Shoppers at Third Street Promenade

Shoppers brave Santa Monica's Third Street Promenade on the last Saturday before Christmas. (Liz O. Baylen / Los Angeles Times / December 21, 2013)

In store after store, signs trumpeted 50%-off deals, buy-one-get-one-free promotions and free gift cards with purchases. Shoppers scuttled past holiday decorations with bags hanging from their hands to their elbows. A little girl at Old Navy begged her mother to ask Santa to buy her three glittery plastic bracelets in different colors.

Black Friday? Try Super Saturday.

The start of the last weekend before Christmas is indisputably one of the busiest shopping days of the year. ShopperTrak ranks it second in sales and foot traffic, behind only the Friday after Thanksgiving.

It's an especially nerve-racking event for retailers because it signals the final push before Christmas — and their last chance to prop up their earnings and empty their shelves before the end of the year.

The holiday season accounts for as much as 40% of some stores' annual revenue. The National Retail Federation anticipates that sales will rise 3.9% compared with last year's holiday season, to $602 billion.

Stores are bracing for the annual influx of returns and shopper ennui that arrives Dec. 26 and tends to last well into January. Retailers then slash prices on remaining inventory to make room for the incoming spring collections.

Loath to essentially give away leftover stock at the end of the year, retailers are hustling to pack in shoppers now.

Toys R Us said it will stay open for 87 straight hours before Christmas; Kohl's will keep the lights on for more than 100 hours. Barnes & Noble is plying shoppers with free gift wrapping.

"I call it Procrastinator Saturday," Moody's analyst Scott Tuhy said. "People finally realize there's only two more shopping days to go. It's a very impactful weekend."

Military man Usi Wells, 35, of Hollywood said Saturday that he had as much as 30% of his holiday shopping left to do. So he trawled Third Street Promenade in Santa Monica for hours before taking a break on a bench, surrounded by Adidas and Banana Republic bags.

The deep promotions being offered were a good incentive to shop right away instead of waiting even longer, he said. Although he estimated that he'd spent $1,550 on apparel, he guessed he saved $400 by not buying at full price.

"This season's come along very quickly — it seems like in a blink of an eye," Wells said. "Most years, it's a lot slower and you have a lot of time to think about shopping."

Retailers have struggled to make the most of the shortest Thanksgiving-to-Christmas period in more than a decade.

Some resorted to deep discounting. Online clothing store ModCloth tried to compel people to do some "me-gifting" with a 50%-off "Treat Yourself Sale."

"Given the shorter shopping period and the guarded consumer who's not willing to spend, especially on more discretionary items, retailers are pulling out all the stops to get people to visit stores or websites," S&P analyst Ana Lai said.

If recent spending is any indication, a large chunk of Super Saturday sales will have occurred online.

The week that began Dec. 9 was the first ever to have five individual weekdays surpass $1 billion in e-commerce revenue, data firm ComScore said Wednesday. U.S. consumers have spent $19.2 billion online since Thanksgiving — up 21% compared with the same period last year.

The surprising detail, however, is the huge surge in Internet spending on the weekends, according to ComScore. Last weekend, online shoppers shelled out $1.6 million — a 41% swell compared with a year earlier.

ComScore Chairman Gian Fulgoni speculated that consumers are adjusting to the shorter season by supplementing their shopping with weekend visits to websites. Plus, he said, "perhaps some consumers are opting to shop from home and avoid the long store lines."

He also suggested that many Americans might be investigating products in stores and then using their mobile devices to search for better deals online, a phenomenon known as showrooming.

Inglewood attorney Jovan Blacknell, 34, was initially wary of facing the crowds at the Grove shopping center. By Saturday, his 5-year-old son's and 1-year-old daughter's gifts were in order — a hodgepodge of Spider-Man gear, drawing tools and kitchen play sets.

But his wife's present was unaccounted for. So Blacknell mustered up enough holiday cheer to pick up a purse from Nordstrom that was marked 10% off.

"I'd prefer not to go to stores when they're so busy," he said.

tiffany.hsu@latimes.com

he said.

tiffany.hsu@latimes.com