On Wednesday, Walmart, the largest retailer in the world, surprised investors and rattled markets when it cut its sales forecast for the remainder of 2015, and reported an earnings miss.

While the Bentonville, Arkansas chain painted a rosy picture, talking in its earnings report about its outlays of cash to boost employee salaries and to increase its e-commerce presence, financial experts like Andrew Duguay, senior economist at data analytics company Prevedere, were circumspect. He said Walmart must increasignly operate in a world where it faces online titans such as Amazon, as well as a host of retail startups that are mounting a competitive battle. 

Yet for many it seemed one more indication that the economy is growing too slowly, and, perhaps more ominously, that Walmart's miss could wallop upcoming holiday sales as well.

"It certainly gives me a bleak outlook for the holiday season, especially given the fact that there's a high correlation between seasonality and our sales," says William Bauer, managing director of Royce, a family-owned business started by Bauer's grandfather in the 1970s. Royce, a manufacturer of fine leather goods, is an Inc. 5000 company and a supplier to Walmart's e-commerce channel, as well as its Sam's Club subsidiary. "It is perhaps a sign of poor consumer confidence during the most important part of the year."

Royce, which is based in Secaucus, New Jersey, has 26 employees and expects sales to increase 15 percent to $6.5 million in 2015. A soft holiday season could take the wind out of that forecast, Bauer says.

While the National Retail Federation predicts a year over year sales uptick for the holiday season of 3.7 percent, that's down from the 4.1 percent increase of 2014. Sales for the season will increase to $630.5 billion, says the retail association. 

The holiday months are the most important selling time for many retailers, and it's expected to total 19 percent of annual sales for the retail industry, the NRF says.

Yet other indicators, like the Department of Commerce's monthly sales report, shows retailing weakness. For the nine months ending September, general merchandise sales grew a scant 0.7 percent to $478 billion, compared to the same time period in 2014. And for September, general merchandise sales fell 10 percent to $51 billion, on an unadjusted basis. After adjusting for seasonal differences, sales were essentially flat, falling to $57 billion.

Walmart will spend close to $1 billion this year on upping the ante for its workers, including increasing training and education, plus boosting its base wage to $9 an hour. Yet, with $500 billion in annual sales, Walmart is facing the cold reality that, as an older company, it will be harder to sustain a high growth rate. That's the opinion of experts such as Mitchell D. Weiss, an adjunct finance professor at the ?University of Hartford.

The really rapid growth is increasingly the domain of online retail plays like Amazon and Jet.com, which don't have the same labor costs, says Duguay. Amazon overtook Walmart in terms of market value for the first time in July after announcing a profit of $92 million in the second quarter, which it rarely does. And though startups like Jet.com are also not profitable, the online discounter recently junked its membership model for the more than 765,000 people who have signed up for its service, saying strong sales would make up for the lost revenue of the memberships.

Jet.com maintains a stated goal of getting to $20 billion of gross merchant volume by 2020. A company spokesman recently told Inc., the company doubled its sales volume to $20 million in September, compared to August, and expected that growth trajectory to continue.

Similarly, online deals and merchandise discounter Saveful of San Francisco, said it expected sales volume to increase in 2015 by more than 50 percent to more than $1 million, while it also doubled its customer base to 300,000 this year. The company has six employees.

All the same, Saveful's founder and chief executive Nick Porfilio is worried that the Walmart news will also dampen his own holiday season, potentially shaving 2 percent from total yearly sales. He says that he will try to make up for the deficit by cutting prices and increasing volume.

"Walmart's sales level is a bellwether for retail sales in general so we are certainly concerned about a weaker holiday season," Porfilio says.