Walmart has today posted a bigger than expected increase in quarterly same-store sales and beat expectations for profit amid a surge in its online business with higher spending on electronics, sporting goods and groceries. 

Sales at US stores open at least a year rose 6.4%, excluding fuel, in the third quarter ended October 31.

Analysts had estimated an increase of 4.16%, according to IBES data from Refinitiv. 

Walmart's US eCommerce sales grew 79% with strong results across all channels and helped boost same-store sales and profit margins. 

The surge in demand for essentials at Walmart seen at the peak of the coronavirus lockdowns has carried into the second half of the year.

US consumers are relying on its same-day delivery options and store pick-up services to buy everything from groceries to sneakers. 

"We think these new customer behaviors will largely persist and we're well positioned to serve customers with the value and experience they're looking for," chief executive Doug McMillon said in a statement. 

The Covid-19 pandemic has also forced retailers to drastically rethink how they do business during the key holiday season.

Many big US retailers including Walmart, Kohl's, Target and Best Buy moved their promotions to as early as October. 

An early start to the holiday season has helped Arkansas-based Walmart's "customers the opportunity to come to stores when they aren't as crowded as they typically would be on a one-day Black Friday type of event," the company's chief financial officer Brett Biggs said today. 

Despite a slow start to the back-to-school shopping season, which typically begins in July, Walmart said it benefited later in the quarter. 

Walmart said it incurred about $600m in additional Covid-19 expenses that included higher wages for warehouse workers and bonuses for store employees, as well as spending more on cleaning facilities. The retailer had recorded about $1.5 billion in such expenses in the prior quarter. 

Executives said on a call with investors they expected Covid-related costs to continue for "some time, along with some general global uncertainties." 

Shares of the company have risen 28% this year. 

Walmart's operating income jumped 22.5% to $5.79 billion in the third quarter, while Walmart reported adjusted earnings per share of $1.34 that topped expectations for $1.18. 

Total revenue rose 5.2% to $134.71 billion, beating estimates for $132.23 billion. 

Among increased investments in e-commerce, the retailer in September launched its subscription service Walmart Plus, touted as a rival to Amazon.com's Prime subscription, which includes perks like free shipping and streaming services. 

Walmart Plus membership costs $98 per year and offers services such as unlimited free delivery, fuel discounts and no checkout lines.