NEW YORK — Shares of Best Buy Co. jumped Friday after the electronics chain showed signs of starting to reverse declining sales during the Christmas shopping season, a better-than-expected result.

Best Buy has been facing tough competition from discounters and online retailers, as people browse electronics in stores and then go home to buy them more cheaply online, a practice known as “showrooming.”

To combat this, it has instituted a cost-cutting program, invested in more employee training and put an online price-matching policy in place during November and December. The holiday quarter accounted for about a third of Best Buy’s revenue last year.

The chain said that revenue at stores open at least a year fell 1.4 percent for the nine weeks that ended Jan. 5. This figure is a key gauge of a retailer’s health because it excludes results from stores recently opened or closed.

The company’s U.S. performance was flat. While this was slightly below the 0.3 percent increase Best Buy reported a year ago, President and Chief Executive Officer Hubert Joly said in a statement that it was better than the past several quarters.

Best Buy hired Joly in August to help reverse its slide. Joly has made management changes, including hiring Chief Financial Officer Sharon McCollam in November, and embarked on a turnaround plan.

Morningstar analyst R.J. Hottovy said the results show that some of Best Buy’s initiatives helped increase sales.

But he said the company still faces bigger problems such as tough competition from sellers such as Amazon.com and more and more vendors selling products to customers directly.

“Sales are incrementally positive, but Best Buy still faces an uphill battle with regard to its turnaround,” he said.

Best Buy said that sales were strongest among cell phones, tablets, electronic readers and appliances, while sales of entertainment, televisions and computer-related items dropped.

Another encouraging sign was that online revenue rose 10 percent for the Christmas period, bolstered by better traffic, an increase that shows that the chain is managing to grab its share of online buyers as well.

“While it will be a journey with ups and downs, we are focused on becoming an increasingly effective multichannel retailer and engaging with the tens of millions of consumers who shop us online and in-store,” Joly said.

Revenue at stores open at least a year fell 6.4 percent internationally, stung by softness in China and Canada.

Total revenue for the holiday period fell slightly to $12.8 billion from $12.9 billion.

Best Buy lost CEO Brian Dunn in April, after an investigation showed he had an inappropriate relationship with a female employee.

That led to the departure of co-founder Richard Schulze, who knew about the relationship but didn’t report it properly, the investigation found.

Schulze stepped down, but he has been considering making a bid for the company. That bid had not materialized by the end of 2012, although Best Buy has given Schulze more time to look over its books and arrange financing for an offer.

Best Buy shares rose $2, or 16 percent, to close at $14.21. That’s still close to the low end of the stock’s 52-week trading range of $11.20 to $27.95. The stock hit its lowest point of the year Dec. 27.

Business, Pages 27 on 01/12/2013