BENTONVILLE, ARK. — Strong price positioning, fresh quality and improved in-stocks are driving solid gains within the grocery business at Walmart, Inc.

“Grocery sales were up 6% (in the second quarter), including the benefit from modest ticket inflation and increased low double digits on a two-year stack basis,” M. Brett Biggs, executive vice president and chief financial officer, said during an Aug. 17 conference call with analysts. “That results in $2.4 billion of growth in food sales year-over-year and about $5.5 billion of growth on a two-year stack.”

Overall, net income at Walmart in the second quarter ended July 31 totaled $4.28 billion, equal to $1.53 per share on the common stock, down 34% from $6.48 billion, or $2.29 per share, in the same period a year ago. Operating income, meanwhile, was $7.35 billion, up 21% from $6.06 billion in the same period a year ago.

Net revenues improved 2.4% to $141.05 billion from $137.74 billion.

“Our strong second quarter and the solid start to the third quarter position us to deliver a great year of financial results while making steady progress against our strategic priorities,” Mr. Biggs said. “Our results continue to demonstrate the power of the omni strategy, providing customers with new products, services and tools. No matter how customers want to shop, we're here for them.

“In some periods, in-store shopping will lead the way, and in some, e-commerce will lead the way. While we're always striving for more in each part of the flywheel, I'm pleased with the overall growth of the business.”

John R. Furner, chief executive officer and president of Walmart US, said a key for the retailer has been unit share in categories like food growing faster than dollar share, something he said allows Walmart to “position ourselves well in terms of retail value for the customer and play a role in keeping inflation down for the country.”

Mr. Furner added that Walmart has experienced strong performance within its US supply chains.

“The teams have just done a number of things to ensure that flow is strong, and that would include everything from offshore to onshore properties like our distribution network,” he said. “And in particular, our food distribution team has done an amazing job keeping products moving.”