SEATTLE — Even as adjusted sales from brick and mortar Whole Foods Market stores held about steady in the fourth quarter ended Dec. 31, 2018, overall Whole Foods sales enjoyed solid growth thanks to the company’s Prime Now app.

In a Jan. 31 conference call with investment analysts, Brian T. Olsavksy, Amazon’s senior vice-president and chief financial officer sought to offer a complete picture of Whole Foods sales trends. Whole Foods is owned by Amazon.com, Inc.

Mr. Olsavsky said Amazon physical store sales slipped 3% in the third quarter, principally because of Whole Foods (the figure also includes other stores — Amazon Bookstores, Amazon Go and Amazon Four Star). Partly accounting for the decline was a realignment in 2017 linking up the fiscal calendars of Amazon and Whole Foods, adding about five days to revenue in the fourth quarter of 2017. Amazon’s acquisition of Whole Foods closed in August 2017.

What isn’t counted in store sales are orders for delivery or pickup at Whole Foods using the Prime Now app, Mr. Olsavsky said during the call.

“If you adjust for those, what’s the Whole Foods growth year-over-year on an apples-to-apples basis was approximately 6%,” he said. “Because of some of those, again, mostly the year-over-year counting or days true-up issue, it’s showing up as negative 3% in physical stores.”

Announcing the company’s financial results, Amazon listed growth of its grocery delivery and pickup geographic footprint among highlights for the year.

“Amazon expanded free grocery delivery and pickup from Whole Foods Market through Prime Now, allowing customers to place their order via the Prime Now app and choose delivery in as fast as an hour or pickup in as little as 30 minutes,” the company said. “Grocery delivery is available in more than 60 U.S. metros and pickup service is available in more than 20 U.S. metros with plans for continued expansion.”

In the year ended Dec. 31, Amazon net income was $10,073 million, equal to $20.68 per share on the common stock, up 232% from $3,033 million, or $6.15 per share. Sales were $141,915 million, up 20%.

In the fourth quarter, Amazon net income was $3,027 million, equal to $6.18 per share, up 63% from $1,856 million, or $3.85 per share.

In trading on Nasdaq Feb. 1, the day after the financial results were issued, Amazon shares closed at $1,626.23 per share, down $92.50, or 5.4%.