Traffic at Walmart Inc., Costco Wholesale Corp. and Target Corp. dropped for the first time in the weeks since the coronavirus pandemic ramped up in the U.S., according to Placer.ai.

Walmart WMT, -1.67% traffic was down 6.7% year-over-year for the third week of March. The previous week, traffic was up 18.4%.

At Costco COST, +0.05% , traffic fell 8.7% year-over-year for the third week of March. The second week of March, traffic jumped 34.7%.

And at Target TGT, -1.99% , traffic slumped 20.5% in the third week of March after climbing 19.2% year-over-year the previous week.

At each of the three retailers, traffic grew the last week of February and the first week of March.

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“There is a downside to stocking up for the long haul,” wrote Ethan Chernofsky, vice president of marketing for Placer.ai, in a post on the company’s blog.

Placer.ai is a retail intelligence company.

“Once you have all the things you need, there is little need for more visits,” Chernofsky wrote.

Placer.ai data shows that the slowdown was more pronounced in areas that have been hit harder by the coronavirus outbreak. For instance New York, which is most affected in the U.S., saw the sharpest decline, while in Arizona, where the impact has been far less, the decline wasn’t as steep.

“The positive here is that the data indicates that as the situation improves, and doesn’t worsen, consumer behavior tends to return to more normal patterns,” Chernofsky wrote.

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“Should this trend hold, it’s a very strong endorsement for those who believe that wider retail activity could quickly return to previous levels should the preventative measures being enacted serve their ultimate goal.”

Placer.ai says some of the decline could be attributed to the increased use of delivery services and curbside pickup as shoppers try to follow social distancing guidelines.

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Adobe ADBE, -3.36% data shows that U.S. grocery e-commerce sales grew 25% for the period between March 13 and March 15 compared with the period between March 1 and March 11.

And orders using buy-online-pickup-in-store capabilities soared 62% year-over-year between Feb. 24 and March 21. In addition to groceries, online orders for fitness equipment like dumbbells and computers also jumped during the month of March.

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Target has seen a shift in spending such that consumers are buying small appliances to prepare all of the groceries that they’ve put in the pantry.

Or, Placer.ai proposes, it could just be a lull before shoppers head out to stock up again.

Target stock has rallied 19% over the past year. Walmart shares have grown 22.1%. And Costco stock has gained 20.2%.

The Dow Jones Industrial Average DJIA, -1.92% has slumped 18.3% for the period.

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