Foot Locker Inc. shares are down 15.5% in Friday trading after the athletic shoe and apparel retailer said its first-quarter results were damaged by a delay in customer receipt of IRS tax refunds.

A law enacted in late 2015 states that the IRS can’t issue a tax refund on returns claiming an earned-income tax credit or additional-child tax credit until Feb. 15. It’s one of the primary reasons that some taxpayers delayed filing their returns this year.

That pushed back tax refunds, and some retailers and restaurants say purchases normally made during the quarter were postponed, at best, as a result.

“The slow start we experienced in February, which we believe was largely due to the delay in income-tax refunds, was unfortunately not fully offset by much stronger sales in March and April,” said Foot Locker FL, +0.05% Chief Executive Richard Johnson in a statement.

Foot Locker reported sales of $2 billion, up from $1.99 billion a year earlier. Same-store sales rose 0.5%. The FactSet consensus called for sales of $2.02 billion and a same-store-sales increase of 1.4%.

Earnings per share were $1.36, down from $1.39 a year earlier and below the $1.38 FactSet consensus.

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“The refund issue is often bandied about as an excuse for underperformance,” wrote Carter Harrison, an analyst at GlobalData Retail. “However, in Foot Locker’s case, we believe the point is a valid one, as many younger consumers use part of their windfalls to buy expensive sneakers, and many parents do the same for their kids.”

Johnson also said the company didn’t “have sufficient quantities of some of the hot running products that adult customers have been snapping up,” and the basketball business is soft, “which has been a relatively important component of kids sales in recent years.”

“Fortunately, as we move through the rest of the year, the kids exposure to signature basketball will lessen, and we expect lifestyle product quantities to improve,” he said, according to a FactSet transcript.

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But Harrison has ongoing concerns. “Although delayed refunds affected the first part of the trading period, it is more worrying that sales did not pick up towards the back end of the quarter,” he said. “Admittedly some of the fillip provided by refunds may well be pushed into the next period, but we believe current performance has also been tempered by a lower level of demand within the sporting-goods category.”

Still, Harrison believes demand across sporting goods will grow over the rest of the year, and Foot Locker, he said, can capitalize.

“The key to this success is the company’s drive to ensure it remains a key destination for sporting, and sneaker, enthusiasts,” he said.

Johnson emphasized the company’s place “at the center of a very vibrant sneaker culture” on the call.

The company might be on top of the sneaker trends, but the sales trends have been tougher. Johnson said Foot Locker is forecasting a same-store-sales increase in the low-single digits in the second quarter with relatively flat year-over-year earnings. The FactSet consensus calls for a same-store-sales increase of 4.4%, with earnings per share of $1.04, up from 94 cents last year.

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“While we remain optimistic that we can accelerate our momentum over the second half of 2017 to reach mid-single-digit comparable sales gains, we are developing a Plan B, so to speak, to pace the recent sales trends in case recent sales trends continue,” Johnson said.

Susquehanna Financial Group’s Sam Poser said he believes the March through May results will be a trend indicator. He’s optimistic about what the company has planned. “Foot Locker’s improving product offerings, excitement around Nike’s NKE, -0.27% NBA sponsorship, remodel lifts and overall high engagement with customers should continue to drive results and share gains, and we would buy on any weakness,” Susquehanna’s pre-earnings-call note said.

Susquehanna rates Foot Locker shares positive.