A stunning Under Armour financial streak just ended. The Baltimore-based sports apparel company had delivered 26 straight quarters of 20% or higher sales growth—until now.

Under Armour missed big on its 2016 fourth quarter earnings, reporting revenue of $1.31 billion on expectations of $1.41 billion, and earnings of 23 cents per share on expectations of 25 cents.

The problem was North America, where sales grew 5.9% in the quarter, a far cry from its average quarterly growth of nearly 25% for the past three years. Now longtime CFO Chip Molloy is resigning, the company announced.

Even worse: Under Armour now says it expects operating income to fall by $100 million for 2017. “So the natural question,” CEO Kevin Plank said on the earnings call, “is why? Why is operating income going backwards?”

There are a few answers. For starters, the bankruptcies last year of major US sports retail chains, like Sports Authority, Golfsmith, Eastern Mountain Sports, Bob’s Stores and Sports Chalet, crushed many sports brands. As Plank said, that’s “certainly not new news,” but it “disrupted the North American retail landscape.” Plank was among a number of CEOs to have breakfast with President Donald Trump on his first weekday in office.

Because 85% of Under Armour’s global revenue comes from North America, it is particularly affected (more so than Nike or Germany-based Adidas) by shifts in the US retail scene. “But we have momentum toward greater global balance,” Plank assured investors.

In addition, competition from other brands is tougher than ever, especially from Adidas, which had an excellent 2016 and managed to claw back market share in US footwear. Back in 2014, Under Armour took the No. 2 spot from Adidas in US apparel; last year, Adidas took it back. Adidas is flying just as Under Armour is flailing.

But most compelling of all, Plank said Under Armour has learned that it must stay premium to win at retail stores—that is, avoid being sold in discount environments. “The role both we and our retailers expect us to play is as a premium, full-price brand,” Plank said. “This means amplifying our agenda for newness and innovation at every price point, as our partners expect UA to be the premium brand of choice at their stores.”

The sneaker business is actually a mostly full-price business. At stores like Dick’s Sporting Goods and Foot Locker, sneakers are mostly sold at the brand’s suggested retail price. But every brand also sells to discount stores like Marshalls, and at a discount at their own outlet stores.

To keep a premium image like Plank wants, says NPD Group retail analyst Matt Powell, “You don’t put too much inventory in the marketplace. It’s not a matter of telling retailers you can’t price-promote [sell at a discount], it’s controlling your inventory at a point where they don’t need to promote.”