Under Armour has overtaken Adidas this year in combined apparel and footwear sales to become the second biggest sports brand in the United States.

Baltimore-based Under Armour had U.S. apparel and footwear sales of $1.2 billion through the end of August, edging ahead of Adidas with $1.1 billion total U.S. sales, according to a Sterne Agee report citing sales figures from SportScanInfo. Under Armour sales have jumped 20 percent this year, while Adidas combined sales have plummeted 23 percent.

Market leader Nike, with 46 percent of the athletic footwear market and a third of the sports apparel sales, far outpaces its competitors with a combined $8.9 billion sales so far this year.

Under Armour has been stealing market share in apparel sales for months from its older German rival and from Nike, according to Sterne Agee.

Under Armour's sports apparel sales, which account for 14 percent of the U.S. market, expanded to more than twice those of Adidas. Adidas, with a six percent share of the apparel market, continues to rank third as a footwear brand behind Nike and Jordan, with more than double Under Armour's fledgling, but growing, footwear sales.

"Under Armour and Nike are constantly dissatisfied, and Adidas hasn't had the same sense of urgency," said Sam Poser, a managing director and research analyst with Sterne Agee. "Adidas sometimes sits back on their laurels too much and the other folks pass them by. What we're seeing now is an example of that."

The year-to-date report reflects a trend of Under Armour's apparel sales growing while Adidas' decline, eating away at Adidas market share. In February for instance, Under Armour's apparel sales were nearly triple those of Adidas. The German company said in a quarterly earnings report last month that its sales grew in all regions in the first half of the year except in North America, where it had double-digit declines in the United States.

Under Armour CEO and founder Kevin Plank has repeatedly stated the relatively young company's goal of becoming the world's biggest sports brand by targeting the women's sports apparel and footwear markets, expanding its base of Under Armour retail outlets and spreading its brand around the globe, where sales now account for less than 10 percent of revenue. The company anticipates nearly $3 billion in sales this year.

Last week, just days after losing out on a bid to sign NBA star Kevin Durant to a basketball-shoe deal, Under Armour announced the signing of Brazilian supermodel Gisele Bundchen to its lineup of representatives including ballerina Misty Copeland and skier Lindsey Vonn for its biggest-ever, $15 million, ad campaign aimed at women.

Since late last year, the company has become the exclusive supplier to teams at Notre Dame and the U.S. Naval Academy, expanded into Brazil and opened branded stores in China and New York City.

For much of the year, Under Armour has been battling it out with Nike.

Poser said in a May research report that the two brands' apparel sales were continuing to dominate, with Nike capturing sales in mid-tier department stores and Under Armour seeing healthy gains in share through athletic specialty and sporting goods retailers and taking share from the larger Nike from those stores. That month alone, sales jumped 18 percent for Nike and 22 percent for Under Armour while sales declined sharply for Adidas, Russell and Champion.

"Nike and Under Armour … are annihilating the competition," Poser wrote. "It appears as if the women's apparel will be the battleground going forward."

Lorraine.mirabella@baltsun.com