In the battle of department stores, Kohl's Corp. has gained an edge on its more upscale rival Macy's Inc.

The stock has outpaced Macy's this year, bolstered by stronger holiday season sales. Investors are betting that the chain will maintain that advantage, with the shares trading at their highest premium to Macy's in more than four years.

Kohl's, the third-largest U.S. department-store chain, has succeeded by promoting outside brands such as Levi's and Nike — departing from a long-held retail-industry strategy of focusing more on in-house and exclusive products you can't get elsewhere. That emphasis on familiar, national names has been reeling in shoppers.

"Kohl's had a big hiccup, and they had to figure their way out of it," said Poonam Goyal, a retail analyst at Bloomberg Intelligence. The retailer's increased focus on national brands has boosted traffic, and the loyalty program is "working really well for them."

Macy's, by contrast, is struggling to find new avenues of growth and meet investors' expectations that it raised over the past five years, when its performance was the envy of its department-store rivals.

The company can no longer rely on the tried-and-true approach of using exclusive products and private labels that helped fend off online merchants and attract shoppers during the choppy economic recovery.

While Kohl's still gets about half of its revenue from in-house brands like Croft & Barrow and Sonoma — along with exclusive versions of national brands such as Food Network and Simply Vera Vera Wang — the company last year instituted a plan to re-emphasize national brands and add goods by Izod, Fitbit and Nespresso.

The shift is paying off.

Comparable-store sales of national labels outpaced only-at-Kohl's merchandise in the year ended Jan. 31, helped by a 24 percent gain in sales of Nike Inc. products in the fourth quarter.

Total holiday-quarter same-store sales rose 3.7 percent, the biggest gain since 2010 and almost twice the 2 percent increase at Macy's.

Kohl's stock has gained 26 percent this year, closing Monday at $76.62. Macy's closed at $64.44, down 2 percent for 2015.