Wendy’s Co. surpassed Burger King Holdings Inc. in sales last year, making it the second-largest U.S. hamburger chain, according to Chicago-based researcher Technomic Inc.

Sales at Dublin, Ohio-based Wendy’s U.S. locations were $8.5 billion last year, while Miami-based Burger King’s sales were $8.4 billion, according to Technomic. McDonald’s Corp., based in Oak Brook, Illinois, is the largest chain with $34.2 billion in sales at all of its U.S. stores in 2011.

Wendy’s Chief Executive Officer Emil Brolick has sought to boost sales recently by promoting more expensive, premium burgers and has started remodeling its U.S. stores to lure consumers. Sales at the 500 largest U.S. dining chains advanced 3.4 percent to about $242 billion last year, compared with an increase of 1.8 percent in 2010, the researcher said.

Technomic will release its chain restaurant report on April 13.

Closely held Five Guys Burgers and Fries, with sales of $951 million last year, was listed as the fastest-growing chain with sales greater than $200 million. Five Guys is based in Lorton, Virginia.

Wendy’s fell 0.2 percent to $5.03, and McDonald’s rose 0.1 percent to $97.73 at the close in New York.

Burger King has attempted to gain market share and turn around declining same-restaurant sales in North America by revamping its menu with new French fries and soft-serve ice cream. 3G Capital Inc. bought Burger King in 2010 for about $3.93 billion. (Bloomberg)