Wendy'sWendy’s may gain momentum in the second half of 2013 at the expense of McDonald’s, according to at least one securities analyst.

The Wendy’s Co. expressed greater optimism for sales and margin growth for the remainder of the year than McDonald’s Corp., even though both companies reported only slight increases in same-store sales for the second quarter.

Oak Brook, Ill.-based McDonald’s reported a 1-percent increase in U.S. same-store sales for the second quarter, while those for Dublin, Ohio-based Wendy’s rose 0.4 percent at company-owned restaurants and 0.3 percent at franchised locations. Yet executives’ sentiments during the brands’ respective earnings calls diverged.

McDonald’s forecasted flat same-store sales for July, and executives said they expect a “challenged” environment for the rest of the year. Meanwhile, Wendy’s said its full-year same-store sales would range from 2 percent to 3 percent after climbing just 0.7 percent in the first half, suggesting robust sales next quarter.

Mark Kalinowski, restaurant industry analyst for Janney Capital Markets, predicted that Wendy’s could drive third-quarter same-store sales as high as 5 percent based on the performance of its Pretzel Bacon Cheeseburger, which is likely living up to expectations, he wrote in a research note. In a separate note covering McDonald’s second-quarter earnings, Kalinowski wrote that one reason McDonald’s predicts flat sales for July is because a resurgent Wendy’s began advertising its new premium sandwich nationally.

“This pressure on McDonald’s could last over the third quarter as a whole, and perhaps beyond, if Wendy’s adds its Pretzel Bacon Cheeseburger as a permanent menu item, which looks increasingly likely,” he wrote.

While not quite as bullish as Kalinowski, another analyst, Anton Brenner of Roth Capital Partners, wrote that Wendy’s would likely hit its high-end target of 0.5-percent growth in profit margin for 2013, provided that the company’s remodeling program and planned refranchising of 425 units overcome headwinds, such as a “continuing sluggish industry sales environment and Wendy’s lack of a breakfast program.”