Burger King regained its position as the second-largest U.S. burger chain after six years, overtaking Wendy's as its U.S. business accelerated in the second quarter. The shift was driven by an 8.5% rise in same-store sales, a closely watched retail measure that tracks performance at locations open at least a year. Wendy's moved the other way, reporting a 7% decline in the same metric and extending its streak of quarterly same-store sales contractions to six. The reversal underscores how momentum in the quick-service restaurant sector can change when one chain improves traffic and pricing while another struggles to sustain demand.