LOS ANGELES—After weeks of speculation within the music industry, English folk-rock group Mumford and Sons took home the big prize at Sunday’s 55th Annual Grammy Awards by winning the highly coveted Vest of the Year trophy. “Wow, I don’t even know where to begin,” said lead singer Marcus Mumford, after his slim-cut russet waistcoat secured the band its third win on a night in which the quartet also collected statuettes for Watch Chain of the Year and Best New Straw Hat. “We never could have imagined it. I mean, just to have our vest nominated alongside all these other amazing vests—it’s really a dream come true.” Following Mumford and Sons’ victory in the vest category, the band narrowly missed sweeping the Grammys’ four major apparel awards after losing out to indie pop trio fun. for its upbeat, critically acclaimed suspenders.