SIG

Signet Jewelers Limited

The world's largest retailer of diamond jewelry, Signet Jewelers runs well-known brands like Kay Jewelers, Zales, and Jared across the US, Canada, UK, and Ireland. The company began in 1949 as a single London shop opened by Leslie Ratner, growing through acquisitions into a global chain. Its name comes from the signet ring, a seal used to stamp documents — adopted in 1993 after the company rebranded from the Ratners Group following its CEO's infamous joke calling his own products "total crap."