Signet Jewelers Limited is the world's leading retailer of diamond jewelry. Blue Nile, Inc. is a leading online retailer of high-quality, conflict-free, GIA graded diamonds and fine jewelry.

Blue Nile has had an interesting history over the years both going public and being taken private, but still there is no one in the online jewelry market that matches its reach.  The tie-up was in some ways inevitable at some point given the margin pressures of purely online retail.

CNBC: Zales owner Signet buys online jewelry brand Blue Nile to bolster its portfolio