Rivals Target and Walmart have long been considered polar opposites. The biggest difference lately, though, is financial performance, underscored by the retailers' earnings reports this week.

As of Thursday’s close, shares of Walmart were up 114% over the past three years, while those of Target have slid 42%. Following their most recent quarterly earnings this week, analysts pointed to a variety of reasons for that gulf — from the practical and financial to the existential.