Walmart’s share gains continued to be mainly driven by upper-income households in the 1Q, the retail giant says. U.S. comparable stores sales excluding fuel rose 3.8% in the period. Still, its average ticket remained flat. Overall in the quarter, Walmart saw strength across all operating segments, with global ecommerce sales growing 21% as a result of its in store-fulfilled pickup and delivery. Shares rise 5.5% to $63.14 in premarket trading.