The stocks making the biggest moves in premarket trading include Walmart, Uber, Amazon, Shake Shack, and more. : Walmart (WMT) – The retailer announced the sale of its British supermarket chain Asda for $8.8 billion. The buying group consists of private equity firm TDR Capital and the Issa brothers, founders of gasoline station chain EG Group. Uber Technologies (UBER) – Private equity firm Greenbriar Equity will invest $500 million in Uber's logistics unit Uber Freight, valuing it at $3.3 billion. Uber will maintain majority ownership of that business.