LONDON—Walmart Inc. on Monday said it would sell its British arm Asda Group Ltd. to rival J Sainsbury PLC, a deal that values the chain at about £7.3 billion ($10.1 billion) and, if successful, would create the U.K.’s largest grocer.
Walmart will hold a 42% stake in the combined company and get almost £3 billion in cash. The Bentonville, Ark. company will have voting rights up to 29.9%.
If...