Walmart Inc’s urgency to stem market share losses to rivals around the world is driving it to partner with local players in the UK and India, even as it scales back in some other markets like Brazil. The world’s largest retailer is in talks to merge its UK arm ASDA with J Sainsbury Plc in which it will hold a minority stake. Walmart is also looking to acquire a majority stake in India’s leading online retailer Flipkart for $10 billion to $12 billion after years of underperformance there.