There’s a new merchandising leader at the world’s biggest retailer. Wal-Mart U.S. has named Duncan Mac Naughton chief merchandising officer, responsible for all merchandise categories across the retailer’s 3,700-plus domestic stores. The appointment is effective immediately. Mac Naughton succeeds John Fleming, who left Wal-Mart in August. Mac Naughton joined Walmart in 2009 as chief merchandising officer of Walmart Canada and was named executive vice president of m...