US retail giant Wal-Mart is now seen as the most likely contender to buy Ahold's Bompreco supermarket chain, despite earlier doubts about whether Wal-Mart would make a serious bid for the chain. "In the beginning nobody thought this could happen," Basilio Ramalho, a retail sector analyst with Unibanco in Sao Paulo, was quoted by Dow Jones as saying. "Nowadays a lot of people, and not just analysts, say they hear Wal-Mart will be the most aggressive bidder."