UK retailers Asda and Sainsbury have dismissed rumours that they are mulling a joint bid for sector rival Safeway as pure speculation. A report in The Business newspaper yesterday [Sunday] claimed that Sainsbury, the UK's second-largest supermarket operator, and Wal-Mart subsidiary Asda, the third-largest grocer in the UK, have held talks about how they might carve up Safeway. The paper said Asda wanted to take Safeway's larger stores while Sainsbury would take the high-street portfolio.