In the lead-up to the Australia Day long weekend, National Australia Bank continued to be the focus of attention, with the bank expected to update the market next week on the extent of losses racked up in unauthorised foreign exchange losses. On Friday NAB shares rose 5c to $29.59 as the ratings agency Standard & Poors moved the bank's credit rating to negative outlook from stable. The future ownership of News Corp also became the subject of increased speculation after the US media magnate and chairman of Liberty Media, John Malone, moved to acquire a 9.15 per cent voting stake in the company.