UK banks were trading in the red on Thursday after Exane BNP Paribas speculated that lenders may need to raise more capital to meet regulatory requirements.The Prudential Regulation Authority (PRA), due to make its final statement in December, could introduce additional capital buffers on top of current regulation, raising the fully loaded equity tier-1 ratio to 13% "over time". Analysts believe that Lloyds (rated 'outperform') is the only UK bank that is likely to reach a 13% fully loaded equity ratio by 2015.Canaccord Genuity has upgraded its rating for SABMiller from 'sell' to 'hold' after an 'improved performance' during the drinks group's first half.The broker said that SABMiller has "defied the more extreme emerging-market sceptics" by reporting that volume and revenue growth had picked up in the three months to September.HSBC has raised its recommendation for Chile-based copper mining group Antofagasta from 'neutral' to 'overweight' as it lifted its target price for the commodity.The bank reportedly raised its 2014 forecast for copper from $7,250 to $7,750 a metric tonne, saying that supply concerns have been "overdone".BC