Deutsche Bank analyst Jeremy Kliewer downgraded Century Aluminum to Hold from Buy and lowered his price target for the shares to $15 from $20. Century's margins could remain pressured for longer due to alumina supply disruptions, Kliewer tells investors in a research note. Further, the analyst feels little progress has been made with Santee Cooper, the electrical supplier at the company's Mt. Holly smelter, and that support for import tariffs may decline further following the November mid-term elections. As such, the analyst sees reduced upside potential and growing risk for Century Aluminum shares.