While chief executive officer Bill Winters' measures to restructure the lender and boost capital address some concerns, implementing the plan could be challenging because of credit risks and high management and staff turnover, Fitch said in a statement. The ratings firm on Thursday cut the lender's credit rating one grade to A+ from AA-, with a negative outlook. Mr Winters, who took over in June, on Tuesday unveiled 15,000 job losses to help save US$2.9 billion by 2018, with the bank scrapping the second-half dividend. Standard Chartered will also restructure or exit US$100 billion of assets and reduce its riskiest lending in Asia after loan impairments surged. The bank that day reported an unexpected third-quarter loss of US$139 million, compared with a profit of US$1.5 billion a year earlier. BAD LOANS The bank's impaired-loan ratios remain above its peers' and appear to have become more volatile as a result of concentrated sector and country exposures, Fitch said.