Moody's Investors Service lowered the credit ratings of 15 major banks on Thursday, including Bank of America, JPMorgan Chase and Goldman Sachs, saying their long-term prospects for profitability and growth are shrinking. In its latest report, Moody's didn't treat all large banks alike. It sorted the banks it was downgrading into three categories, with JPMorgan, HSBC, and Royal Bank of Canada in the top one. Moody's said those firms have stable businesses that offset losses from the volatile markets businesses. JPMorgan, for example, has a large base of consumer deposits and major lending, credit card and asset management businesses. These banks have also managed to contain their exposure to risky European government debt, Moody's said. While all three were downgraded, their debt had the highest ratings among the 15 banks affected. The second group included Goldman Sachs, Deutsche Bank and Credit Suisse.