You know an economy isn’t healthy when banks are using as much of their money to buy government debt as they are to make loans to businesses. That’s just what’s happening right now. According to the Federal Reserve ’s latest weekly measure of bank assets and liabilities, released every Friday, banks held 1.37 trillion of Treasury and Fannie Mae or Freddie Mac debt securities at the end of October and $1.37 trillion of commercial and industrial loans.