Short-term US interest rates turned negative on Thursday as banks stockpiled government securities in order to “window dress” their balance sheets for the year-end, highlighting continuing distortions in the financial system more than a year after the collapse of Lehman Brothers. The scramble has been exacerbated by the fact that all top US banks, many sitting on big trading profits, will this year close their books at the end of December. In past years, top investment banks have reported annual results in November.
