Fed study puts ideal interest rate at -5% By Krishna Guha in Washington Published: April 27 2009 03:00 | Last updated: April 27 2009 03:00 The ideal interest rate for the US economy in current conditions would be minus 5 per cent, according to internal analysis prepared for the Federal Reserve's last policy meeting. The analysis was based on a so-called Taylor-rule approach that estimates an appropriate interest rate based on unemployment and inflation. A central bank cannot cut interest rates below zero. However, the staff research suggests the Fed should maintain unconventional policies that provide stimulus roughly equivalent to...