Bill Gross, manager of the world's largest bond fund, sold his entire holding of US government bonds due to concerns about unsustainably low interest rates and rising government debt levels. The US debt as a percentage of GDP is rising sharply, last seen during WWII. With interest rates already low, bond investors face risks from either rising inflation or higher interest rates. Selling bonds now may be the last chance to exit before significant losses. The dollar's value is also threatened by rising debt and money supply.