It’s hard to argue with the risks the famed investor sees from rising US debt, but bonds are an important piece of a balanced portfolio.

The billionaire investor and PIMCO co-founder wrote in a note on Thursday that the US fiscal deficit, largely driven by a massive rollout of Treasury bonds, is now deemed a "necessity" to propel the economy forward, which is fueling upward pressure on bond yields.

Famed bond investor Bill Gross says the “Total Return” investment strategy he helped create in the late-80s is “dead.” The retired co-founder of fixed-income specialist Pacific Investment Management Co.

Bill Gross, who pioneered the “total return” strategy in the 1980s that revolutionized the bond market, says the approach is now defunct.