Early Tuesday, Bill Gross took to Twitter, commenting on the speech given Monday by New York Fed president Bill Dudley.
Gross noted that Dudley thinks that while the natural interest rate - or the rate at which the Fed's inflation and employment objectives are achieved - may be lower than they've been historically going forward, this rate could still be 3%-4%.
Interest rates are currently at 0%-0.25%.
Gross wrote that if Dudley is right about the natural interest rate, then bonds are overpriced by 2%-3%.
On Tuesday morning, the US 10-year yield was around 2.2% and the 30-year bond was near 3%.
Gross' comments come after Jeff Gundlach, who has usurped Gross as the "Bong King," told CNBC that Treasury bonds still look relatively cheap.
In the past, Gundlach has said that he doesn't think the Fed has any plans to raise rates.
And while last week Gundlach told CNBC that he thinks the Fed might raise rates next year "just to see what happens," he added that with Spanish 10-year bonds yielding less than 2% it seems "almost unthinkable" that US Treasury yields would rise.
Gross, who unexpectedly left PIMCO back in September, did meet with Gundlach about joining his firm, DoubleLine Capital, but the two decided not to join forces.
Gundlach told CNBC that Gross joining DoubleLine was "sort of a 50-50 kind of proposition," but said that ultimately, he is okay with the decision because had investors asked him, after signing Gross, what the move meant for DoubleLine, he answer would have been, "I don't know."
Divergent views within a firm are common, if not healthy.
But Gundlach and Gross are the two biggest names in the bond world, and so given their split view of the bond market, maybe it's better that they're not working together.