Bonds had rallied during the day but turned lower in the last hour of trading, as did the stock market.
But bonds rallied on another signal that the economy is slowing.
"That should not allow bonds to rally much further."
In fact, bonds rallied, with yields dropping to 6.04 percent.
As the stock market fell, bonds rallied, pushing yields lower.
But because the new bond has rallied so much they need to buy it back to prevent sharp losses.
An even bigger surprise, he added, was that "bonds rallied when they weren't supposed to."
C1 Stocks and bonds rallied, mainly on the news that fewer jobs than expected were created last month.
The study said bonds rallied on anticipation of a further easing in interest rates.
He thinks these bonds, which were hit hard as speculators dumped them, will rally.