The "time window is closing" to avoid market disruption, El-Erian said.
At a time when the housing market is booming, El-Erian questioned the need to buy mortgage bonds.
With regard to reduced-size bond purchases, Allianz Chief Economic adviser Mohammed El-Erian advised Federal Reserve Chairman Colin Powell to "act quickly."
The bond mogul has been urging the Fed for months to reduce its asset purchases before inflation rises and hits financial markets. A week ago, Powell said the Fed could start cutting back in November and end bond purchases by mid-2022.
"with regard to orderly subtraction, the time window is closing," El-Erian said on Bloomberg TV's The Open program on Friday.
He believes that the US housing market provides a reason for the Fed to reduce its size as soon as possible.
"We still buy $40 billion a month in mortgage-backed securities (MBS)," El-Erian said. "the problem with the housing market is not that it needs support, but that high prices are shutting Americans out. Americans may no longer be able to afford this level of house prices.
"We are still buying $120 billion a month in assets, and we have been doing this since the height of the epidemic crisis," El-Erian said. Now, when demand is no longer a problem and the bond market is open, is it reasonable to continue to buy bonds? "