New York (CNN Business) The growing popularity of co-working spaces like WeWork could pose a risk to the US economy in the next economic downturn, a Fed official warned on Friday.

Boston Federal Reserve Bank President Eric Rosengren, who has publicly dissented with the Fed's recent interest rate cuts, said lower rates will boost risk in "unexpected places."

"Evolving market models, along with low interest rates, are creating a new type of potential financial stability risk in commercial real estate," he said at an event in New York City. "One such market model is the development of co-working spaces in many major urban office markets."

Rosengren did not name WeWork or any other co-working company by name, but said he believes the model exposes property owners to the possibility of runs and vacancies. That's because co-working spaces tend to sign long-term leases with the landlord, and then re-lease the spaces to smaller, less-established companies that would be "particularly susceptible to an economic downturn."

"Thus, in a downturn the co-working company would be exposed to the loss of tenant income, which puts both them and the property owner at risk if they cannot make lease payments to the owner of the building," he said.

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