Financial Winners & Losers: Citigroup

In a note to clients Friday, Citi Investment Research analyst Keith Horowitz said commercial real estate is quickly becoming a bigger issue for the New York-based bank.

"Commercial real estate fundamentals are deteriorating both from the demand side as an economic downturn reduces need for space and lower valuations due to tighter/more expensive credit availability," Horowitz wrote.

As of Sept. 30, JPMorgan held $9.3 billion of what he sees as "risk" commercial mortgage-backed securities in its investment bank. Horowitz estimates that JPMorgan could mark down $300 million to $400 million on this portfolio.

Bank of America (BAC Quote) shares were down 50 cents, or 4.4%, to $10.75, a day after falling 10% Thursday, while Wells Fargo (WB Quote) shares fell $1.30, or 5.8%, to $21.23 in afternoon trading.