The Federal Reserve's economic stimulus program has not been priced into the financial markets, UBS' Art Cashin told CNBC.
"You have to be a little careful here," Cashin said on "Squawk on the Street" on Wednesday. "The fulcrum point will be the bond market. A lot of people are trying to say, 'Well everybody knows tapering is coming, so it's priced in the market.' It is not priced in the market."
Cashin, UBS' director of floor operations at the New York Stock Exchange, said he was concerned about traders on margin "panicking.' A spike in bond yields and rates could result as investors try to anticipate the next move from the Federal Reserve and when it begins to scale down its $85-billion-a-month bond buying program.
(Read more: The Fed has created a huge global bubble: Stockman)