U.S. equities are being pressured once again by falling oil prices, Art Cashin, UBS' director of floor operations, said Monday.
"If WTI breaks below $37, it will put some extra weight on the market. I think they're still trying to absorb those two big up days that they had. We may have cheated Santa Claus out of a couple of days by doing that," Cashin told CNBC's "Squawk on the Street."
U.S. crude prices fell more than 3 percent Monday, trading at around $36.90 a barrel, struggling to hold on to its premium on Brent. The sharp move lower comes after WTI futures closed sharply higher on both Wednesday and Thursday. (All financial markets were closed Friday due to the Christmas holiday.)
Brent and WTI remain 45 percent and 39 percent lower for the year, respectively.