Treasury Secretary Steven Mnuchin's comments Friday didn't lift investor sentiment. He defended his decision to end the Federal Reserve's key pandemic lending programs on December 31.

Financial stocks such as JPMorgan Chase and Visa helped drag the Dow and S&P 500 lower. Microsoft, Amazon and Facebook weighed on the Nasdaq. Shares of Pfizer and BioNTech rose. Pfizer said it'll apply to U.S. health regulators to permit emergency use of the COVID-19 vaccine it developed with its German partner, BioNTech. But the latest positive developments on vaccines this week haven't been able to drive the S&P 500 beyond the all-time high it hit Monday.

Thomson Reuters Stocks Buzz Analyst, Terence Gabriel:

"Even with the additional positive news we have seen on the vaccine front, we.have yet to move above that high. So it does seem as if it's struggling here, perhaps internally overheated and focused though stimulus."

Shares of Gilead Sciences fell. A World Health Organization panel said Gilead's antiviral drug, remdesivir, should not be used for hospitalized COVID-19 patients, saying there's no evidence the drug improves survival or reduces the need for ventilation.