The major averages fell sharply on Friday, wiping out the Dow Jones Industrial Average's gain for January, as investors grew increasingly worried about the potential economic impact of China's fast-spreading coronavirus. The Dow dropped 603 points, or 2.1%, to 28,256, its worst day since August. The S&P 500 had its worst day since October, falling 1.8% to 3,225. The Nasdaq Composite dropped 1.6% to 9,150.

On Friday, the U.S. declared the coronavirus a public health emergency within the country. Delta, American and United suspended all flights between China and the U.S. The virus, which was first discovered in the Chinese city of Wuhan, has now spread to at least 18 other countries and has dampened sentiment over global economic growth. China's National Health Commission confirmed on Friday that there have been 9,692 confirmed cases of the coronavirus, with 213 deaths.

Ten of the 11 S&P 500 sectors finished lower, including six that lost at least 2.0%. The energy sector (-3.2%) bore the brunt of the damage as the worst performing sector year to date. Exxon Mobil and Chevron closed lower by 3.8% or more following earnings. Caterpillar, Visa, World Wrestling Entertainment and Illinois Tools Works were also lower following earnings.

The diamond today was Amazon closing up 7% following strong earnings. IBM jumped 5% on news their CEO is stepping down.

The 2-yr yield fell seven basis points to 1.32%, and the 10-yr yield fell four basis points to 1.52%. The U.S. Dollar Index fell 0.5% to 97.38.

For the month, the S&P 500 closed marginally lower for January, snapping a four-month winning streak. The Dow also had its first monthly loss since August. The Nasdaq posted a 2% gain in January, its fifth-straight monthly advance thanks to Apple, Google, Amazon and Microsoft.