A sell-off of healthcare stocks sent the markets into a tailspin with the Dow tanking 362 points to 26,076. Nasdaq plunged 64 points to 7402.

On the upside

Aquantia (NYSE: AQ) will provide its Multi-Gig chipset solution for Nvidia's (Nasdaq: NVDA) autonomous vehicle DRIVE Xavier and DRIVE Pegasus platforms.

The Food and Drug Administration upgraded the designation of Pfizer's (NYSE: PFE) McPherson facility as Voluntary Action Indicated which clears a path for the marketing approval of Achaogen's (Nasdaq: AKAO) plazomicin.

Extreme Networks (Nasdaq: EXTR) will replace Time (NYSE: TIME) on the S&P SmallCap 600 before market open on February 1, 2018.

On the downside

Fourth quarter earnings plunged for Polaris Industries (NYSE: PII).

AK Steel (NYSE: AKS) widened fourth quarter losses more than expected.

Integrated Device Technology (Nasdaq: IDTI) fell to a loss for the third quarter.

In the broad market, declining issues outpaced advancers by a margin of more than 4 to 1 on the NYSE and by nearly 3 to 1 on Nasdaq. The broader S&P 500 plummeted 31 points to 2,832. Bitcoin crashed $954 to $10,071.