The Dow rallied 236 points but that was just a mere fraction of Friday's decline - the worst all year.

The S&P 500 rose 60 points.

And with a gain of 291 points the Nasdaq nearly took back all off Friday's losses.

David Bahnsen, chief investment officer at The Bahnsen Group said Friday's nosedive was an over-reaction.

"Just as much as I'm somewhat sanguine on what the variant news will end up being, there's still a lot of uncertainty too, so some people still may not want to get fully back into the water. They want to wait and hear some additional information. But I think that the headline issue Friday drove some panic selling. And now you have a partial normalization playing out today."

A rebound in the price of oil gave energy stocks a boost. Top officials from OPEC and OPEC+ said they weren't worried that the new COVID-19 variant Omicron would dampen demand. Crude oil prices climbed and so did the stock price for oil majors like ExxonMobil.

Retailers were a key sector to watch as Cyber Monday got underway. There were some concerns after Black Friday posted the first-ever drop in digital sales compared to the prior year. But other early indications on the start of the key holiday shopping season were less somber. U.S. shoppers spent 14% more on merchandise excluding automobiles during Black Friday weekend compared to the same holiday weekend a year earlier, according to MasterCard SpendingPulse. Shares of e-commerce leader Amazon rallied 1.6 percent on the day.

Twitter had a volatile day. Jack Dorsey announced he stepped down as CEO and was replaced by Chief Technology Officer Parag Agrawal. Shares ended the day lower after an initial pop.