By Carlo Versano

After a Christmas Eve plunge that sent the Dow Jones Industrial Average tumbling 650 points, stocks spiked in a massive rally on Wednesday, with the Dow booking the largest single day of point gains in its history.

The tech-heavy Cheddar 50 Index, which measures the performance of Cheddar's 50 top companies ー from Apple ($AAPL) to GM ($GM) ー was up about 9 percent with all 50 stocks in positive territory at the market close on Wednesday.

The Dow gained a staggering 1,086 points Wednesday, or about 5 percent. The S&P 500 also gained 5 percent, while the Nasdaq surged nearly 6 percent higher.

The week between Christmas and the new year, normally a languorous, uneventful few days of thin trading and early closings, is proving to be a continuation of the roller-coaster ride that has rattled investors since the fall.

The wild swings appeared to reflect a new reality: the only thing that is certain in the current financial and political climate is unpredictability.

With the government partially shut down over his demands for a border wall and stuck in the White House over the holidays rather than sunnier Mar-a-Lago, President Trump has reportedly become obsessed with the stock market, viewing it as one of the few true measures of his performance. And as the turmoil that began to infect the financial markets in October has spread, Trump has done little to calm the markets.

Instead, the president has vacillated between a desire to fire Fed chair Jerome Powell, and most recently, Treasury Secretary Steve Mnuchin, whose Christmas Eve statement meant to reassure investors had the opposite effect. Both men appear safe in their jobs, at least for now, according to Daniel Lippman, a Politico reporter who follows the day-to-day machinations of the White House.

Now, with a government shutdown in its fifth day, Trump and the GOP are losing the remaining leverage they have before Democrats take control of the House "by the day," Lippman said.

Despite the political turmoil, Scott Shellady, senior vice president of derivatives for TJM Investments, noted that all signs indicate the U.S. economy is on solid footing.

"It's been a historic sell-off for no real, solid fundamental reason," he told Cheddar Wednesday.

"We haven't had any new news to drive us lower except for the folks who have been banging the recession drum because we've had it too good for too long. That doesn't mean we can't have it good going forward, but we're still worried about the monster under the bed," Shellady said. "And maybe today the lights were on and we looked underneath the bed and [the monster] wasn't there."

With stocks riding a day-to-day roller-coaster, Melissa Armo, founder of The Stock Swoosh, advised investors to sit back and wait rather than jump in. While the fundamentals of the economy are still bullish, Armo said there is too much uncertainty in the air to believe that the last three months of punishing volatility would end any time soon ー even if stocks rally in the last trading days of the year.

"I don't think all of a sudden that one rally is going to reverse all of this," she told Cheddar. "Every time the market has tried to rally, it's failed."

But Armo thinks the D.C. dysfunction isn't imperiling Wall Street to the degree spectators may think. She added the market wouldn't much care about any personnel change in Washington ー except for Trump. She urged House Democrats to think twice about bringing impeachment proceedings against the president, arguing that even despite the volatility, Wall Street has largely been a fan of the Trump presidency.

Politics aside, the year ahead looks rocky from Armo's vantage point. "For 2019, everybody needs to be on their game," she said. "This year is going to look like a lamb, and next year is going to look like a lion" in terms of volatility.

For the private companies planning to ride a hot IPO market, all bets are off. Nicholas Jasinski, who follows IPOs for Barron's, said that the kind of speculative tech unicorns that drove the recent IPO boom are less attractive in a slowdown, when investors are more attracted to companies that show sustained profitability, rather than wild valuations.

"Growth only goes so far," Jasinski said. He is looking to the forthcoming offerings from Uber and Lyft, both expected in 2019, as important indicators of how widespread the fear in the market is. Both of those companies are valued in the tens of billions, yet neither have reached profitability.

He echoed Armo's view that it's "too risky" to "buy the dip" right now, at least until more certainty creeps back into the market.

"In the long-term, stocks will always go up," he said.