The stock market has left many investors struggling to catch their breath.
Just last Wednesday, the Dow Jones Industrial Average gained a record 1,086 points, after sliding 653 points on Christmas Eve. And there were many more days, when the markets swung by hundreds of points. In general, 2018 was a unusually bumpy year for markets.
And the gyrations are unlikely to end anytime soon, says Lawrence White, an economics professor at New York University's Stern School of Business.
"It really feels to me like this is a buckle-your-seat-belt, we've-got-turbulence-ahead kind of situation," he says. "The markets are always trying to anticipate what's going to happen in the future, and I think a lot of the uneasiness is this concern about future turbulence."
Although the Dow and the S&P 500 each gained about 1 percent on Monday, all of the major indexes have ended the year down sharply. The Dow is 5.6 percent lower, while the S&P 500 index has dropped by 6.2 percent.
What happened? Signs of trouble first emerged early in the year, with a Labor Department report showing that wage growth was finally picking up, says Quincy Krosby, Prudential's chief market strategist.
"You would think that this would be great for the market," she says. But higher wages can hurt corporate profits and a send a signal to the Federal Reserve that higher inflation is coming.
The Fed had been raising interest rates slowly for two years, but the strong numbers suggested it might keep doing so — and at a faster rate than before. Fed Chairman Jerome Powell added to those fears in October with comments suggesting more hikes were coming.
Stocks have been especially volatile during the last three months of 2018, with some of the big technology companies like Apple and Facebook down more than 20 percent.
President Trump has made the turmoil worse, NYU's White says. "I think the administration has become even more erratic in both its statements and its actions," White says.
Trump has repeatedly attacked the Fed for raising interest rates, and has singled out Powell, whom he appointed to his job, for criticism.
"I put him in, and so far I'm disappointed," Trump said in an October interview on 60 Minutes. "Maybe someday I'll think he's the greatest, but right now I'm very disappointed."
Meanwhile, the Trump administration's aggressive efforts to overhaul U.S. trade policy have only contributed to investor anxiety.
The ongoing tariff war with Beijing in particular raises questions about the economy's near-term performance, because many U.S. companies do substantial business in China or depend on its supply chains to build and sell products.
Technology giants like Apple, Google and Facebook, which account for a growing share of the stock market's daily trading volume, have been especially hard hit by the market drop.
The concern isn't just about trade; tech giants also face a growing risk of government regulation. Facebook, for example, has suffered huge public relations fallout amid revelations that its customers' personal data was used by the political research firm Cambridge Analytica.
All this market volatility is causing headaches for investors, especially those trying to just get a handle on retirement accounts.
Barbara Egeler-Bailey has been caught in the turmoil.
After her parents died, she spent a lot of time fixing up their house near Grand Rapids, Mich., intending to sell it and use the proceeds to help fund her retirement.
After the sale went through in September, Egeler-Bailey put part of the money in a stock fund that invested in medium-risk equities. It was a decision she's come to regret.
"After the stock market here started going up and down like a roller coaster, I saw that my fund had just dropped like 20 percent, dramatically, just since this fall," she says.