Bill Tiedemann is keeping a close eye on his retirement accounts these days.

The 66-year-old knows better than to make knee-jerk changes to the long-term plan. But a nosediving stock market still spurred some anxiety in him last month, as President Donald Trump's evolving but turbulent tariff policy caused wider strife among investors.

At its worst, near Liberation Day on April 2, Tiedemann estimates his investments lost about 20% in value. In the weeks since, while U.S. stocks have seen major recovery amid a cooling trade war, he says they are now up about 5%.

"I think we all are anxious," Tiedemann said. "But if you are smart with your investments, you don't move them."

Many investors are breathing a sigh of relief as the S&P 500 returned to profitable territory this week, wiping out losses that had piled up since its February highpoint. Still in the red this year are the tech-heavy Nasdaq and the Dow Jones Industrial Average, though both are closer to regaining the same ground held in January.

Months before sweeping tariff policies roiled the stock market, Thrivent Chief Financial and Investment Officer David Royal expected greater volatility this year. The executive at the Minneapolis-based financial services provider based his theory on last year's relatively low volatility, paired with increased pressure on the Fed to keep inflation in check and the job economy strong.

Although tariffs have been a driver, Royal said simultaneous risks of inflation and reduced economic growth expectations "caused even more volatility than I or probably anyone envisioned." He said it typically takes longer for economic weaknesses to show up in data than inflation, potentially making it "very easy for (the Fed) to get behind the curve."

Royal has predicted conservative growth in the stock market for the full year.

"But it's going to feel like you've gone through a roller coaster ride," Royal said. "I think that's what we're seeing this year: The mirror image of last year."

Such outlooks are likely to test the mettle of people who are building 401(k) plans or depending on them for retirement.

Lou Anne Sexton, 63, of Mendota Heights, retired from St. Thomas University in January and lately has wondered if it was the right call, financially speaking. Future uncertainty and volatility is a concern, she said, since she recently began to rely on her 401(k) to deliver.

She said she and her husband meet regularly with their financial adviser to ask if they should change anything. The response so far: "Ride this out."

It is in times like these that financial advisers can prove their value, said Bertie Cayzer, a senior portfolio manager at Plymouth-based Wealth Enhancement Group.

Outside of a few overreactions, Cayzer said his firm has yet to hear much concern from the clients. Those properly managed in the latter stages of working life should really have no worries, he said, and the bouts of volatility offer opportunities to invest in cheaper equities and diversify.

An advisor doing the work should help clients find their tolerance for risk and plan appropriately for their lifestyle. And at this point, "optimism and realism should counter pessimism," Cayzer said.

Though 401(k) holders often set-and-forget their investment strategies, more people altered positions this year in apparent reaction to tariff-induced downturns, according to analytics firm Alight Solutions in Chicago.

Alight, which maintains an index of 401(k) trading data back to 1997, recorded a shift away from equities like stocks and toward fixed-income mutual funds that rely on bonds for more conservative growth. Overall trading activity was higher than normal throughout the first quarter.

Above-average trading levels persisted in early April as the U.S. trade war escalated. Investors left equities and later bought back in on the rebound, said Rob Austin, Alight's head of thought leadership.

Still, such trading among 401(k) holders represents a small margin of the widely used retirement plan, Austin said, as in absolute terms only a fraction of a percentage point is traded on a given day.

On the Monday after Liberation Day, Austin said retirement investors showed approximately 10 times the normal level of trading activity.

Experienced investors know the market will drop time and again and stay the course, Austin said, but for those "who did take action, it's going to look really, really bad."

"This year is really a microcosm of everything" we typically see, Austin said, adding "people are very quick to sell out of equities when the market drops" and it often takes time before comfort returns to buy back in.

Meantime, some Minnesotans are taking the swings in stride.

"I don't get anxiety over it," Brian Haan, 39, of Lakeville, said of the roller-coaster stock market. "I hold my nose, and I know that it will go back up."

Mary Schmidt, 80, of Bloomington, and her husband are past the point of relying heavy on stocks. She has no sleepless nights when the market takes wild turns.

"We kept ours as-is," Schmidt said. "We're diversified."