Despite increasing turmoil around the world, high-net-worth investors in the U.S. remained confident in the economy and the stock market, according to Phoenix Marketing International’s latest tracking survey.

Optimism about the U.S. economy for the next three months held steady at 55 percent among investors with $1 million or more in investable assets, and one-third of those millionaire investors added to their equity positions during the three-month period before the survey was taken in early March.

Wealthy investors also continued to put a priority on allocating assets to retirement accounts, with 33 percent increasing their retirement contribution over the past three months, according to the survey.

“High-net-worth investors are clearly remaining bullish on equities, and don’t seem too concerned about the impact of rising oil prices and other stories in the news,” said David Thompson, managing director of Phoenix’ Affluent Marketing Practice, which conducted the survey of 1,166 investors. “The question is how temporary will these events be? If they persist, we may see a downturn by mid-year.”

Wealth managers said the findings of the Phoenix survey mirrored what they were seeing among their clients.

“We’re not hearing apprehension about the news stories when we talk to clients,” said Richard Trumpler, chief operating officer of New York Private Trust Company. “The market has shown tremendous resilience, and I think that has boosted people’s confidence.”

In Atlanta, Wes French, partner at French, Wolf & Farr, said he also had gotten “few calls of concern” from clients. “With as many issues as there are around the world, it’s surprising, but I think folks are focused more on the U.S., where there’s a perception that things are improving slightly, but consistently.”

Mass affluent investors with $250,000 to $999,000 in investable assets were somewhat less confident, the survey found. Three months ago, 47 percent expressed optimism about the U.S. economy but that number dipped to 41 percent in early March.

“I think millionaires paid much more attention to asset allocation than those with less money,” Thompson said. “They managed risk better and spread their money around to alternatives, real estate and ETFs, and feel more secure as a result.”

The relatively high increase to retirement savings also reflects that confidence among wealthy investors, according to French. “It’s an indication that they have recovered from the financial crisis and think the worst is behind them,” he said. “Now that the world didn’t end, they’re going back to basics and building their nest egg again.”