Millionaire investors are adding to their mountains of cash, betting on higher interest rates and weak stock markets in 2023, according to the CNBC Millionaire Survey.

More than a third of millionaire investors, 34%, report keeping more of their money in cash, according to the survey, which surveys households with $1 million or more in investible assets. They now have 24% of their portfolio in cash, up substantially from the 14% they held in cash a year ago, according to the survey.

Of the survey respondents, 28% said they have purchased more fixed income, as they expect interest rates to remain high.

The results echo a recent survey by Capgemini that found global high-net-worth investors had a record 34% of their portfolios in cash or cash equivalents, such as money markets, CDs and other vehicles.

“These investors are moving from growth to value, to protecting their assets,” said Elias Ghanem, global head of Capgemini Research Institute for Financial Services. “Right now, it’s better to be safe than sorry.”

Wealthy investors are still cautious on the stock market, but not as bearish as they were at the start of the year. While 38% of millionaire investors say the S&P 500 will end the year down, a slightly larger portion, 40%, say the market will end the year higher.

That market sentiment has brightened substantially since last year, when 69% of survey respondents expected to end 2023 down and only 22% expected markets to end higher.

“They’re becoming more comfortable with the market volatility and the fact that markets keep going up despite all the reasons it should be going down,” said George Walper, president of Spectrem Group, which conducts the Millionaire Survey with CNBC. “A lot of people are just confused as opposed to predicting further declines.”

Millionaires are more bearish on the overall economy, however. A majority, at 60%, expect the economy to be “weaker” or “much weaker” at the end of 2023.

One reason for their caution: inflation. Millionaire investors are still betting inflation will persist for years, potentially keeping interest rates higher for longer. More than half of millionaires say inflation will not fall to the Federal Reserve’s 2% target for at least two years, with 11% saying it will last at least five years.

There are wide disparities by generation, since an inflationary stock market and economy are new phenomena for younger investors. Three-quarters of millennial millionaires say inflation will come down to 2% within two years, with one in four saying it will hit the 2% target within a year. That compares with 59% of older investors who say it will take longer than two years.

“They haven’t experienced rate increases and inflation like this,” Walper said.

Inflation and higher interest rates are starting to affect the spending of the wealthy, although the changes are still small. More than a third of millionaire investors have cut back on restaurant spending over the past six months due to inflation, according to the survey, and 18% have delayed the purchase of a car. More than one in four millionaire investors say they have given less to charity because of inflation, suggesting higher prices could also affect giving.

If inflation persists, a growing number of millionaires, 18% of respondents, say they will cancel a trip or vacation, according to the survey. They’re also borrowing less, with a third saying they plan to borrow less this year due to higher rates.

One bright spot for millionaires is bank deposits. Despite the turmoil in the regional banking system, with the failures of Silicon Valley Bank, First Republic and Signature Bank, more than two-thirds of millionaires say they are not concerned or are “neutral” about the safety of their deposits at banks. Only 7% said they were “very concerned.”

Just 6% of millionaires surveyed moved cash deposits out of a bank because of the SVB collapse. Yet, two-thirds of millionaires support Congress raising the limit on cash deposits as regulated by the Federal Deposit Insurance Corporation.

“They saw the government take action quickly, so they were not as worried,” Walper said.

CNBC’s Millionaire Survey was conducted online in April. A total of 764 respondents, with $1 million or more of investable assets, qualified for the survey. Respondents had to be the financial decision-maker or share jointly in financial decision-making within the household. The survey is conducted twice per year, in the spring and the fall.