While the Covid crisis has boosted the wealth of many of the richest Americans, it has made some reconsider their holiday spending.

Nearly a quarter of millionaires surveyed for CNBC's Millionaire Study said they'd spend less this year compared to the 2019 holiday season. At the same time, 65% said they'd spend about the same amount, and 12% planned to spend more.

The survey was conducted in November by Spectrem Group on CNBC's behalf, and included 750 participants with $1 million or more in investible assets.

There is other evidence that millionaires are slashing their holiday budgets. This year, 27% said they planned to spend less than $500, an uptick of six percentage points from 2019.

Health crisis weighs on spending by the wealthy

To be sure, the reason the wealthy have cut down holiday spending is likely not because they have a lack of funds. Year to date, the stock market has risen roughly 15% through Dec. 17.

Instead, lower holiday spending in 2020 is more likely tied to the health crisis. More than 80% of the millionaires surveyed said they are more worried about the pandemic and its impact on health than their financial situation.

"They have money to spend and they can't spend it," said certified financial planner Cathy Curtis, founder and chief executive officer of Curtis Financial Planning, an Oakland, California, firm that specializes in the finances of women and their families. She added that, for many, travel has been put off this year. That's especially impacting the holidays, especially for those that don't have local family, she said.

There is one silver lining, according to Curtis: Many of her clients have increased their charitable giving amid the pandemic.

"Because of Covid and the income inequities and the people that are being hurt, a lot of people are giving a lot more money to food banks than ever before because they feel like that's where they can do the most good," she said.

How the holidays are shaping up for the rest of us

Those who don't have $1 million or more in assets are facing a very different reality this holiday season. For more than 40% of U.S. households, income is still below pre-pandemic levels, according to a recent Bankrate survey of 2,750 adults.

That's having a big impact on holiday spending. Nearly 1 in 3 people plan to forgo gifts altogether because of Covid, according to WalletHub's 2020 Holiday Spending Survey. In addition, almost 102 million consumers plan to spend less this year on the holidays than they did in 2019.

The coronavirus pandemic has been an outsized burden on those least able to bear it, including low-income workers, those who have been laid off, people of color and women.

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There's also increased uncertainty heading into the end of the year. Millions of Americans are relying on Congress to pass another coronavirus relief bill to extend programs such as unemployment insurance or a ban on evictions and send another round of stimulus checks to households next year.

And even with a relief bill, a lot of Americans may see a gap in benefits, as many programs established by the CARES Act this spring will expire at the end of December.

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Disclosure: NBCUniversal and Comcast Ventures are investors in Acorns.