Millionaire kids to inherit most of their parents' fortunes

American millionaires plan to leave the vast majority of their wealth to their kids, giving less than 10 percent to charity, according to a new survey.

The CNBC Millionaire Survey, which polled Americans with a net worth of $1 million or more, found that more than half plan to leave each of their children $1 million or more. One in four plans to leave the kids at least $500,000 and only 4 percent plan to leave their kids less than $100,000.

Among those with $5 million or more in wealth, 88 percent plan to leave each of their kids at least $1 million and one in five plan to leave their kids at least $100 million.

The numbers point to a massive cascade of wealth that could pour down from parents to their kids in the coming decades. They also stand in stark contrast to high-profile megadonors such as Warren Buffett and Bill Gates, who have said they plan to leave almost all of their fortune to charity.

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"This shows that the very visible people who say they're going to leave it all to charity are not very representative of the mainstream wealthy," said George Walper, president of Spectrem Group, which conducted the survey of 750 millionaires for CNBC. "These results are far more typical of historical trends, where people who are wealthy want to take care of their children and grandchildren, and they're not ashamed of that fact."

Estimates vary widely on how much money will pass down through the generations in the coming years. The consulting firm Accenture estimates that $30 trillion could be passed down from one generation to the next in the coming decades, while the Boston College Center on Wealth and Philanthropy estimates the windfall at $59 trillion.

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Either way, charities may not receive as much as some have predicted. When asked how much of their wealth they plan to leave for charity, two-thirds of the millionaires in the CNBC survey said they planned to leave less than 10 percent of their wealth to charitable causes. One in five of them plan to leave nothing to charity.

At the same time, today's millionaires are putting few restrictions on how their kids spend their inheritances. And they believe that there is no such thing as "too much" when it comes to leaving money for their kids.

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When asked "how much is too much" to give to their kids, the majority (59 percent) said there is "no such thing as too much." When asked to describe their attitudes about inheritance, the largest number (41 percent) agreed with the statement that "I want to leave my children as much money as possible and I am confident they will be responsible with the money." Only 17 percent agreed with the statement that they will be "cautious in how much I give my children because I believe they need to learn to be self-reliant."

Fully 84 percent said they do not plan to specify to their kids what their inheritances should be used for.

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When asked what age their children were when they were told about their inheritance, the largest number—44 percent—said they haven't told their kids yet. One in five said their kids would be 30 or older before they were told about their inheritances and 20 percent said the age would be 20 to 29.

Walper said today's wealthy and their kids are far more educated when it comes to managing and preserving wealth, and that risks of a whole generation of free-spending Paris Hiltons are overblown.

"As more wealth is being passed down through the generations, it will be more thoughtfully passed down," he said. "It's also about passing down values along with the money."