Rich, young women are kicking butt.

Wealthy Millennial women are more likely to make at least as much -- if not more -- than their husbands. They're also more likely to take the big decisions on household finances and investments, according to a new report from U.S. Trust that surveyed high and ultra-high net worth individuals, defined as those with at least $3 million in investable assets.

The report found that 30% of these wealthy Millennial women were the primary income earners, and another 21% contributed the same amount as their partners. That's compared to just 11% of Gen X women who made more than their husbands, 15% of Baby Boomer women and 4% who are 70 years old or older. The percentage of equal earners remained relatively similar across all four generations.

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Not only are the high net worth Millennial women earning more than women in other generations, but they're also making more financial decisions than older women. In fact, in a major generational shift, they're making more financial decisions than their husbands.

For Millennial women, 31% are the dominant decision-makers when it comes to household finances, compared to 28% of men, just 11% of Gen X women, 9% of Boomer ladies and 1% of what the report calls "mature" females. The breakdowns, and the vast shift from generation to generation, are nearly identical when it comes to investment decisions.

Younger wealthy women are also seeing a great change when it comes to childcare. The report found that while women across the board still act as the primary caregivers for children, Millennial men are taking on a far greater share of the responsibility than men of older generations.

About 25% of Millennial men surveyed said they are the primary caretakers to children in their household. Only 7% of Gen X men, 3% of Baby Boomers and 4% of mature men said the same.

Because younger women have greater earning and decision-making power among this wealth segment, U.S. Trust is seeing more females interested in planning and investing wealth, according to Chris Heilmann, chief fiduciary executive at the bank.

"We tell our employees that if you have clients who are married couples and you're primarily talking to the husband, you have to change that," he said.

The report is based on a national survey of 640 high-net-worth and ultra-high-net-worth adults, 16% of whom identified as Millennials.