In its Billionaire Bonanza report, the think tank called the growing wealth inequality in the U.S. a “moral crisis” and warned that the tax policy proposed by the Trump administration would only worsen the disparity, with 80% of tax benefits going to the wealthiest 1% of households.

Citing the rise in wealth inequality, economist and co-author of the report Chuck Collins said, “Now is the time for actions that reduce inequality, not tax cuts for the very wealthy.”

The report found that the wealthiest 400 people in the U.S., based on a Forbes magazine list, have more combined wealth than the bottom 64% of Americans.

“We have not witnessed such extreme levels of concentrated wealth and power since the first gilded age a century ago,” the report says.

The Forbes list cites Gates, the Microsoft founder, as the richest person in America with $89 billion, Amazon’s Bezos as second richest with $81.5 billion, and investor Warren Buffett at third-richest with $78 billion. Since the list was published, Bezos’s wealth has increased — thanks in large part to the rising value of Amazon’s stock — putting him at nearly $100 billion and in a position to appear at the top of the Forbes list next year.

Bezos, in particular, demonstrates a key point of the report: The super rich are accumulating wealth faster, making it harder and harder to break into the club.

Wages for workers in the U.S. have remained relatively stagnant in recent years, while chief executive officers’ compensation has grown more than 930% since 1978. CEOs now make 271 times what the typical worker earns.

This year the Forbes magazine list of the 400 richest people in the U.S. saw an 18% increase in the amount of wealth needed to make the cut. The price of admission is now $2 billion — ten times the amount of money it took to make the first Forbes 400 list in 1982.

Meanwhile, one in five U.S. households have zero or negative wealth. This is especially true of minority households — nearly a third of black households and more than a quarter of all Latinx households have zero or negative wealth, compared to 14% of white families.

“Such staggering levels of wealth inequality threaten our democracy, compound racial and class divisions, undermine social cohesion, and destabilize our economy,” the report says.

The top 25 richest billionaires are all white. There are only two African Americans (Oprah Winfrey and tech investor Robert Smith) and five Latinx members among the 400-person list.