In an open letter to all Presidential contenders, 18 US-billionaires are calling for a wealth tax on the super-rich to address inequality and climate change. The signatories include investor George Soros, Chris Hughes, Molly Munger, Abigail Disney, Liesel Pritzker Simmon, Agnes Gund, Arnold S. Hiatt, Justin Rosenstein, and Stephen M.Silberstein.

According to the OECD, the US has the sixth highest concentration of wealth among its 40 member states. According to a recent Federal Reserve report, the wealthiest 1% of Americans accumulated wealth to the tune of $21 trillion, while the bottom 50% has seen its assets fall in value by $900bn. According to a Hill HarrisX poll published in February, taxing the rich has the support of 74% of Americans, including 65% of Republicans.

“A wealth tax could help address the climate crisis, improve the economy, improve health outcomes, fairly create opportunity, and strengthen our democratic freedoms. Instituting a wealth tax is in the interest of our republic,” their open letter reads.

Becoming more specific as to the danger to democracy, the signatories note that “division and dissatisfaction are exacerbated by inequality, leading to higher levels of distrust in democratic institutions-and worse.”

The group claims to be bipartisan and not endorsing a particular candidate but they do signal out a proposal originally submitted by the Democratic Presidential candidate Senator Elizabeth Warren that would raise taxes on those with annual incomes in excess of $50m. She estimates this tax would yield $2.75tn within a decade.

The bottom 99% of Americans pays 7,2% of its income in taxes, compared to 3,2% for the 0,1% of Americans, the letter underscores. In 2011, Warren E. Buffett published an essay pointing to the fact that his personal income tax rate was lower than for any of his employees. A similar essay was written by Nick Hanauer in 2014.

Besides Warren, a number of high-ranking Democrats are calling for income redistribution policies, including New York Congresswoman Alexandria Ocasio Cortez and Vermont Senator Bernie Sanders. President Donald Trump proposed a one-off wealth tax in 1999 to cut the national debt but did not advance this policy since he was elected.