A Swiss octogenarian billionaire has donated tens of millions of dollars to Democratic politicians and progressive causes in “dark money” contributions — and Hansjörg Wyss is likely funneling millions more to influence midterm elections in November, sources say.

One Virginia-based think tank estimates that, since 2016, nonprofits linked to Wyss have funneled more than $253 million to Democratic candidates and related causes, such as voter registration initiatives that benefit the party and efforts to impeach former President Donald Trump, through a dizzying array of related nonprofits.

“The foreign dark money revolving door is at it again, this time with their eyes set on the midterms,” said Caitlin Sutherland, executive director of the conservative Americans for Public Trust. “Wyss has already funneled hundreds of millionsthrough his nonprofits to liberal groups that influence our elections, and now those very same groups are poised to engage in every policy and political fight all the way until November.”

Sutherland said the total amount allegedly funneled by Wyss’ nonprofits to Democratic advocacy groups is likely “much, much higher,” but estimates are difficult to track as cash is often transferred through nonprofits that have more than a year’s lag time to publicly report their donations to the IRS.

Wyss, 86, is not a US citizen or permanent resident, and cannot directly or even indirectly make contributions to federal political candidates, according to a 2021 complaint to the Federal Election Commission filed by Americans for Public Trust. The group is suing the FEC in district court in Washington, DC, alleging that the federal agency has been slow to act on its 2021 complaint against Wyss.

Worth more than $5 billion, Wyss resides in the US under an E-2 investor visa, according to court papers.

“We know that for years Wyss has funneled millions of dollars to left-wing nonprofits that boost Democratic turnout and provide partisan campaign strategy,” said Hayden Ludwig, a senior investigative researcher at Capital Research Center, a Washington, DC-based conservative think tank that studies philanthropy and nonprofits.