The Koch Brothers are industrialists and political activists who, among other goals, want to rewrite the U.S. Constitution — and if money talks, the Founding Fathers better start listening. Charles Koch and David Koch have a combined net worth of $96 billion, says Forbes — making them a richer entity than Bill Gates.

Koch Industries, based in Wichita, Kansas, was founded in 1940 by Fred Koch and partners. It began as a crude oil refinery and over the years, it turned into a private company involved in manufacturing, trading and investing that has some form of control over most business categories.

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Fred Koch and Mary Robinson Koch had four sons: Frederick Koch, Charles Koch, David Koch and William Koch. Charles Koch became president of Koch Industries in 1968, following his father’s death the previous year. He and his brother David bought out their brothers, Frederick and William, for full control of the company in 1983.

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Signs of the Koch Brothers held at a rally where protesters demand the LA Times not be sold to the Koch Brothers on May 23, 2013 in Beverly Hills, California. JOE KLAMAR/AFP/Getty Images

Forbes listed Koch Industries as America’s second largest private company in 2016. The company generated $100 billion that year, employing more than 100,000 people worldwide in over 50 countries. Each brother is worth $48 billion; their wealth combined is greater than that of Gates, the co-founder of Microsoft, whose net worth is $89.1 billion. To put that in perspective, Gates has been at the top of Forbes list of world billionaires for 18 out of the past 23 years.

Koch Industries has expanded by buying other companies to increase its revenue. The Koch brothers have acquired Invista, Georgia-Pacific, Flint Halls Resources, Koch Pipeline, Koch Fertilizer and Koch Minerals, among others. Koch has focused on owning companies focused in core industries like manufacturing, refining and distribution of petroleum and minerals. However, they also acquired companies like Brawny paper towels and Dixie cups.

“At first glance, Koch companies may look curiously unrelated. After all, they stretch from the fibers of fashion to the rugged world of ranching,” the Koch Industries website reads. “When you look deeper, there’s a common thread that ties them together. It’s a desire to keep improving the products that meet your basic needs every single day.”

Over the years, the Koch brothers have involved themselves in politics, donating large amounts of money to conservative causes. David Koch ran as the Libertarian Party’s vice-presidential candidate in 1980, but since then, both brothers have supported mostly Republican candidates. Koch Industries has always placed emphasis on free market principles, and through donations and public support, the Koch brothers made their mark in American politics. Two of their political organizations, Americans for Prosperity and Freedom Partners, embody their goal— both organizations advocate for less government regulation and lower taxes.

They have vehemently opposed climate change legislation, donating money to support climate change skeptics. They expressed their dislike of then-presidential candidate Donald Trump during the 2016 election, comparing the choice between Trump and Democratic nominee Hillary Clinton to choosing between a heart attack or cancer.

Still, the brothers are backers of Vice President Mike Pence and now have allies throughout the White House and the Trump administration.

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Former Senate Majority Leader Harry Reid (D-Nevada) is no fan.

“These two brothers are trying to buy America,” he said on the Senate floor in February 2014, responding to Koch-funded anti-Obamacare ads. “I don’t believe America is for sale.”