koch brothers oil refinery 2x1David and Charles Koch are two of the richest people on earth.iStock; Mark Lennihan/AP Images; Hoover Institution/YouTube; Samantha Lee/Business Insider

  • The Koch brothers are two of the richest men in the world.
  • Charles and David Koch each have a net worth of $53.7 billion, according to Forbes.
  • Their fortunes come from their 42% stakes in the Koch family business: Koch Industries.
  • Charles is currently the company’s president and CEO, while David just announced that he was retiring from the firm.

The Koch brothers are two of the richest people on planet earth.

Charles and David Koch tied for eighth on Forbes’ 2018 list of the wealthiest billionaires in the world.

And they’re also two of the most controversial billionaires out there, at least when it comes to their political contributions. Jane Mayer’s 2015 book “Dark Money” outlined how the two Kansas natives reportedly used their fortunes to forge a formidable web of political influence, with the intent of promoting their libertarian values.

Still, that hasn’t stopped the Kochs from clashing with figures on the right, mostly notably US president Donald Trump. The two brothers have spoken out against Trump’s tariffs.

So how did the Kochs come to amass so much wealth and wield such influence in the first place? The answer lies within the history of their family business: Koch Industries.

Here’s a look at how the brothers became billionaires in the first place.