Independent: Even by the standards of the super-rich, Charles and David Koch are extraordinarily wealthy. Together they own most of Koch Industries, one of the largest private conglomerates in America with annual revenues of around $100bn (62.5bn), and interests as diverse as energy, petrochemicals, pulp and paper.
The two brothers share a similar political outlook. They are right-wing libertarians who believe in minimal regulation of industry, smaller government, lower corporate taxes and less generous social...