Lower oil prices, however, have varying implications for upstream and downstream businesses. For instance, oil refiners, part of downstream operations, stand to benefit from cheaper crude prices given lower input costs.
Another major shareholder in Koch Industries, Elaine Marshall saw her net worth increase by 6 percent to $8.3 billion, ranking in sixth place.
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Claiming the fourth spot is Richard Kinder of pipeline giant Kinder Morgan, who has also been well insulated from the oil rout, with his fortune growing a whopping 23 percent over the past seven months to $11.3.
Shares of Kinder Morgan, which make up the bulk of his wealth, have risen 25 percent since June amid restructuring efforts to lower the company's cost of capital. The bulk of its earnings are through fixed contracts with customers that transport fuel on its pipelines.
The biggest loser
Of course, not all have been able to hold on to their wealth in the face of oil's collapse.
Harold Hamm lost 50 percent or over $9 billion of his personal fortune since June, claiming the title of the biggest loser. His current net worth now stands at $9.3 billion – ranking him in the fifth place.
The CEO of Continental Resources has not only been burnt by the fall in oil prices but also a protracted divorce battle with his wife, during which he gave her a $975 million settlement check, according to Wealth-X.
Sisters Milane Frantz, Randa Williams, Dannine Avara, heirs to their late father Dan Duncan's energy pipeline empire, each saw their wealth decrease by 11 percent to $5.5 billion, placing them in eight, ninth and tenth spot in the rankings. Duncan is the co-founder Enterprise Products Partners, which specializes in onshore and offshore pipelines and storage terminals.