Today in History—September 29: John D. Rockefeller Becomes the World’s First Billionaire

On this day in 1916, newspapers reported that John D. Rockefeller had become the world’s first billionaire.

But had he?

A sharp rise in the value of Rockefeller’s oil-company holdings the previous day had apparently pushed his fortune past $1 billion. Newspapers had taken to tracking his wealth almost like a baseball box score, but there was no precise tally. Reporters had to estimate what he owned and what those holdings were worth, making his billion-dollar fortune something of an educated guess.

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Rockefeller came by the oil business in a roundabout way. His father, William (“Big Bill”) Rockefeller, was a traveling physician and snake-oil salesman. Young John turned his attention to another kind of oil: the rapidly expanding petroleum industry. He built a refinery near Cleveland in 1863, and within the next two years it had become the largest in the area.

Then Rockefeller started buying. He and several associates incorporated Standard Oil in 1870, and within two years the company controlled nearly all of Cleveland’s refineries. That gave Standard clout with the railroads, which it used to negotiate favorable shipping rates. It bought pipelines, terminals, and competing refineries, and by 1882 Standard Oil had a near monopoly on the U.S. oil business.

Standard Oil’s dominance eventually drew the attention of lawmakers and the courts. When Ohio ordered Standard Oil’s trust dissolved in 1892, Rockefeller shifted its properties into affiliated companies that remained under common control and later reunited them under a New Jersey holding company. Finally, in 1911 the U.S. Supreme Court ruled that Standard Oil violated federal antitrust law and ordered it broken up.

And Rockefeller got richer.

He owned about a quarter of Standard Oil, and the breakup didn’t take his ownership away. Instead, it made him a major shareholder in 34 independent—and increasingly valuable—companies. Five years after the government dismantled his monopoly, newspapers were calling him the world’s first billionaire.

Whether Rockefeller actually reached the $1 billion milestone in September 1916 remains debatable. But it stuck. And whatever his fortune ultimately reached, Rockefeller gave away more than $500 million during his lifetime, much of it to education, medical research, and public health.

The next three-zero milestone took 110 years. In June 2026 Elon Musk became the world’s first trillionaire when the SpaceX initial public offering sent the estimated value of his holdings soaring.