Richest person (ever) – adjusted for inflation

The richest individual in history when adjusted for inflation is the American businessman John D. Rockefeller. At the peak of his financial success in 1913, Rockefeller's net worth was $900 million, equal to $631 billion in 2024, although the exact figure depends on the methodology used. Rockefeller made his fortune in the oil industry, establishing Standard Oil Incorporated, which had a near monopoly on oil refining and distribution in the United States during the late 19th and early 20th centuries.

John Davison Rockefeller was born in Richford, a small town in upstate New York, on 8 July 1839. His father was a traveling salesman who sold dubious elixirs and was rarely home. Rockefeller was an earnest, studious youth who formed an ambition early on that he would one day earn $100,000 and live to the age of 100. He studied bookkeeping at a local college and was apprenticed in Cleveland, Ohio, as a book-keeper and debt collection agent.

He started his first business in 1859, trading commodities as a founding partner in the firm Clark, Gardner & Company. In their first year of business, the company made $17,000 in profit (equal to $643,000 by Consumer Price Index inflation, or $8 million relative to wage inflation), and business boomed during the American Civil War, when shortages of goods and high demand from the US Army pushed up prices. Rockefeller donated large sums of money to the Union cause, but avoided conscription.

In 1863, Rockefeller steered Clark, Gardner & Company into the oil business, buying into a new refinery that was designed to operate more efficiently than its rivals. Following the success of this initial venture, in 1867, Rockefeller went into business with financier Henry Flagler and refinery chemist Samuel Andrews, establishing the company that would develop into Standard Oil – Rockefeller, Andrews & Flagler.

Over the course of the 1870s, Rockefeller progressively brought more and more of the US oil industry under his control, either through acquisitions or by bringing rivals in as partners in a cartel called the Standard Oil Trust. By 1879 Standard Oil was responsible for 90% of all oil refining in the United States, and Rockefeller himself had a net worth of $1 million (CPI value of $31,500,000, relative income value of $418,000,000).

As oil became an increasingly essential part of the American economy, politicians and the public turned on Rockefeller and his monopolistic and aggressive business strategies – even though he had largely stepped back from the day-to-day running of Standard Oil in the 1890s. He was widely vilified and subject to various court orders in the 1900s, and in 1911 the government ordered that the Standard Oil Trust be broken up.

In the 1910s and early 1920s, Rockefeller transferred most of his wealth to his children and to the Rockefeller Foundation, a charitable trust. He retained a comparatively small fortune of around $26 m (CPI value of $474,000,000, relative income value of $1.7 bn).

Rockefeller died on 23 May 1937, 2 years 46 days short of his goal of living to 100.

There are several possible ways of calculating inflation adjusted figures. The type of inflation adjustment used here is called "economic share", which is the most appropriate for sums of money as large as this. This calculates Rockefeller's wealth relative to the size of the US economy at the time. Someone who controlled an equivalent share of the US economy today would have a net worth of $631 bn. Calculated relative to the average wage of the time, it works out to $163 bn, and calculated relative to the cost of goods (CPI inflation) it is $28 bn.