John D. Rockefeller. It happened on Sept. 29, 1916, and newspapers made it a big deal, just as modern media have done with Musk.
The first millionaire and multi-millionaire was John Jacob Astor.
Here is a question where I was too lazy to do all the research and math, so I asked ChatGPT.
In the history of America since the country was founded, who has been the richest American … as a percentage of the country’s economy? (I think Anderson Cooper’s book suggested it was John Jacob Astor, but I have not verified that in any way.)
Here is the answer it gave:

By pure CPI calculation, Rockefeller’s fortune only amounts to $30 billion, but that is deceptive. CPI inflation does not grow nearly as fast as the overall economy, stock market, population, or national wealth. It’s pretty obvious that Rockefeller, with wealth at 1.5% of GDP, was far wealthier than a man with $30 billion today. To illustrate the point, consider the logical extension ad absurdum. Clearly a man with $30 billion when everyone else has nothing is richer than a man with $30 billion when everyone else has $29 billion. Rockefeller is closer to the former, but was still not as rich as Musk. No matter how you do the calculation, Musk comes out on top.
Here are some variations:
(1) Business Insider calculated, “What would a fortune of the same relative economic weight be today?” by using a variety of factors. They calculated that the weight of Rockefeller’s wealth would be equivalent to $499 billion today, still leaving Musk twice as rich.
(2) If you use the gold standard, Rockefeller had enough wealth to buy 43.5 million ounces of gold. That would be worth some $180 billion today. So he was still nowhere near Musk’s league. Musk would be about six times as rich as Rockefeller by that measurement.
(3) Another interesting measurement is the ratio of the wealthiest man to the nearest contender, Musk is now 3.6 times as wealthy as Larry Page, who is in second place. As far as I can tell, none of the historical tycoons ever reached that ratio between them and their nearest rival. Astor made it to 3x. Bill Gates made it to 2.5x at one point. Rockefeller and Vanderbilt were approximately 2x.
No matter how you shake it out, Elon is now the top dog. Elon is not just rich because of inflated dollars. He is the richest American in history. He is at least twice as rich as John D. Rockefeller or JJ Astor ever were. To use an old-fashioned term, he is the ultimate tycoon.
Semi-related:
I was curious about where such a strange word came from.
Also from AI:
The word tycoon comes from the Japanese word taikun (大君), which literally translates to “great lord” or “supreme commander.” Its journey into the English language is a fascinating historical shift:
The Japanese Origin: During the Edo period, Japanese officials used taikun as a diplomatic title for the shōgun (the supreme military dictator) in communications with foreigners. They wanted to convey that the shōgun held the ultimate power in Japan, independent of the emperor.
American Adoption (1850s–1860s): Following trade negotiations in the 1850s, the term made its way back to the United States. During the Civil War, aides to President Abraham Lincoln adopted it as an affectionate nickname to highlight his supreme leadership authority.
Modern Meaning: By the 1920s, the term evolved to describe exceptionally wealthy, powerful, and influential leaders in business and industry










