History of the Rothschild family and is it true that their combined net worth is 500+ trillion USD

Not unless the Rothschild family owns everything on Earth.

You see, the total value of all real estate on Earth is ~$210 trillion (as of 2015). The total wealth of the world (sum of money with everyone) is around $241 trillion, bringing the total to $450 trillion. Yes, it does exclude a lot of natural resources, but I am pretty sure the Rothschilds do not own the forests and rivers and oceans of the world.

Snopes debunked the said myth

Claim: The Rothschild Family owns 80% of the world's wealth, with a net worth of $500 trillion.

FALSE

Origin:

The Rothschild family is rich, but claims that they have a net worth of $500 trillion and own 80% of the world's wealth are grossly exaggerated. Images reflecting an old rumor about the Rothschild Family’s unimaginable accumulated global wealth hold that the Rothschilds are worth $500 trillion and hold more than 80% of the world’s total wealth:

While the Rothschilds are indeed very wealthy, claims about their net worth such as the ones displayed above are grossly exaggerated. Conspiracy theories concerning the Rothschild family date back to the 18th century, and the family’s wealth was largely responsible for the anti-semitic belief that “Jews control the world’s money supply.” The Rothschilds are frequently associated with theories about the Illuminati, the New World Order, and other dark money groups that supposedly pull the strings of world governments, and the Rothschilds have been blamed for everything from starting wars for personal gain to funding the Holocaust to assassinating U.S. presidents.

Skeptoid delved into the Rothschild family history in 2012, noting that:

The greatest of these financial adepts was Mayer Amschel Rothschild, born in 1744 in a Jewish slum of Frankfurt. Not much is known about his early life, as he was one of tens of thousands of marginalized, outcast families. But once he came of age he became an apprentice at a small bank in Hamburg, where he learned the trade. Returning to Frankfurt at the age of 19, he offered his own banking services in a modest way, beginning with the trading of rare coins and related investments. He was energetic, clever, and most of all he was charismatic. And he was smart, seeking out wealthy clientele, and associating with nobility whenever he could. By the age of 40, he had consolidated his most important business contact: the Landgrave William, the Elector of Hesse, one of only a tiny number of nobles empowered to elect the Holy Roman Emperor. When William was younger, he had engaged in the trading of rare coins with Mayer’s father, and so the two had always known one another. When William inherited his own father’s massive fortune, his friendship with Mayer Rothschild gave Mayer the ability to begin conducting larger international transactions.

This was the point at which the Rothschild name became first involved with the manipulation of money behind the scenes of wars. Mayer was a firm believer in the family business, and insisted on using his own sons — by then he had five — as his business partners. What he did next became the model for many powerful Jewish financiers who followed: He installed each of his five sons as his agents in the five major financial centers of Europe: the eldest Amschel Mayer Rothschild in Frankfurt, Salomon Mayer Rothschild in Vienna, Nathan Mayer Rothschild in London, Calmann Mayer Rothschild in Naples, and the youngest Jakob Mayer Rothschild in Paris.

Although the Rothschild family has amassed great wealth since the 1700s, claims that they have a net worth of $500 trillion or that they own 80% of the world’s wealth are problematic.

For one, the world’s total wealth was estimated as of 2015 to be only $250 trillion, half of what the Rothchilds alone are claimed to possess:

Global wealth reached 250 trillion US dollars in 2015, slightly less than a year earlier, due to adverse exchange rate movements. The underlying wealth trends do, however, generally remain positive, according to the Credit Suisse Research Institute’s annual “Global Wealth Report.”

Also, the Rothschilds began acquiring their wealth in the 1700s, and since then the family has spawned hundreds of descendants, so there is no longer any centralized Rothschild family wealth. The closest thing to a “Rothschild Family” business in 2016 is the Rothschild Group, a multinational investment banking company, but that firm does not in itself generate nearly enough income to back up claims about the family’s wealth. In 2015, the Rothschild Group’s annual revenue was approximately $500 million. In comparison, the world’s largest company, Walmart, has an annual revenue of nearly $500 billion.

It should also be noted that only one member of the Rothschild family is included among Forbes’ 2015 list of the world’s billionaires: Benjamin de Rothschild, who was ranked at number #1121 with a net worth of $1.61 billion.

While the Rothschild family certainly was one of the world’s most significant financial powers in centuries past, they no longer wield the same sort of influence over global affairs.