A government can't decide if something is fungible or not.
The government can limit how you use a specific bill, but that doesn’t make it less fungible, fungibility is about the bill’s equal value, not whether it’s blocked.
Fungibility is an inherent economic property where one unit of a good, like a $10 bill, is interchangeable with another of the same value in a free exchange.
A blacklisted bill might be harder to spend in a regulated system, but in principle, its value remains equal, one $10 bill still represents the same purchasing power as another to anyone willing to accept it.
If a new $10 bill is issued and the old ones lose value, it's not because the government says they're illegal or worthless. It's because the market, meaning people, decide not to accept them at the same value.
Fungibility hinges on market agreement that each $10 bill is interchangeable with another.
If people start treating old bills as less valuable or reject them, that's what breaks fungibility, not the government's decree.
As Mises in 1912 and Hayek in 1976 pointed out, money's fungibility comes from its uniform acceptance in trade, not state control.
This isn't my opinion, this is objectively what fungibility means, regardless of what anybody thinks it should or wants it to mean.
If the government blacklists a bill’s serial number or restricts a digital transaction, it’s imposing an external restriction, not changing the bill’s intrinsic value or equivalence to another $10 bill.
Government actions, like tracking serial numbers or seizing assets, affect how money is used or monitored, but fungibility is about the asset's equal acceptance by other people.
Government singling out certain money doesn't change the money's inherent properties, they are imposing restrictions on those properties, not changing them.
Even with gold, its fungibility as a material (one ounce equals another) holds regardless of whether a coin is stamped or tracked.
If a coin is banned, the gold’s not just worth the same when melted down, it still is of the same economic value.
A banned book is still a book, same as a blacklisted $10 bill is still worth $10 to anyone who'll take it. Fungibility is about the bill's equal value, not government rules, per economic definitions like Investopedia's.
A book isn't fungible because they are unique, not because what the government says or does.
Other non fungible assets like real estate or art, governments don’t make them non fungible; their unique traits do. Money’s fungibility is the opposite, baked into its design as equal units.
From investopedia, fungibility means each unit is substitutable for another of the same kind, focusing on the asset’s nature, not external rules.
Government restrictions affect circulation, not the economic trait of fungibility, as noted in a 2018 ResearchGate paper: Fungibility implies rational indifference to exchanging one unit for another of equal nominal value.
A 2025 Wikipedia update even distinguishes fungibility from liquidity, noting that fungibility is about unit equivalence, not ease of exchange, which further separates it from regulatory control.
FasterCapital’s 2024 piece on fungible assets, which emphasizes money’s role without linking it to government control.
The 2018 ResearchGate paper titled The Identity, Fungibility, and Anonymity of Money for a scholarly take on money’s inherent interchangeability.
These all clarify that fungibility is an economic property, not a government-controlled switch.
The government can limit how you use a specific bill, but that doesn’t make it less fungible, fungibility is about the money’s equal value, not whether it’s blocked.
The ban only affects its legal use, not its identity or value in exchange.
How many dollar bills or digital dollar have you seen that are worth more or less than another digital dollar or dollar bill of the same amount? Answer: None, because they are fungible.
Notable economists have discussed fungibility as an economic property, particularly in the context of money, emphasizing its inherent nature rather than government control.
The term itself, derived from the Latin fungibilis (meaning substitutable), was used in legal texts as early as the 17th century to describe interchangeable goods, like grain or coins, and likely entered economics from there.
And in 18th-century English law, fungibility described goods where one unit is interchangeable with another, such as grain or money. It was often tied to commodities.
In late 19th century legal/economic discussions, such as those in Black’s Law Dictionary (first published 1891), which defines fungible goods as interchangeable, like money or commodities.
Adam Smith in The Wealth of Nations (1776) indirectly touched on fungibility when describing money’s role as a universal medium of exchange, where units are interchangeable.
Carl Menger, in his 1871 book Principles of Economics, further laid the groundwork by discussing how money’s value comes from its uniform acceptance in trade.
In his 1871 Principles of Economics, describes money’s role as a fungible good because each unit is accepted as equivalent, based on its utility in exchange, not state control.
William Stanley Jevons in his 1875 book Money and the Mechanism of Exchange.
He uses the term explicitly when describing money’s properties, noting its fungibility as the quality that makes one unit interchangeable with another, emphasizing its role in trade.
Ludwig von Mises, in his 1912 work The Theory of Money and Credit, describes money’s fungibility as a core trait, where each unit is interchangeable because of its uniform value in exchange, independent of external restrictions.
He specifically to the market’s acceptance, not government authority.
Similarly, Friedrich Hayek, in The Denationalisation of Money from 1976, argues that money’s fungibility stems from its role as a medium of exchange, not from state mandates, even suggesting private currencies can be fungible without government involvement.
Milton Friedman, in his 1960 A Program for Monetary Stability, notes money’s interchangeability as key to its function, separate from government restrictions like capital controls.
Murray Rothbard, in his 1962 book Man, Economy, and State, emphasizes that money’s fungibility comes from its uniform value in trade, a market-driven trait, not something governments can redefine.
He sees it as a natural outcome of people treating units as equal.
And for the Statists out there, even Paul Krugman has touched on fungibility indirectly in his writings on currency, like in his 1999 book The Return of Depression Economics, noting that money’s interchangeability is what makes it function, regardless of regulatory barriers.
None of these economists frame fungibility as government-controlled; they treat it as an intrinsic economic characteristic.
Dictionaries, institutions, financial education websites written by experts, even wikipedia, institutions and economists including those backed by the government universally define money’s fungibility as its inherent interchangeability, and specifically not something governments dictate. It’s about market value, not legal status or any other imposed restraint.