Fungibility

What Is Fungibility?

Fungibility describes how readily one unit of something can be exchanged for another identical unit without either party caring which one they receive. A twenty-dollar bill is fungible because any twenty-dollar bill is worth exactly as much as any other. A house is not, since each one has its own location, size and condition. Shares of the same class of common stock are generally treated as fungible, because each share carries the same rights as the next, so a broker can deliver any identical share to settle a trade.

How Fungibility Works in Markets

Fungibility is what allows standardized markets to function. A futures contract traded on an exchange has fixed size, quality and delivery terms, so every contract of the same type can be traded, offset and settled in the same way. Fungible securities can be held in pooled accounts and matched through a clearing house rather than tracked as individual objects. This standardization supports liquidity, because buyers and sellers do not need to evaluate each unit separately.

Fungibility and Record-Keeping

Fungible in the market does not always mean identical for accounting. An investor who buys the same stock at several different prices owns shares with different cost basis values, and those differences matter for taxes when only some of the shares are sold. Money works similarly: cash is fungible, which is why funds held for a specific purpose, such as client money held in trust, are usually kept in separate accounts so they are not mixed with other funds.

Advantages and Limits

Fungibility keeps prices easy to compare and lowers the effort needed to trade. Non-fungible assets, such as non-fungible tokens, rare artwork or individual properties, must each be valued on their own features, which generally makes them harder to price and trade quickly. Fungibility is a property of the asset, not a guarantee of value: two fungible units can still lose value together.