Definition
A digital commodity is generally an onchain asset whose value comes from open-market supply and demand rather than the ongoing work of a central issuer.
Fungibility, transferability and decentralization make an asset more comparable to a commodity than to a company share.
Commodity versus security
A security usually represents an investment where buyers expect profit from the efforts of a company or promoter.
The distinction affects disclosure, registration, venue access and which regulator has primary authority.
The U.S. agencies
The SEC focuses on securities markets and investor protection, while the CFTC primarily regulates commodity derivatives.
The spot-market boundary is more limited and is one reason proposed market-structure legislation remains important.
Examples and uncertainty
Bitcoin is the clearest example of an asset commonly treated as a digital commodity, while other assets can require more nuanced analysis.
Classification can depend on the asset, the transaction and the jurisdiction, so a label should not be treated as a universal legal conclusion.