Non-Transferable Token

A non-transferable token is a token locked to the address that holds it - it cannot be sent to anyone else. It is the strongest form of transfer restriction: where most restrictions limit who can receive a token, a non-transferable token blocks transfer entirely. These are sometimes called soulbound tokens, a term popularized for identity and credential use cases.

The point is to represent something that is meant to stay with one holder. Good fits include an on-chain credential or attestation - proof that an address passed KYC or is an accredited investor - a membership or reputation badge, or an identity record. In each case, the value comes precisely from the fact that it cannot be sold or handed to someone else, so it reliably refers to one party.

For real-world assets, non-transferability shows up in two ways. First, as the underlying credential layer: a verified-investor attestation that gates access to a whitelist is far more useful if it cannot be transferred to an unverified buyer. Second, as a temporary state of a security itself - during a mandatory lock-up a token may be fully non-transferable until the period ends, after which normal restricted transfers resume.

Technically, it is usually implemented by having the contract's transfer function always revert (except perhaps for controlled issuance and burning by the issuer). The token can still be minted to a holder and, where lawful, recovered or burned by an authorized agent - it just cannot move holder-to-holder.

An investor should read permanent non-transferability as exactly that: a token designed never to be sold is not a liquid position, and that is by design, not a defect.

Source: Ethereum Improvement Proposals (eips.ethereum.org), as of 2026.