"Perpetual bond" (also called perpetual bond, perpetual loan, or in slang "perps") is a bond that has no maturity date and thus is not redeemed. The issuer only pays interest, with no obligation to ever repay the principal.

Because these bonds have no final maturity, it is difficult to calculate an exact effective return. A well-known example in the Netherlands is the ledger loans of the Dutch state, which still pay interest.

In practice, many loans labeled as "perpetual" are eventually repaid by the issuing institution. This occurs at a time of the institution's choosing, which is called "calling" in jargon. Perpetual bonds are primarily issued by financial institutions because, because of their long maturity, they are considered risk assets.