A perpetual security a security (financial security) that is issued by a company without any obligation to redeem it from the holders/ investors. Such a long-term debt instrument only provides a steady income stream (stated coupon) to its holders, virtually without being subject to an expiration date. In that sense, it is very similar to equity (equity securities), and ranks fairly low in terms of priority. The issuer may, however, possess a call option whereby it can choose to redeem the security at a certain point in time.

In terms of accounting classification, perpetual securities are classified as equity. These securities may take the form of convertibles– i.e., those that can be converted to stocks, and non-convertibles (those that cannot). Further decomposing convertible perpetual securities, there are such securities carrying a fixed price (fixed price convertible perpetual securities) or others that have floating price (floating price convertible perpetual securities).

The main examples of perpetual securities are:

• Perpetual bonds/ perps (consol bonds).
• Perpetual preferred share (perpetual preferred).
• Perpetual debentures.