A stake in an entity is partial ownership or a position that entitles its holder to gain when the entity achieves good results. In a specific context, a stake is the amount of stock (or equity holdings) an investor owns/ holds in an entity, representing the percentage of the stock or holdings to the overall number of stocks or amount of equity (on a proportional basis).

An interest is the equity ownership of a person (legal or natural) in an entity or specific assets of an entity, expressed in absolute monetary terms or as a percentage. For example, an investing entity may own 20,000 shares of an investee entity (with a base of 100,000 shares outstanding), in which case the investing entity has an equity interest or ownership interest of 20% (in the investee).

In view of the above definitions, stake and interest almost imply the same thing. But for a stake, it may extend to denote an amount of money a person (or an entity) stands to lose when efforts or a venture/ undertaking fails to achieve desired results or doesn’t perform as per set plans. In this context, it may also imply the risk of loss (of money invested or endeavors, etc.)

In short, stake is more inclusive than interest, as it [stake] has many meanings including money invested in a business or an ownership share or control (as a percentage, e.g., 51% stake) in a business or non-business, etc., or money risked for a certain purpose.