vested interest

Meanings

1. An indefeasible right or title, distinguished from a contingent interest, which could be defeated (i.e. cease) if a certain event occurred.
2. A fixed right granted to an employee, especially under a pension plan.
3. A stake, often financial, in a particular outcome.
4. A group of people or organizations with such a stake, especially those that seek to control an existing system or activity from which they derive benefit.
5. An exceptionally strong interest in protecting or promoting something to one's own advantage.

Etymology

Popularized in sociology by Thorstein Veblen, The Vested Interests and the Common Man (1919). But used earlier, e.g. by Winston Churchill: * 1899, Winston Churchill, The River War, an Account of the Reconquest of the Sudan, page 15: The name of the General was a sufficient guarantee that the slave trade was being earnestly attacked. The Khedive would gladly have stopped at the guarantee, and satisfied the world without disturbing 'vested interests.' But...