There are multiple definitions - click on the translation that matches your context.

Anwartschaft

Substantiv

partial

vested interest

noun

Definitions of vested interest

English

a right to have or to use something now or in the future

If Texas can reduce the husband's income tax by creating in his wife a 'vested' interest in half his salary and other income, I fail to see why its neighbor, Oklahoma, may not do the same thing.

English

a special reason for wanting something to happen in a particular way, because you could get an advantage from it

He's got a vested interest in the future of the club given the funds he's got committed to it.