The possessive suffix is an feature unique to Finno-Ugric languages. It has the same function as possessive pronouns do when indicating ownership. For example, Finnish has this set of possessive suffixes:
Formal
English
taloni
my house
talosi
your (sg) house
talonsa
his house
talomme
our house
talonne
your (pl) house
talonsa
their house
It is optional, not mandatory as in English, to use pronouns in the genitive with these words, e.g. minun taloni means "my house" with or without the minun ("I's").