Why do I have a different percentage of genetic matches than my sibling?

The chromosomes of both the mother and the father, before being passed on to the offspring, undergo a random exchange of genetic information between them. Therefore, each child inherits the chromosome of his/her parents with small different changes. For this reason, the percentage of matches can vary between siblings.

The only exception is twins. Since the genetic similarity in twins is over 99.9%, in that situation, the genetic matches should be practically the same.