Students from top tier universities have higher chances of getting jobs in prestigious and well known companies. Employers are usually inclined to hire those from top universities for the benefit of the company as they see these graduates as great additions to help it grow due to the reputation they hold.
Now, why do these companies have a bias towards hiring students from top universities? For the most part, top universities are not easy to get into due to their higher requirements. Therefore, top companies are aware that top students go to top universities which are breeding grounds for outstanding students with deep rooted connections.
In this way, students from top universities have an advantage over better employment opportunities that most other universities do not have.