What is the list of famous case studies taught at IIM Ahmedabad?

It is tough to list cases over different subjects as there is a huge number of cases available. It is very doubtful that the same cases will remain popular always. It completely depends upon the faculty who decides to choose the cases for explaining a concept.

Case-studies:

• The faculty are generally suggested to use cases within the last five to ten years. This is essential for maintaining the currency of the subject. 
• For instance, a course on e-commerce taught with a case developed in the early years of the internet will not be relatable for the students. As a lot has changed in the start-up domain. Currently, a case on Ola will make a lot more sense to the students than how the HDFC Bank introduced internet banking. 
• For an executive program at IIM, one of my teachers chose a case on Yahoo immediately after Marissa Mayer took over and asked the students to design a strategy for Yahoo. As the conclusions in Yahoo unfolded it made a lot more sense to the students to compare their own perspective with what Meyer did.

One of my friends' field was Information Technology. Some of the cases, he studies during his diploma are as follows. 

• ERP implementation at CISCO. 
• E-commerce at Dell.

The cases developed by IIMA are still the Harvard cases which are more popular at IIMA. There are several cases available from Stanford, Columbia, and some Asian business schools as well.