On the MAT application, 'MI' stands for Management Institute. A 'Participating Institute' is any B-school that has officially registered with AIMA to receive candidate scores for the current session. During registration, you can select up to 5 MIs (or 7 if appearing for both PBT+CBT) for free score reporting. If you wish to apply to more than the free limit, you must pay an additional fee of ₹118 per institute. It is important to check the AIMA website for the updated list of participating MIs before selecting, as some colleges may skip a specific session.