SIMSREE - Sydenham Institute of Management Studies Research and Entrepreneurship Education

Admission to a particular program or institution depends on several factors besides your MAT score, such as your academic background, work experience, and other qualifications. Percentile and composite scores are just one aspect of the selection process.
However, based on the information you have provided, scoring 86.18 percentile and a composite score of 658 in May MAT is a good achievement. It indicates that you have performed better than 86.18% of the candidates who appeared for the exam.
To determine your chances of admission, you should check the eligibility criteria and selection process of the institution or program you are interested in. You can also refer to the previous year's cutoffs to get an idea of the minimum score required for admission.
It's also important to keep in mind that admission is a competitive process, and there may be other factors that can influence the final decision. So, it's essential to prepare well for the selection process and present your application in the best possible way.