Why you need diversification.
Presenting 4 companies which used to be industry leaders at some point of time.
They were so called "Quality" and "too big to fail" companies.
Fundamentals and Price is visible to all now.
As a retail investor you can never fully understand the intentions and under the carpet issues of promoters and managers.
This is why you need to diversify.
Concentrated portfolio is a double edged sword.
If you are not experienced enough it can cut you deep.