You want to go to the big 4 with the best practice in the area that you specialize in.
However, they cannot cover every circumstance.
Usually, these firms get ranked based on their revenues during a year.
Starting in the mid-1900s, there was a series of mergers which ultimately created Deloitte Touche Tohmatsu Limited, the Deloitte accountancy we have today.
Working for one of these organisations can help you improve your skills and establish yourself as a skilled accounting professional.
Some of the universities that have these programs are Columbia Business School and Duke University.