Complex sentence: The school was ranked as the 67th best business school in the FT ranking in 2011, Its ranking declined after the formation of France Business School, but after ESC Clermont gained its independence in 2015, the school is back in the ranking list.
Split into simpler sentences: The school was ranked as the 67th best business school in the FT ranking in 2011, but its ranking declined after the formation of France Business School. After ESC Clermont gained its dependence in 2015, the school is back in the ranking list.