There are two things that are clear as you analyze the financial ledgers of Big Ten football programs:
1) Every school has different accounting methods, which leads to a fairly subjective view of whether a football program was in the black.
2) The football programs that spend the most money tend to be the ones that have the most on-field success.
According to an NJ Advance Media review of the 13 Big Ten schools whose 2017 Fiscal Year reports are publicly available (Northwestern, as a private school, wasn’t available), the top-7 programs in spending each won 8 or more games during the 2016 season.