Who was the previous biggest paying sponsor?

Do you know what it was called?

Do you have any examples? I looked at the MCFC sponsor page and none seemed off (other than WeWork).

I could see how some of them might involve ‘laundering’ but that would apply to any club, e.g. overpayment on services for that company whilst receiving sponsorship, but I assume that that’s at least against sponsorship rules, if not illegal, and would apply to any club anyway.