Charles Wang
Technically, we’re cheating by including the late Wang on this list. But the former Islanders owner was one of the worst in sports history. He made mistakes that money couldn’t hide. However, ironically, his biggest mistake was trying to hide money because he misreported the franchise’s cable earnings (via ESPN).

Some people give Wang credit because he kept the team on Long Island. However, the team remained in rebuilding mode throughout his reign and made no progress on the ice. They made terrible recruitment decisions and he failed to fire GM Mike Milbury. He made mistakes that stalled the franchise’s development.