As the auto world makes sense of Carlos Ghosn's sudden fall from grace at Nissan Motor Co., one thing is clear: The legendary executive was a victim of dismal corporate governance at the company he sat atop for decades.

Allegations against Ghosn include under-reporting his income in securities filings and making personal use of company assets. The deposed chairman denies wrongdoing in connection with the allegations, public broadcaster NHK reported on Sunday.

Unlike most scandals at Japanese companies in recent years, this one centers on personal rather than corporate misconduct. Several theories have been floated on the reasons for Ghosn's downfall: an internal coup, axes to grind, too much power concentrated in one person. But how does a board blame the chairman for misleading the company about his pay? Why are the other directors or auditors not held responsible for incorrect filings?