Four listed companies announced on Friday that their independent director Song Chang is under investigation by the China Securities Regulatory Commission for suspected insider trading and short-swing trading.

Song is a professor at Renmin University of China, who has been called "the busiest independent director" by the media, because he has been an independent director of more than 10 listed companies in the past.

It is not uncommon for scholars who are the independent directors of listed companies to violate regulations.

It shows independent directors, who are supposed to "take no position other than as a board director and have no relationship with the company or its major shareholders that may affect independent and objective decision-making" are not always independent and fail to perform their legal obligations. Some independent directors are only nominal posts in order to meet the regulatory requirement, and those in the position fail to play their intended role of improving corporate governance, protecting the interests of small and medium shareholders and enhancing transparency in listed companies.

Yet compared to ordinary investors, independent directors have more access to inside information. The authorities should be vigilant against rent-seeking by independent directors, and universities should be aware that some scholars form an interest community with the listed companies, which may undermine their interests.