The Mexican government has launched a probe into the appointment of the former Mexican treasury secretary to the HSBC board amid concerns that it has violated conflict of interest rules.
Mr Gil Diaz was charged with supervising the HSBC's Mexican arm as part of his ministerial post and his decision to join the board of the London-based group has caused consternation in his home country.
The European banking giant claims that it is not aware of any legal reason why Mr Gil Diaz cannot join the company as a non-executive director.
Prompted by a complaint from opposition politician Carlos Reyes Gamiz, the probe by the Mexican Public Administration Department will examine whether there is a conflict of interest in the former treasury secretary, who held office between 2000 and 2006, taking up his appointment.
According to Mr Gil Diaz, he has been appointed as an independent director and will not be an HSBC employee.