When she joined in 2005, the enforcement division employed about 300 staff and had levied fines of only 43.8 million during the previous three years.

As with the original inquiry, it will be conducted by its enforcement division.

But depending on what it finds, the investigation could be passed on to the regulator's powerful enforcement division.

The recruitment of more highly paid lawyers and investigators to the enforcement division has surprised industry insiders because it comes against an uncertain backdrop for the department.

He has recently added a new law enforcement division to his department.