Nadler and Schiff are expected to become chairmen of their committees in the next Congress.

What her sister won't discuss is why so many of her male corporate contemporaries have become chairmen and she has not.

The review by Mr Derek Higgs, which comes into force next month, recommends that chief executives should not become chairmen of the same company.

He said the measures would include a ban on cross-directorships and on chief executives becoming chairmen, as well as creating a Central Bank commission.