A bench headed by Justice S S Nijjar issued notice to the Centre and the SEBI chairman, directing them to file their replies within four weeks on alleged irregularities in Sinha's appointment.
The bench also impleaded the President's Secretary Omita Paul, who was the advisor of the then finance minister when the decision to appoint Sinha as SEBI chairman was taken by the government.
The bench impleaded her after it was alleged that she had bent rules to facilitate Sinha's appointment as SEBI chairman by bypassing other candidates who had applied for the post.
The bench, however, refused to issue notice to the Centre on plea for CBI inquiry into appointment of Sinha. The court passed the order on a PIL filed by one Arun Kumar Aggarwal, seeking to quash Sinha's appointment.