Insiders, who have been chosen as CEOs of companies like Mukesh Ambani of Reliance Industries and Steve Jobs of Apple, have fared better than those who have been brought in from outside, says a survey.

Mukesh Ambani, who heads India's most valuable company Reliance Industries, has been ranked among top five best performing CEOs in the world by the prestigious Harvard Business Review.

In the midst of the debate over what salaries CEOs should be taking home, Prime Minister Manmohan Singh on Sunday ruled out any move to impose restrictions on their remuneration, saying it is best left to boards of companies.

US companies remain generous with the perks they give to CEOs, including some that are unfathomable to the average American worker: chauffeured cars, bodyguards, club memberships and free travel in company jets.