Tata Consultancy Services Limited has entrusted Sivakumar Viswanathan, a veteran of about 30 years, as the new head of the Resource Management Group, or RMG. Viswanathan is a trusted lieutenant of new chief executive officer (CEO) K. Krithivasan and is based in Chennai, home to about a fifth of TCS's 614,795 employees. The former global head of the recruitment arm E.S. Chakravarthy has been sent on leave after a whistleblower blew the lid on unethical practices at the hiring of contract workers, alleging in an email sent to the CEO and the chief operating officer that many executives had been taking commissions from staffing firms for years.