C. Rangarajan, Chairman of The Prime Minister's Economic Advisory Council
A former central bank governor, Rangarajan is not shy about airing his views on monetary policy and his statements are seen as reflecting the official thinking of Singh's administration.
His remarks, including strongly worded statements urging the central bank not to raise rates, are taken seriously by the financial markets.
Another member of the old guard, the 78-year-old Rangarajan sits at the head of the prime minister's economic advisory council, which provides guidance Singh but has no direct link to policymaking.
Rangarajan is viewed by many market participants as wielding clout above his official rank.