Comptroller and Auditor General Vinod Rai - who quit offi ce on May 22 - is the fi rst of four high-profi le regulators who retire in the next 12 months. The highlights of their tenures and the challenges their successors will face:

Vinod Rai, Comptroller & Auditor General (CAG) of India
VINOD RAIComptroller & Auditor General (CAG) of India
TOOK CHARGE IN December, 2007
RETIRED IN May 2013
HIGHLIGHTSA number of his audits rocked the nation:
Estimated the loss from the 2G spectrum scam at Rs 1.76 lakh crore
Estimated the total profi t for benefi ciaries in the coal blocks allocation scam at Rs 1.86 lakh crore
Other audits exposed the Commonwealth Games scam, the Noida Authority scam, MGNREGA irregularities
SUCCESSOR'S CHALLENGEAudit of AgustaWestland helicopter purchase, since the new CAG Shashi Kant Sharma, as defence secretary earlier, was among those who authorised it
Tackling government's increasing hostility to CAG

U.K. Sinha, Chairman, Securities & Exchange Board (SEBI)
U.K. SINHAChairman, Securities & Exchange Board (SEBI)
TOOK CHARGE IN February 2011
TO RETIRE IN February 2014
HIGHLIGHTSPenalised an RIL subsidiary Rs 11 crore in an insider trading case
Directed two Sahara Group companies to refund close to Rs 24,000 crore to investors
Launched Safety Net Mechanism to protect retail investors' interests in IPOs
Tightened the takeover code
SUCCESSOR'S CHALLENGESTo carry forward initiatives taken by Sinha, especially those to boost participation of retail investors and SMEs in the capital market
Do something about some of the regional stock exchanges where little trading takes place

D. Subbarao, Governor, Reserve Bank of India (RBI)
D. SUBBARAOGovernor, Reserve Bank of India (RBI
TOOK CHARGE IN September 2008
TO RETIRE IN September 2013
HIGHLIGHTSTook charge just as the global economic crisis struck. Brought down interest rates to stimulate growth
As inflation mounted, raised rates and thereafter stuck to them, despite the fi nance ministry's displeasure
As inflation fell, began easing rates again
SUCCESSOR'S CHALLENGESArresting the renewed fall of the rupee against the US dollar
New banking licences are on the anvil. Rolling them out will pose multiple challenges
Ensuring inflation remains at tolerably low levels

Pramod Deo, Chairman, Central Electricity Regulatory Authority (CERC)
PRAMOD DEOChairman, Central Electricity Regulatory Authority (CERC)
TOOK CHARGE IN June 2008
TO RETIRE IN June 2013
HIGHLIGHTSFined states for drawing more power from the national grid than they were entitled to
Compensated Adani Power and Tata Power for losses incurred on coal imports due to changes in Indonesian laws
Directed state regulators to play a more proactive role in power tariff revisions
SUCCESSOR'S CHALLENGESFind ways of enforcing the commission's orders more strictly
Oversee 'open access' and pave the way for a free market in power