U K Sinha is set to become the second-longest serving Sebi chairman after the finance ministry extended his term by two years. C B Bhave, M Damodaran and G N Bajpai, the three preceding him, all had three-year terms. D R Mehta, Bajpai's predecessor, has had the longest term of 7 years as chairman. Sinha has served as chairman under two finance ministers, Pranab Mukerjee and P Chidambaram