SUZLON chief operating officer (COO) Sumant Sinha,who is widely credited for the companys recent refinancing of an overseas bond issue,has put in his papers.While Mr Sinha wasnt available for comment,sources said that an announcement on this could likely be made on Saturday,when the board meets to approve the annual earnings. If Mr Sinhas resignation is accepted,it would mark an end to a two-year period when the wind energy company took aggressive measures to improve its finances.Suzlon,the worlds fifth largest wind turbine maker,saw sales slow down as the liquidity crisis eroded demand in Europe,prompting the Pune-based company to adopt tough decisions. While Mr Sinhas next assignment is not clear,people familiar with the matter said financial consultancy and advisory are options that he had been toying with. Prior to Suzlon,Mr Sinha,43,was responsible for setting up and heading Aditya Birla Retail,a completely new business venture under the Aditya Birla fold that had till then limited its operations to commodities and manufacturing.He had also been Group CFO for the Aditya Birla Group before handling the retail operations. In early 2008,Suzlon had raised about $500 million (then about Rs 2,175 crore) through foreign currency convertible bonds and qualified institutional placements to buy stakes in Repower that would give it a global presence in wind turbine technology. But the recession impacted Suzlons profitability and ability to meet payment schedules.Mr Sinha,along with the companys lenders and advisors JP Morgan and Macquarie,pushed to release Suzlon from the financial covenants on the convertible bonds,cut debt and provided the bondholders with a reasonable exit from their investment. Prior to joining the Aditya Birla Group,Mr Sinha had about ten years of experience in international finance including a stint with Citicorp Securities in New York and London,and with ING Barings in New York.