Private equity group 3i has bought another chunk of bonds for cancellation.The company has bought £28.55m of its 3.625% convertible bonds due 2011 in the market for cancellation.The purchase follows a £27.65m purchase of bonds for cancellation announced on 21 May.Following cancellation there will remain £228.6m of the original £430m bond issue.In March 2010, the group issued a €350 million bond at 5.625% with a seven year maturity, in a move that group said further extended the maturity profile of its debt at attractive terms.The group's net debt at the end of March had been reduced to £258m from £1,912m at the end of March 2009.