International private equity company 3i Group saw an 'encouraging increase in activity' in its markets in the final quarter of 2010.The group invested £183m in the three month period at the end of the year, bringing the total investment for the first nine months of the group's financial year up to £510m; that is more than double the £249m invested in the corresponding period of 2009.In addition, £158m was invested in the quarter on behalf of co-investment funds managed by 3i, well up on the previous year's £34m.Realisations in the quarter totalled £105m, raising the nine month total to £398m, down from £777m the year before. Total proceeds do not include the expected sales proceeds from the sales of MWM and Hyva, which together will be around £350m.The group had cash, cash deposits and undrawn committed facilities of £1.91bn as at 31 December 2010, up from £2.13bn at the end of September 2010. Net cash investment in the three month period was £69m and net debt increased by £115m to £467m.