Private equity house 3i ramped up investment and swung into profit during the first half.Profit before tax came in at £54m for the six months ended 30 September compared with a £57 loss in 2009, helped by a much smaller exchange rate hit. The net portfolio return rose by £4m to £236m.3i realised £293m during the period, down from £507m a year ago, and invested £327m, up from £190m last time.Assets under management slipped to £9.3bn from £9.7bn in 2009 as a £200m increase in external funds was easily cancelled by a £500m drop at 3i.In his first set of results as chairman, Sir Adrian Montague said market conditions and the outlook for the business have improved compared to this time last year, though he is cautious. "A considerable degree of macroeconomic uncertainty remains in many of the regions in which we operate as governments continue to wrestle with the twin challenges of reducing deficits and stimulating growth. It will therefore be important to continue to take a measured approach as we take advantage of opportunities to invest and grow."The interim dividend goes up from 1p to 1.2p a share.