The general pickup in housing activity in early 2012 is welcome news for a mortgage industry both gearing up to unload significant numbers of foreclosed properties and looking to increase home purchase financing this year. But the fact that investors are driving much of the recent surge in home sales is not necessarily good news for mortgage interests. According to the latest Campbell/Inside Mortgage Finance HousingPulse Tracking Survey, the investor share of home purchases hit a record-high of 24.2 percent in February based on a three-month moving average. That was up from a 20.9 percent...