Among the perennial top five lender/servicers, CitiMortgage posted combined big gains in loan production volume with aggressive servicing acquisitions to build up its mortgage business during the first quarter, according to a new analysis by Inside Mortgage Profitability. CitiMortgage turned in a healthy quarter by originating $6.81 billion more than 1Q05 and added $49.5 billion in servicing from 4Q05. … [One data table included]