Most servicers of Fannie Mae and Freddie Mac single-family mortgage-backed securities saw growth in their servicing portfolios during the third quarter, but a handful of top banks continued to buck the trend.A new Inside The GSEs analysis of MBS disclosures shows $4.629 trillion of Fannie/Freddie servicing outstanding at the end of September. That was up 1.8 percent from the previous quarter, with Fannie (up 2.1 percent) gaining market share on Freddie (up 1.3 percent). Ginnie Mae servicing remained a faster-growing market, with $1.749 trillion outstanding, up 2.2 percent from the end of June. Large banks continued to show tepid interest in the GSE servicing market.