Wells Fargo remained the top mortgage servicer in the industry at the end of 2012, but the company posted a rare decline in its portfolio during the fourth quarter and is reportedly considering selling some of its massive $1.873 trillion portfolio. A new Inside Mortgage Finance ranking and analysis of the servicing market underscores the gains made in market share by a handful of nonbanks and some regional banks, while some of the top servicers continue to pare their businesses. The servicing industry faces a significant challenge in that increased regulatory requirements are raising operational costs at a time when the overall market continues to decline. On the upside, much of the damage from the housing recession has already occurred...[Includes one data chart]