Four of the top five mortgage servicers continued to gradually pare down their portfolios during the second quarter of 2011, while Wells Fargo inched further toward the top of the industry, according to a new ranking and analysis by Inside Mortgage Finance. Absent any blockbuster mergers or servicing acquisitions over the past few years, the major trend in the servicing business has been the winding down of distressed subprime and Alt A portfolios. Bank of America, still the largest servicer in the industry, has seen its portfolio shrink steadily since ... [includes one data chart]