One of the larger servicing shops you may not have heard of -- yet -- is on the upswing this week, after Fitch Ratings last week boosted the ratings of American Home Mortgage Servicing, Inc. The servicer, once tied to now defunct Alt-A lender American Home Mortgage Corp., was snapped up billionaire investor Wilbur Ross. Fitch said it had upgraded AMHSI's residential primary servicer ratings for prime, Alt-A, and HELOC products to 'RPS3+' from 'RPS3-,' representing a two-notch upgrade for the Irving, Tex.-based servicing shop. Fitch also upgraded American Home's special servicer rating to 'RSS3+' from 'RSS3,' according to a statement. The firm rates servicers on a 5 point scale, with 1 representing the best possible score. The news comes as a positive for American Home, which has reinvented itself in the wake of the former lending arm's bankruptcy and undergone strong growth with the acquisition of the entire Option One Mortgage Servicing platform earlier this year. Fitch said that it believed American Home had "effectively completed the integration of the staff and systems of the AHMSI and OOMC portfolios onto a single servicing system and platform, hired additional experienced managers to complement its executive management team, and efficiently implemented consistent processes across the organization." As of June 30, AHMSI's portfolio consisted of over 433,000 loans with a UPB of nearly $91 billion, up from nearly 173,000 loans with a UPB of $43.5 billion in March 2008 just prior to the acquisition of the OOMC platform. Using 2007 volumes, the combined AHMSI/Option One platform ranks as the nation's 17th largest servicer, according to data provided by Inside Mortgage Finance, an industry trade publication. It's likely that American Home will be on the acquisitions path in 2009 in an effort to further expand its servicing portfolio, according to various sources that spoke with HousingWire on condition of anonymity. The firm has allegedly put in bids with numerous servicing shops that are looking to sell off some or all of their portfolios. Write to Paul Jackson at