Standard & Poor's Ratings Services said earlier this week that it had deferred its annual review of its residential servicer rankings on American Home Mortgage Servicing Inc. (AHMSI), to allow the company time to complete its most recent acquisition. On Feb. 4, AHMSI announced that it had acquired the servicing rights to some 185,000 residential mortgages for $1.5 billion from Citigroup, Inc. (C), a $28 billion servicing portfolio. Standard & Poor's currently maintains 'average' rankings on the company for residential prime and residential subordinate-lien loan servicing. The company also now has a 'strong' ranking for residential subprime loan servicing and an 'average' ranking for residential special loan servicing, both of which were previously assigned to Option One Mortgage before AHMSI purchased the company last June. "Standard & Poor's acknowledges the growth and significant changes that come with the company's purchase of Option One, as well as the company's recently announced acquisition of a $28 billion servicing portfolio from Citi Residential Lending," the agency said in a statement. "As such, we will defer our annual review of AHMSI's servicing operations to allow senior management adequate time to complete the most recent integration." American Home has been on a roll as of late, and has been adding staff at a fast clip ahead of and in the wake of its most recent acquisition. AHMSI expanded its operational audit function by adding experienced management and staff in mid-2008 to develop a separate internal audit function, S&P noted. The agency said it plans update its residential servicer rankings on AHMSI within the next 90-120 days. Write to Paul Jackson at paul.jackson@housingwire.com.