A.M. Best has affirmed a pair of ratings for the former AIG Personal Lines Group, which includes 21st Century Insurance, in light of its acquisition by Farmers Insurance Group.

The ratings service affirmed the financial strength ratings of “A” (Excellent) and issuer credit ratings of “a” for the 17 companies under the former AIG personal lines division, which include American International Insurance Cos. of Delaware and New Jersey and AIG Auto Insurance Co. of New Jersey.

In addition, the ICR and debt rating of “bbb” have been affirmed on the $100 million of senior unsecured notes of 21st Century Insurance Group an intermediate holding company, according to A.M. Best.

All ratings outlooks have been revised to “stable” from “negative.”

Farmers completed its acquisition of AIG’s Personal Lines Group July 1 for a purchase price of $1.9 billion. Farmers is a Los Angeles, Calif.-based subsidiary of Zurich Financial Services Group.

The acquisition strengthens Farmers’ market share, A.M. Best said, broadens its geographic and product diversity and accelerates entry into the direct to consumer market. While there are potential integration risks due to the size of the transaction, the ratings service anticipates the overall operational impact “will be manageable,” given Farmers’ diverse product offerings and previously successful acquisition performance.

A.M. Best has withdrawn the ratings of 21st Century Insurance Cos. and AIG Personal Lines Group and assigned the financial strength ratings a category NR-5 (Not Formally Followed) and the issuer credit ratings an “nr.”