OLDWICK, N.J.--(BUSINESS WIRE)--A.M. Best’s latest special report on the long-term impairment rates of A.M. Best-rated U.S.-domiciled insurance companies notes that four property/casualty insurers were added to the impaired companies list in 2014. The Best’s Special Report, titled, “Best’s Impairment Rate and Rating Transition Study — 1977 to 2014,” marks the 12th study conducted. The analysis covers 37 one-year periods from Dec. 31, 1977 to Dec. 31, 2014 and includes only companies that had a