A.M. Best Co. has affirmed the financial strength rating of A- (Excellent) and issuer credit ratings of “a-” of Medco Containment Life Insurance Company (MCLIC) (headquartered in Franklin Lakes, NJ) and Medco Containment Insurance Company of New York (MCICNY) (Clifton Park, NY). The outlook for all ratings is stable. The ratings are based on MCLIC and MCICNY’s continued favorable operating results, strong capitalization at both entities and the strategic importance of their ultimate parent company, Express Scripts Holding Company (Express Scripts) [NASDAQ: ESRX]. During 2012, these companies were acquired by Express Scripts, and the newly merged organization is the largest pharmacy benefit manager in the United States. Each respective company’s underwriting results have been trending favorably over the medium term driven by margin improvement. Capital levels at the companies are more than adequate for their current level of business. Near-term capital growth levels are mainly the result of strong net earnings and lack of dividends paid. A.M. Best expects capital support will be provided by Express Scripts, when necessary. MCLIC and MCICNY offer very limited product portfolios, which primarily consist of Medicare Part D business offered to Express Scripts’ clients and individuals. All long-term revenues are expected to be derived from Medicare Part D products. This narrow focus on Medicare poses a market concentration risk. A.M. Best expects that MCLIC and MCICNY will focus their business in support of Express Scripts’ clients. Factors that may positively affect the ratings include a change in product diversity and sustained long-term earnings. Key rating drivers that could lead to negative rating actions include a trend of losses, capital deteriorating beyond A.M. Best's expectations or the Medco companies becoming less strategically important to Express Scripts. The methodology used in determining these ratings is Best’s Credit Rating Methodology, which provides a comprehensive explanation of A.M. Best’s rating process and contains the different rating criteria employed in the rating process. Best’s Credit Rating Methodology can be found at www.ambest.com/ratings/methodology. A.M. Best Company is the world's oldest and most authoritative insurance rating and information source. For more information, visit www.ambest.com. Copyright © 2013 by A.M. Best Company, Inc. ALL RIGHTS RESERVED.