Moody's said a combination of CVS Health Corp. and Aetna Inc. would have negative implications for other health care companies by virtue of its scale and strength.
CVS offered to buy health insurer Aetna in a deal valued at about $69 billion, making it the largest managed-care deal in more than two years.
The proposed deal would pave the way for a network of all-in-one medical treatment centers, allowing patients to seek common medical treatments, fill prescriptions and manage their health insurance plans.
Moody's said CVS's pharmacy benefit manager, on combining with Aetna, would offer a more integrated approach to managing total healthcare costs which would disadvantage other pharmacy benefit managers including Express Scripts Holding Co.
"While the effects to the industry would not be immediate, the merger, if completed, would create an enormous, vertically-integrated firm, competing in multiple aspects of health care delivery," said Moody's senior vice president Michael Levesque.
In the long term, the combination of would result in pricing and utilization pressure for branded drug companies, the rating agency said.
Moody's said the merger and acquisitions will continue to involve non-traditional pairings of various entities, adding that the combination would eventually pressure the utilization and pricing of hospital-based drugs that fall outside the traditional realm of pharmacy benefit managers.
