Cigna Corporation (NYSE:CI) has confirmed it received a highly conditional, non-binding proposal from Anthem, Inc. (NYSE: ANTM) on June 20, 2015.

Cigna’s Board of Directors has carefully reviewed this proposal consistent with the company’s continued focus on maximizing shareholder value and creating differentiated value for its customers, clients and other stakeholders in a dynamic, rapidly-evolving healthcare environment.

Based on a number of factors in the proposal and unaddressed concerns regarding the ability to achieve the benefits of a potential combination, the Cigna Board has unanimously determined the proposal is inadequate and not in the best interests of Cigna’s shareholders. Cigna’s letter to Anthem’s Board of Directors that details these factors and concerns is included in this press release below.

Cigna’s mission is to improve the health, well-being and sense of security of the people we serve. Effective execution of our focused strategy has driven a consistent track record of strong financial performance and successful shareholder value creation. Since implementing its “Go Deep, Go Global, Go Individual” strategy over five years ago, Cigna has delivered compound annual growth of 14% for revenues and 13% for adjusted income from operations.

As a result, Cigna’s share price rose almost 200% in the five years beginning December 31, 2009. Anthem shares, however, significantly lagged the performance of both Cigna and the Managed Care peer group (as defined in Anthem’s most recent proxy statement) in the same period.

Morgan Stanley is acting as Cigna’s financial advisor, and Cravath, Swaine & Moore is acting as legal advisor to Cigna.