Anthem Inc. refuses to back down from a potential merger with Cigna Corp., despite its rival's rejection on Sunday of Anthem's latest offer.

In a conference call Monday, Anthem executives reiterated the Indianapolis-based health insurer's determination to merge with Bloomfield, Connecticut-based Cigna, a combination Anthem CEO Joseph Swedish said would help the insurers drive greater efficiency and affordability for customers, and position them strongly in growth markets.

In its fourth offer to Cigna made Saturday, Anthem, part of the Blue Cross and Blue Shield Association, valued its smaller rival at $184 per share, or roughly $47 billion. Anthem also proposed the combined organization's board of governors would comprise 10 board directors from Anthem and three from Cigna.

Mr. Swedish said the combined organization would generate $115 billion in annual revenues and serve more than 53 million people combined.

“We have offered a clear, comprehensive and compelling offer,” Mr. Swedish said during the conference call to Anthem's investors and media when asked if any further concessions will be made.

Cigna, however, in a letter Sunday to Anthem's board of directors, rejected the offer as “inadequate and not in the best interests of Cigna's shareholders.”

The letter cited a number of issues, including a lack of a growth strategy, complications relating to obtaining licensure from the Blue Cross and Blue Shield Association and antitrust laws, and the data breach Anthem experienced in February.

Cigna also expressed concern with the governance of the combined organization, calling Anthem's proposal that Mr. Swedish serve as chairman, CEO, president and head of integration “disconcerting and risky.”

During the conference call, Mr. Swedish said he is confident Anthem will obtain regulatory approvals from the Blue Cross and Blue Shield Association, and that no antitrust or insurance regulatory issues will prevent the deal.

Mr. Swedish also said a 10 to three split regarding board compensation is aligned with precedent transactions.

Though Mr. Swedish would not elaborate on the next steps in the negotiation process, he said, “We're certainly desirous that this process can move into a successful outcome.”