– U.S. health insurer Anthem Inc. is close to finalizing negotiations to acquire peer Cigna Inc. and could announce a roughly $48 billion deal as early as this week, according to a person familiar with the matter.

The deal would follow Aetna Inc.’s $37 billion agreement earlier this month to acquire Humana Inc., potentially reducing the number of major U.S. insurance companies from five to three and attracting antitrust scrutiny.

Most issues that were preventing Anthem and Cigna from reaching a deal, such as price and the role of Cigna Chief Executive David Cordani, have been resolved, the person said, without offering details. Anthem has slightly improved on its previous cash and stock offer of $184 per share, the person added.

The Wall Street Journal earlier reported that Anthem was nearing an agreement to pay about $187 per share for Cigna. Cigna shares closed Wednesday at $155.10.

The source asked not to be identified because the negotiations between the companies are confidential. Anthem and Cigna did not immediately respond to requests for comment.

Health insurers have been in a race to consolidate, arguing that being larger would help them negotiate better prices with doctors and hospitals as well as cut administrative costs after President Obama’s health care law.

Many health care providers are concerned, however, that further consolidation will decrease competition in the insurance industry.