Employers display a wide range of opinions about the recent mergers of major health insurance companies.

Anthem, the country's second largest health insurer, announced plans Friday to buy Cigna, the fifth largest. That follows news earlier this month that the third and fourth largest insurers, Aetna and Humana, would similarly merge.

"Large employers will have concerns about the merger between Anthem and Cigna because employers will be left with only three major insurers who can support large multi-state employers on a nationwide basis," Brian Marcotte, president of the National Business Group on Health (NBGH), said in a statement. "Many large employers offer more than one national plan to provide employees with choice, cover provider network gaps and to have insurers compete on performance, strategy, cost management and innovation."