Officials at Envision Healthcare Holdings and AmSurg are in advanced discussions regarding a potential merger, with a deal to be announced as early as next week, sources tell The Wall Street Journal.  

It's not on the level of the Anthem-Cigna or Aetna-Humana mergers, but it's a big deal nonetheless. The estimated combined value of the two health care providers is $9 billion.  

More importantly, the merger is yet another sign of an increasingly consolidated health care industry, every segment of which has seen an acceleration of mergers and acquisitions in recent years.  

Nashville, Tenn.-based AmSurg is one of the top providers of ambulatory surgery centers, operating 250 facilities across the country where patients can go under the knife without having to stay overnight. In 2014 it also acquired Sheridan Healthcare, a major physician services company, for $2.3 billion, to provide outsourced medical services to hospitals.  

Greenwood Village, Colo-based Envision similarly provides outsourced physician services and is a major player in providing ambulance and private fire protection services, particularly to small or rural communities across the country.  

This is the second time in the past year that AmSurg has sought a partnership with a competitor. In 2015, it offered TeamHealth more than $5 billion, a proposal the latter company rejected, saying it was too low.