The not-for-profit giants have signed a nonbinding agreement to evaluate “an alignment” between the systems.

A  merger would create the nation’s largest not-for-profit hospital company with combined revenue of $27.6 billion ahead of the $20.5 billion of  Catholic-sponsored Ascension. A CHI-Dignity union would make it the second-largest not-for-profit hospital system, with Kaiser Permanente continuing as the largest.

The companies didn’t disclose terms of the agreement, but did  cite   their new partnership, called the Precision Medicine Alliance, which the two systems called America’s largest community-based precision- medicine program.

The  companies’ statement  cited ways in which they say the systems complement each other. For example, Englewood, Col.-based CHI has 103 hospitals in 18 states and focuses on clinical and home-health services in addition to research while Dignity “is well known for its work with innovative, diversified care-delivery partnerships.”

San Francisco-based Dignity Health, with 39 hospitals, operates in 22 states with 9,000 physicians, 62,000 employees and 400 care centers.