Highmark has announced the finalization of a deal to affiliate with a Buffalo-based health care system.

New York will make the fourth state with Highmark health care plans, now that the agreement with HealthNow is complete.

The $2.9 billion nonprofit company has Blue Cross Blue Shield plans in northeastern and western New York.

In the agreement, Highmark must keep local employees and invest at least $2 million annually in HealthNow communities to decrease health disparities.

HealthNow will become Highmark Western and Northeastern New York, and its two health plans will be rebranded as Highmark Blue Cross Blue Shield of Western New York and Highmark Blue Shield of Northeastern New York.

HealthNow’s CEO, Dave Anderson, will lead the division until he retires at the end of the year.

While Anderson will continue on the board of directors, Dr. Michael Edbauer of HealthNow will become president of the new affiliate.

“As the integration of our companies begins, I will plan my departure knowing that we’ve positioned this organization for tremendous success in the years ahead,” Anderson said in a news release.

Deborah Rice-Johnson, Highmark president, said she looks forward to the collaboration.

“With this affiliation, we begin our path forward to enhance customer and clinician engagement, create better health outcomes, control costs and improve affordability for members in Western and Northeastern New York,” she said.