...The Pittsburgh-based plan is the fourth-largest BCBS plan in the nation. Highmark Inc. is the lead insurance subsidiary of Highmark Health (unrated), which also owns Allegheny Health Network (AHN), a hospital system in Western Pennsylvania. Highmark is one of several large health plan consolidators in the BCBS system. At year-end 2020, Highmark Inc. covered about 4 million medical members in Pennsylvania (PA), Delaware (DE), and West Virginia (WV). In March 2021, Highmark added HealthNow New York Inc., the BCBS health plan in western and northeastern New York, as a controlled affiliate. The transaction added about 700,000 medical members....