http://www.google.com/search?q=HMO+Co-Op+Cooperatives&hl=en&lr=&safe=off
One of my ex'es worked for Group Co-Op Hospital in Seattle for about a decade as an admin. asst. http://www.ghc.org/web/ They were one of the first HMO's, founded in the late 40's. Last time I visited we went to a African-American cultural festival, ran into a fellow staffer for Group Co-Op, she was a former Black Panther Party member that was their (GHC) coordinator for clinics in the underserved communities.
GHC, was bought out by Kaiser, though a few years ago. Washington State btw, because of the Washington Commonwealth Federation of the 30's has alot of cooperativism. The Federation elected many lefties (including Hugh deLacy, a CPUSA'er and later Progressive Party candidate, to Congress in the late 30's) to political office. Wonder how many EPIC in California did? One was Sam Yorty, later a stone cold reactionary. Michael Pugliese