The　objective　of　this　paper　is　to　identify　whether　the　interorganization　of　healthcare　providers　in　China　had　the　global　property　of　an　oligopoly　market　tendencies　by　analyzing　the　rich-club　phenomenon　of　patient　flow.　This　paper　examines　the　properties　of　patient　transfer　networks　in　an　entire　province　of　China　using　social　network　analysis.　Hypertension　is　one　of　the　most　prevalent　chronic　conditions　in　China,　thus　the　study　examined　the　transfer　network　of　patients　with　hypertension.　The　rich-club　coefficient,　the　assortativity　coefficient,　and　community　detection　were　used　to　quantitatively　illustrate　the　rich-club　tendency　of　the　social　network.　The　results　reveal　significant　rich-club　characteristics　and　regional　clustering　patterns　in　this　transfer　network.　First,　the　global　rich-club　coefficients　calculated　based　on　both　degree　and　weighted　degree　are　larger　than　1,　suggesting　a　relatively　noticeable　rich-club　effect.　Second,　269　nodes　(69.33%)　attach　only　to　rich　nodes,　suggesting　that　most　nodes　within　the　hypertensive-patient　transfer　network　are　highly　influenced　by　rich-club　members.　Third,　community　detection　found　a　significant　pattern　of　regional　clustering　in　the　transfer　network.　Our　findings　are　the　first　to　demonstrate　that　the　hospital　system　operated　as　an　oligopoly　market,　in　which　the　＂elite＂　providers　formed　an　＂inner　circle＂,　and　other　providers　were　only　loosely　interconnected.　It　might　be　valuable　to　patients　to　transfer　this　oligarchical　system　into　a　more　pluralistic　network.　(C)　2020　Published　by　Elsevier　B.V.