Many mutual and building societies (like German Schwäbisch Hall) have a "closed system": they don't borrow/lend the money from/to central bank and open marked,

Many mutual and building societies (like German Schwäbisch Hall) have a "closed system": they don't borrow/lend the money from/to central bank and open marked, but only from/to their clients. Those are isolated islands, mostly independent from financial system are are immune to crisis happening outside of their closed system...