no buyers for the risky assets u either leave them as is or u write down their value. Remember banks think within silos only their bank their business, they think eveyrone else is dodgy u can expect every other bank is as risk aversive, without central bank support they all basically become timid deer n the headlights- given debts massive role in current economic and capitalists activities its like its own currency u stop it flowing u shut the economy down ( as we are seeing) Herds act irrationally