Put options writers need to post cash collateral to cover their obligations or go on equivalent margin (which will be monitored and enforced by their broker) in

Put options writers need to post cash collateral to cover their obligations or go on equivalent margin (which will be monitored and enforced by their broker) in order to sell you a put. If this fails, there's still Options Clearing Corporation managing $120B+ collateral and acting as ultimate guarantor for option contracts.