The contract with AIG is a derivatives contract, which goes through the clearinghouse; but the contract with Citibank is another kind of contract, maybe just a regular loan, and does not go through the clearinghouse. BofA also has a contract with, say, Bear Stearns through the clearinghouse for $100 million, with Bear Stearns on the losing end.
我们来看看原因。假设某疲软金融机构（比如美国银行）握有两张独立合约，一张的对手是AIG，另一张是花旗银行。美国银行欠这两者每人1亿美元。与AIG的合约是衍生品合约，通过清算所交易；但与花旗银行的合约类型有所不同，比如属于常规贷款，因此并不经过清算所进行。美国银行手上还有第三张合约（假设对手是贝尔斯登），这张合约通过清算所进行，价值1亿美元，但亏损方是贝尔斯登。