Financial engineers worked their mysterious magic with these securities , turning the junkiest mortgages into high - grade , sometimes aaa - rated , securities 金融工程師變魔術般的將最垃圾的抵押貸款制作成高信用等級(有時甚至達到aaa級)的證券。
These include supposedly impregnable “ super - senior ” and aaa - rated tranches of cdos that a short time ago were prized by the world ' s banks , insurance companies and mutual funds 不久前某些抵押債權憑證還被各大銀行、保險公司和共同基金譽為“頂級” ,給予aaa評級,認為它們永遠不會垮掉。