Credit rating agencies played an instrumental role in the development of the collateralized debt obligation market, as the ratings assigned to various tranches allow institutional investors to participate in an otherwise sub-investment grade market.
信用评级机构在担保债务市场的发展中发挥了重要作用，因为机构投资者可以根据各部分债务的评级参与本来属于次级投资等级市场的交易。