It refers to the bondissuer reimburse the principles and interest of the bond before it matures.
指债券发行人在债券到期日之前便将本息还清，以达到债券的提前赎回。
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Just as house insurance will cost more for those living next to a fireworks factory, a CDS becomes more expensive when the finances of the bondissuer deteriorate (see chart).
Under a CDS, one party seeks to protect itself against the default of a bondissuer by paying an annual sum—the equivalent of an insurance premium—to someone else who wants to take on the risk.