What these do is they insure the bond-- they insure the investor against the municipality failing to pay on the bond.

他们的业务是为市政债券保险,他们确保政府当局,有能力向投资者进行赔付

耶鲁公开课 - 金融市场课程节选

That is, the insurance policy doesn't just insure you against death, it also builds value over the years.

也就是说,保单不仅仅,补偿死亡带来的损失,它们还会逐年增值

耶鲁公开课 - 金融市场课程节选