yield to maturity是给定债券当期价格和未来的现金流求出来的内部收益率irr。即债券现金流用ytm折现就是债券价格price。coupon rate是债券规定的票面利息，而interest rate是无风险利率如存款利率、libor。只有平价发行的时候ytm,coupon rate,interest rate才相等吧。我是这么理解的，没有frm的书，也帮不了楼主了。

感谢啊！！！！

market interest rate不是无风险利率吧，我理解是市场的spod interest

YTM is the annualised return which takes into account the expected coupons, the face value and the price you paid. If you paid higher than face value, YTM is less than coupon rate.

In practice YTM is a function of risk. As an example, if you are buying a junk bond, you will demand a YTM that is at least as high as the yields for similarly high risk investments. But if you are buying something very safe, you will only get a YTM that is about the same as the risk-free market interest rate.